Andersen - The Hippocampus Book
Book Page   Topic    
Andersen; Hippocampus Book 3 The Hippocampal Formation
Andersen; Hippocampus Book 9 Historical Perspective: Proposed Functions, Biological Characteristics and Neurobiological Models of Hippocampus 6
Andersen; Hippocampus Book 37 Hippocampal Neuroanatomy 28
Andersen; Hippocampus Book 38 Hippocampal Formation (diagram) 1
Andersen; Hippocampus Book 38 A common organizational feature of connections between regions of the neocortex is that they are largely reciprocal. 0
Andersen; Hippocampus Book 38 The entorhinal cortex can be considered the first step in the intrinsic hippocampal circuit. 0
Andersen; Hippocampus Book 38 Cells in the superficial layers of the entorhinal cortex give rise to axons that project to the dentate gyrus. 0
Andersen; Hippocampus Book 38 The projections from the entorhinal cortex to the dentate gyrus form part of the major hippocampal input pathway called the perforant path. 0
Andersen; Hippocampus Book 38 The dentate gyrus    does not project back    to the entorhinal cortex. 0
Andersen; Hippocampus Book 38 The pathway between entorhinal cortex and dentate gyrus is unidirectional. 0
Andersen; Hippocampus Book 38 The principal cells of the dentate gyrus, the granule cells, give rise to axons called mossy fibers that connect with pyramidal cells of the CA3 field of the hippocampus. 0
Andersen; Hippocampus Book 38 The CA3 cells do not project back to the granule cells of the dentate gyrus. 0
Andersen; Hippocampus Book 38 Pyramidal cells of CA3 are the source of the major input to the CA1 hippocampal field (the Schaffer collateral axons). 0
Andersen; Hippocampus Book 39 The CA1 field of the hippocampus    projects unidirectionally    to the subiculum. 1
Andersen; Hippocampus Book 39 From CA1 and subiculum,    the pattern of intrinsic connections    begins to become somewhat more elaborate. 0
Andersen; Hippocampus Book 39 CA1 projects not only to the subiculum but also to the entorhinal cortex. 0
Andersen; Hippocampus Book 39 Whereas the subiculum does not project to the presubiculum and a parasubiculum, its more prominent cortical projection is directed to the entorhinal cortex. 0
Andersen; Hippocampus Book 39 Both CA1 and the subiculum close the hippocampal processing loop that begins in the superficial layers of the entorhinal cortex and ends in its deep layers. 0
Andersen; Hippocampus Book 39 The hippocampal formation is organized in a fashion that is distinctly different from most other cortical areas. 0
Andersen; Hippocampus Book 39 Although the volume of the hippocampus is about 10 times larger in monkeys than in rats and 100 times larger in humans than in rats, the basic hippocampal architecture is common to all three species. 0
Andersen; Hippocampus Book 39 Although the hippocampal formation is often portrayed as a phylogenetically primitive brain region, it has substantial species differences. 0
Andersen; Hippocampus Book 39 Prominent role of the rat in current functional analyses of hippocampal formation. 0
Andersen; Hippocampus Book 39 Far less work has been carried out on the hippocampus of the mouse, the clear choice for molecular biology studies. 0
Andersen; Hippocampus Book 39 The term hippocampus (derived from the Greek word for seahorse) was first coined during the 16th century by the anatomist Arantius (1587). 0
Andersen; Hippocampus Book 41 Subdivisions of the hippocampus are referred to using abbreviations of cornu ammonis (CA3, CA2, CA1). 2
Andersen; Hippocampus Book 41 A classic article published in 1947 concluded that the hippocampus could not be functioning solely as an olfactory structure. 0
Andersen; Hippocampus Book 41 During the 1930s, the neurologist James Papez considered the hippocampus to be a central component of a system for emotional expression. 0
Andersen; Hippocampus Book 41 In many textbooks the hippocampus is still claimed to be the central component of the so-called Papez circuit. 0
Andersen; Hippocampus Book 41 The role of orchestrator of emotional expression is now closely linked with another prominent medial temporal lobe structure, the amygdaloid complex. 0
Andersen; Hippocampus Book 41 The hippocampus is associated with the term "limbic system." 0
Andersen; Hippocampus Book 41 The origin of the term "limbic system" stems from the description by neurologist Broca (1878). 0
Andersen; Hippocampus Book 41 The number of structures including under the rubric "limbic system" has escalated dramatically    since the 1950s. 0
Andersen; Hippocampus Book 42 Several synonymous terms are still commonly employed for structures of the hippocampus. 1
Andersen; Hippocampus Book 42 The term hippocampus is reserved for the region of the hippocampal formation that comprises the fields CA3, CA2, CA1. 0
Andersen; Hippocampus Book 42 The term hippocampus formation is applied to a group of distinct adjoining regions including the dentate gyrus,    hippocampus,    subiculum,    presubiculum,    parasubiculum,    and entorhinal cortex. 0
Andersen; Hippocampus Book 42 The six structures of the hippocampus formation are linked, one to the next, by a unique and largely unidirectional (functional) neuronal pathways. 0
Andersen; Hippocampus Book 42 Early literature on the hippocampus formation (1971) emphasized the first three links of the hippocampal circuitry by applying the term "trisynaptic circuit" to the ensemble of pathways.  0
Andersen; Hippocampus Book 42 (EC -- DG (synapse 1) -- CA3 (synapse 2) -- CA1 (synapse 3) 0
Andersen; Hippocampus Book 42 Projections from CA1 to the subiculum and entorhinal cortex,    and a major projection from the entorhinal cortex to the neocortex,    the tri-synaptic circuit is now considered to be only a portion of the functional circuitry of the hippocampal formation. 0
Andersen; Hippocampus Book 42 The subiculum is the main source of subcortical projections. 0
Andersen; Hippocampus Book 42 The entorhinal cortex is a main source of projections to the neocortex. 0
Andersen; Hippocampus Book 42 The term hippocampal formation is widely, though not universally, accepted. 0
Andersen; Hippocampus Book 42 Allocortical -- a term applied to cortical regions having fewer than six layers. 0
Andersen; Hippocampus Book 42 Three-layered cortical regions    typically have a single neuronal cell layer    with fiber-rich plexiform layers    above and below the cell layer. 0
Andersen; Hippocampus Book 42 Clarification of the nomenclature    is typically the first sign of maturity    for scientific enterprise. 0
Andersen; Hippocampus Book 43 The entorhinal cortex is the only hippocampal region that unambiguously demonstrates a multilaminate appearance. 1
Andersen; Hippocampus Book 43 Given the complex shape of the hippocampal formation,    no reference system is wholly adequate,    and any description inevitably involves arbitrary decisions    about where to start or finish,    which direction is up or down, etc. 0
Andersen; Hippocampus Book 43 The dentate gyrus is considered to be the proximal pole of the hippocampal formation,    and the entorhinal cortex is the distal pole. 0
Andersen; Hippocampus Book 43 In six-layered structures,    layer I is close to the pial surface,    and layer IV is located close to the subcortical white matter. 0
Andersen; Hippocampus Book 43 As an electrophysiologist    advances an electrode    from the dorsal surface of the brain    toward the hippocampus. 0
Andersen; Hippocampus Book 47 A major fiber pathway associated with the hippocampal formation is the angular bundle, a fiber bundle interposed between the entorhinal cortex and the presubiculum and parasubiculum. 4
Andersen; Hippocampus Book 47 The perforant path comprises the afferent entorhinal projections    that traverse, or perforate, the subiculum    on their way to the dentate gyrus in the hippocampus. 0
Andersen; Hippocampus Book 47 The fornix    is a continuation of a bundle of hippocampal output fibers    to subcortical target structures. 0
Andersen; Hippocampus Book 48 A third major fiber system associated with the hippocampal formation is a commissural system. 1
Andersen; Hippocampus Book 48 Commissural fibers are directed to the contralateral hippocampal formation. 0
Andersen; Hippocampus Book 49 The classic gross anatomical image of the human hippocampal formation is a prominent bulge in the floor of the temporal horn of the lateral ventricle. 1
Andersen; Hippocampus Book 55 The dentate gyrus is comprised of three layers. 6
Andersen; Hippocampus Book 55 The principal cell type of the dentate gyrus is a granule cell. 0
Andersen; Hippocampus Book 55 Each granule cell is closely opposed to the other granule cells,    and in most cases there is no glial sheath    intervening between the cells. 0
Andersen; Hippocampus Book 55 The granule cell has a characteristic cone shaped tree of spiny dendrites with all the branches directed toward    the superficial portion of the molecular layer. 0
Andersen; Hippocampus Book 55 Estimates of the number of spines on granule cells ranged from 5600 to 3600. 0
Andersen; Hippocampus Book 55 Although cell proliferation and neurogenesis in the dentate gyrus    persist into adulthood,    the total number of granule cells    does not vary in adult animals. 0
Andersen; Hippocampus Book 55 Only infant and juvenile mice exposed to an "enriched" environments demonstrate a larger dentate gyrus and a greater number of granule cells that persist into adulthood. 0
Andersen; Hippocampus Book 55 Dendritic arborization of the principal cells in the rat dentate gyrus (diagram) 0
Andersen; Hippocampus Book 56 The granule cell is the only principal cell of the dentate gyrus. 1
Andersen; Hippocampus Book 56 The most intensively studied interneuron is the pyramidal basket cell. 0
Andersen; Hippocampus Book 56 Basket cell axons form plexuses    that surround and form synapses    with the cell bodies of granule cells. 0
Andersen; Hippocampus Book 56 Hippocampal interneurons form a heterogeneous population. 0
Andersen; Hippocampus Book 56 Many of the interneuronal cell types can be distinguished by the distribution of their axonal plexus. 0
Andersen; Hippocampus Book 56 Some interneurons have axons that terminate on cell bodies, whereas others have axons that terminate exclusively on the initial segment of other axons. 0
Andersen; Hippocampus Book 57 Some interneurons have high rates of spontaneous activity    and fire in relation to the theta rhythm. 1
Andersen; Hippocampus Book 57 Morphological classification of interneurons of the rat dentate gyrus (diagram) 0
Andersen; Hippocampus Book 58 The polymorphic layer harbors a variety of neuron types, but little is known about many of them. 1
Andersen; Hippocampus Book 59 Entorhinal Cortex Projection to the Dentate Gyrus 1
Andersen; Hippocampus Book 59 Perforant fibers terminate exclusively in the molecular layer. 0
Andersen; Hippocampus Book 60 The dentate gyrus receives relatively few inputs from subcortical structures. 1
Andersen; Hippocampus Book 61 The major hypothalamic projections to the dentate gyrus arises from the supramammillary area. 1
Andersen; Hippocampus Book 61 The dentate gyrus receives a particularly prominent noradrenergic input    from the pontine nucleus locus coeruleus. 0
Andersen; Hippocampus Book 61 The dentate gyrus receives a minor, diffusely distributed dopaminergic projection    that arises mainly from cells located in the ventral tegmental area. 0
Andersen; Hippocampus Book 61 The serotonergic projection that originates from medial and dorsal divisions of the raphe nuclei    also terminates most heavily in the polymorphic layer. 0
Andersen; Hippocampus Book 61 A number of GABAergic interneurons    appear to be preferentially innervated    by the serotonergic fibers. 0
Andersen; Hippocampus Book 62 A variety of basket cells are located just below the granular cell layer and appeared to contribute to an extremely dense trauma plexus and is confined to the granular cell layer. 1
Andersen; Hippocampus Book 62 The granules cells give rise to distinctive unmyelinated axons called mossy fibers. 0
Andersen; Hippocampus Book 62 The mossy fibers have unusually large blue times that form en passant synapses with CA3 pyramidal cells. 0
Andersen; Hippocampus Book 63 Although the neuroanatomy of the hippocampal formation has been analyzed for many years, new component of its intrinsic circuitry continued to be discovered. 1
Andersen; Hippocampus Book 64 The dentate gyrus does not project any brain region other than the CA3 field of the hippocampus. 1
Andersen; Hippocampus Book 64 All dentate granule cells project to CA3. 0
Andersen; Hippocampus Book 64 Mossy fibers give rise to unique, complex en passant presynaptic terminals called mossy fiber expansions. 0
Andersen; Hippocampus Book 64 Mossy fiber presynaptic terminals can be as large as 8 µ in diameter but more typically range from 3 to 5 µ. 0
Andersen; Hippocampus Book 64 The mossy fiber expansions form highly irregular, complex, interdigitated attachments with the intricately branched spines called excrescences that are located on the proximal dendrites of the CA3 pyramidal cells. 0
Andersen; Hippocampus Book 64 The thorny excrescences are so distinctive that they clearly mark the location of mossy fiber synaptic termination. 0
Andersen; Hippocampus Book 64 Another distinctive feature of the mossy fiber expansion is the number of active synaptic zones. 0
Andersen; Hippocampus Book 64 A single mossy fiber expansion can make as many as 37 synaptic contacts with a single CA3 pyramidal cell dendrite. 0
Andersen; Hippocampus Book 64 Although a mossy fiber expansion may be in synaptic contact with more than one complex spine originating from the same pack dendrite, it does not typically contact spines on two different dendrites. 0
Andersen; Hippocampus Book 64 One mossy fiber expansion does not typically contact to pyramidal cells. 0
Andersen; Hippocampus Book 64 The large mossy fiber expansions occur approximately every 135 µ along the apparent axon and each mossy fiber axon forms about 15 of these complex boutons. 0
Andersen; Hippocampus Book 66 Each granule cell communicates with only 15 CA3 pyramidal cells. These 15 pyramidal cells are distributed throughout the full-length of CA3. 2
Andersen; Hippocampus Book 66 Each pyramidal cell is expected to receive input from about 70 to granule cells. 0
Andersen; Hippocampus Book 66 There is substantial evidence indicating that granule cells use glutamate as their primary transmitter. 0
Andersen; Hippocampus Book 67 Mossy fibers are also immunoreactive reactive for several other neuroactive substances. 1
Andersen; Hippocampus Book 67 The laminar organization is generally similar for all fields of the hippocampus. 0
Andersen; Hippocampus Book 67 The pyramidal cell layer is tightly packed in CA1 and is more loosely packed in CA2 and CA3. 0
Andersen; Hippocampus Book 68 In contrast to the substantial heterogeneity of dendritic organization characteristic of CA3 pyramidal cells,    the CA1 pyramidal cells show remarkable homogeneity of their dendritic trees. 1
Andersen; Hippocampus Book 68 The total dendritic length of CA1 pyramidal cells averages approximately 13.5 mm. 0
Andersen; Hippocampus Book 68 Some pyramidal cells have one apical dendrite and others have two. 0
Andersen; Hippocampus Book 68 Pyramidal neurons are by far the most numerous neurons in the hippocampus. 0
Andersen; Hippocampus Book 68 As in the dentate gyrus, there is a fairly heterogeneous group of interneurons in the hippocampus that are scattered through all layers. 0
Andersen; Hippocampus Book 69 Summary of the organization of hippocampal pyramidal cells produced as computer-generated line drawings of neurons from CA3, CA2, and CA1. (diagram) 1
Andersen; Hippocampus Book 69 Morphological classification of the interneurons in the hippocampus (diagram) 0
Andersen; Hippocampus Book 70 A second type of hippocampal interneuron is the chandelier, or axo-axonic, cell. 1
Andersen; Hippocampus Book 70 Each axo-axonic cell terminates on approximately 1200 pyramidal cell axon initial segments, and each initial segment is innervated by 4 to 10 axo-axonic cells. 0
Andersen; Hippocampus Book 70 Because most of the excitatory input to the O-LM cells appear to arise from recurrent collaterals of the pyramidal cells, this class of interneuron exhibits activity in the distal dendrites of pyramidal cells in a disynaptic, feedback manner. 0
Andersen; Hippocampus Book 71 One of the distinguishing features of the connectivity of the hippocampus is that most of its synaptic inputs arise from within its own boundaries. 1
Andersen; Hippocampus Book 71 CA3 and CA2 are heavily innervated by collaterals of their own axons (i.e. associational connections) and from axons of the contralateral CA3 and CA2. 0
Andersen; Hippocampus Book 71 CA1 receives its heaviest input from CA3. 0
Andersen; Hippocampus Book 71 There are relatively few of the extrinsic inputs to the hippocampus. 0
Andersen; Hippocampus Book 71 Entorhinal innervation of CA3 is mentioned in most studies of the preference at protection. 0
Andersen; Hippocampus Book 71 The preferred path perforates the subiculum and hippocampal fissure en route to the dentate gyrus. 0
Andersen; Hippocampus Book 71 Hippocampal Connections within Neocortex and Amygdaloid Complex 0
Andersen; Hippocampus Book 71 The hippocampus sends projections to and receives projections from numerous other brain regions. 0
Andersen; Hippocampus Book 71 Notwithstanding the extremely important functional relationship between hippocampus and neocortex, it turns out that only selected parts of a hippocampal formation have discrete, monosynaptic connections with neocortex. 0
Andersen; Hippocampus Book 71 The CA3 and CA2 fields of a hippocampus have no known connections within neocortex. 0
Andersen; Hippocampus Book 73 The hippocampus, like a dentate gyrus, received noradrenergic and serotonergic inputs from brainstem nuclei. 2
Andersen; Hippocampus Book 74 Intrinsic Connections: CA3 Associational Connections and Schaffer Collaterals 1
Andersen; Hippocampus Book 74 The major source of input to the hippocampus is the hippocampus in itself. 0
Andersen; Hippocampus Book 74 The CA3 to CA3 associational connections and the CA3 to CA1 Schaffer collateral connections are distinguished by their extensive spatial distribution. 0
Andersen; Hippocampus Book 74 Through their connections, a particular pyramidal cell in CA3 can, in theory, interact with other hippocampal neurons distributed throughout much of the ipsilateral and contralateral hippocampus. 0
Andersen; Hippocampus Book 74 The hippocampal connections, although widely distributed, are nonetheless systematically organized. 0
Andersen; Hippocampus Book 74 All CA3 and CA2 pyramidal cells give rise highly divergent projections to all portions of the hippocampus. 0
Andersen; Hippocampus Book 74 CA3 pyramidal cells gives rise to highly collateralized axons that distribute fibers both within the ipsilateral hippocampus (to CA3, CA2, and CA1), to the same fields in the contralateral hippocampus, and subcortically to the lateral septal nucleus. 0
Andersen; Hippocampus Book 74 CA3 does not project to the subiculum, presubiculum, parasubiculum, or entorhinal cortex. 0
Andersen; Hippocampus Book 75 The associational projections from CA3 to CA3 are organized in a highly systematic fashion. 1
Andersen; Hippocampus Book 77 Subiculum is a Major Output Structure 2
Andersen; Hippocampus Book 77 This subiculum is a major source of efferent projections from the hippocampal formation. 0
Andersen; Hippocampus Book 78 The subiculum reciprocates the entorhinal input. 1
Andersen; Hippocampus Book 80 Hypothalamus Connections: Mammillary Nuclei 2
Andersen; Hippocampus Book 80 The subiculum provides the major input to the mammillary nuclei. 0
Andersen; Hippocampus Book 81 Presubiculum and Parasubiculum 1
Andersen; Hippocampus Book 83 The presubiculum and parasubiculum receive heavy cholinergic input. 2
Andersen; Hippocampus Book 83 The entorhinal cortex is not only the main entry point for much of the sensory information processed by the hippocampal formation, it provides the main conduit for processed information to be relayed back to the neocortex. 0
Andersen; Hippocampus Book 83 The entorhinal cortex is the beginning and end point of an extensive loop of information processing that takes place in the hippocampal formation. 0
Andersen; Hippocampus Book 84 The entorhinal cortex is a site of early, devastating pathology in degenerative diseases such as Alzheimer's disease. 1
Andersen; Hippocampus Book 84 Standard six-layered laminar organization applied to the isocortex. 0
Andersen; Hippocampus Book 84 There are four cellular layers (II, III, V, VI) and two acellular or plexiform layers (I, IV). 0
Andersen; Hippocampus Book 84 Layer 1 -- the most superficial plexiform or molecular layer, which is so poor but rich in transversely oriented fibers. 0
Andersen; Hippocampus Book 84 Layer 2 -- containing mainly medium-sized to large stellate cells in a population of small pyramidal cells that team tend to be grouped in clusters particularly in the lateral entorhinal area. 0
Andersen; Hippocampus Book 84 Layer 3 -- containing cells of various sizes and shapes but predominately pyramidal cells. 0
Andersen; Hippocampus Book 84 Layer 4 -- a cell-free layer located between layers 3 and 5 that is most apparent in portions of the entorhinal cortex. 0
Andersen; Hippocampus Book 84 Layer 5 -- a cellular layer, which can be subdivided into bands. 0
Andersen; Hippocampus Book 84 Layer 6 -- containing a highly heterogeneous population of cells sizes and shapes. They cell density decreases toward the border with the white matter. 0
Andersen; Hippocampus Book 91 The dentate gyrus and the CA3 field of the hippocampus do not project back to the entorhinal cortex. 7
Andersen; Hippocampus Book 93 The major portion of the entorhinal cortex does not contribute projections to the human modal areas of the neocortex. 2
Andersen; Hippocampus Book 93 The bulk of neocortically directed projections from the entorhinal cortex are to higher-order associational and polysensory cortices and not to sensory or motor regions. 0
Andersen; Hippocampus Book 93 Among the cortical areas that do receive entorhinal inputs are the infralimbic, prelimbic, orbitofrontal, agranular insular, perrirhinal, and postrhinal cortices. 0
Andersen; Hippocampus Book 93 The entorhinal cortex receives a number of subcortical inputs. 0
Andersen; Hippocampus Book 93 Whereas some inputs to the entorhinal cortex, such is the monoaminergic and cholinergic inputs, may be viewed as largely modulatory, others such as the input from the amygdala complex, might also provide additional sources of information. 0
Andersen; Hippocampus Book 93 The substantial input to the entorhinal cortex from the amygdaloid complex is presumably conveying information about the emotional state of the organism. 0
Andersen; Hippocampus Book 93 The entorhinal cortex sends feedback projections to the amygdala. 0
Andersen; Hippocampus Book 93 The entorhinal cortex    projects bilaterally    to the striatum,     particularly to the nucleus accumbens    and adjacent parts of the olfactory tubercle. 0
Andersen; Hippocampus Book 93 The entorhinal cortex    receives cholinergic innervation mainly from the septum. 0
Andersen; Hippocampus Book 93 The entorhinal cortex projects back to the septal region. 0
Andersen; Hippocampus Book 93 The entorhinal cortex    receives defuse inputs    from various structures in the hypothalamus. 0
Andersen; Hippocampus Book 94 Summary of the reciprocal connections between the amygdala and the hippocampal formation    and the perrirhinal and parahippocampal cortices. (diagram) 1
Andersen; Hippocampus Book 94 There is no evidence that the entorhinal cortex projects back to the thalamus. 0
Andersen; Hippocampus Book 94 Brain Stem Inputs to the Entorhinal Cortex 0
Andersen; Hippocampus Book 94 The entorhinal cortex    received dopaminergic input    from cells located in the ventral tegmental area. 0
Andersen; Hippocampus Book 94 Serotonergic innervation    arises from the central and dorsal raphe nuclei    and terminates diffusely    in all layers of the entorhinal cortex. 0
Andersen; Hippocampus Book 94 The noradrenergic locus coeruleus    supplies the entorhinal cortex    with diffusely organized noradrenergic input. 0
Andersen; Hippocampus Book 95 A variety of peptides and other chemical markers have been shown to subdivide their populations in GABAergic interneurons. 1
Andersen; Hippocampus Book 95 Another class of substances that appear to mark certain subsets of GABAergic neurons selectively is the family of calcium-binding proteins. 0
Andersen; Hippocampus Book 95 Although the precise function of the various calcium-binding proteins has not been well established, their existence has provided a useful anatomical tool. 0
Andersen; Hippocampus Book 95 When researchers view the stained sections of hippocampus from rat, monkey, and human, it is immediately apparent they are looking at the same brain region. 0
Andersen; Hippocampus Book 95 The entorhinal cortex has many more subdivisions in the monkey and human than in rats;    and the laminar organization is much more distinct in the primate brain. 0
Andersen; Hippocampus Book 96 Although we can address certain issues concerning cell number and distribution in the human brain,    we are unable to say anything about patterns of connectivity in the human hippocampal formation. 1
Andersen; Hippocampus Book 96 In CA1, there are only three times more pyramidal cells in the monkey than in the rat,    whereas there are 35 times more cells in humans than in rats. 0
Andersen; Hippocampus Book 104 Our understanding of the human hippocampus    is necessarily primitive    compared to that of the rat or the monkey. 8
Andersen; Hippocampus Book 104 Molecular biology may someday provide new pathway selective markers that allow comparative studies of the rat, monkey, and human hippocampal formation. 0
Andersen; Hippocampus Book 104 The CA1 field of the hippocampus is thicker in humans than in monkeys; in some regions it is as much as 30 cells thick. 0
Andersen; Hippocampus Book 104 In addition to being thicker, the CA1 pyramidal cell layer takes on a distinctive multi-laminate appearance, with cells of different size and shape predominating at different depths of the layer. 0
Andersen; Hippocampus Book 106 Little is known about the morphology of cells in the human dentate gyrus. 2
Andersen; Hippocampus Book 106 The human entorhinal cortex has attracted considerable attention because of its vulnerability in Alzheimer's disease. 0
Andersen; Hippocampus Book 106 There is little information concerning the organization of connections in the human hippocampal formation owing to the fact that most neuroanatomical tracing techniques require injection of tracers into the living brain. 0
Andersen; Hippocampus Book 106 Magnetic Resonance Imaging of the Human Hippocampal Formation 0
Andersen; Hippocampus Book 106 Grid of 4 mm squares over the medial temporal lobe, which is typical for fMRI. Might expect to have one voxel over the subiculum or perhaps two voxels over the entorhinal cortex. Other voxels would overlap adjacent fields, such as the dentate gyrus and CA3. (diagram) 0
Andersen; Hippocampus Book 106 With the current functional imaging technologies, it is difficult to define specific activations for defined subfields of the hippocampal formation. 0
Andersen; Hippocampus Book 107 Much of a neuroanatomical information available has been gained from studies of the rat. 1
Andersen; Hippocampus Book 107 A variety of models for temporal lobe epilepsy have been advance based on cell degeneration and fiber sprouting in the rat hippocampus. 0
Andersen; Hippocampus Book 107 It would not be surprising if substantial differences exist in the cellular morphology, connectivity, and chemical neuroanatomy of the hippocampal formation    across species. 0
Andersen; Hippocampus Book 108 Summary of the transverse organization of the connections through the hippocampal formation (diagram) 1
Andersen; Hippocampus Book 109 Serial and Parallel Processing in the Hippocampal Formation 1
Andersen; Hippocampus Book 109 A unique feature of the intrinsic hippocampal circuitry is the largely unidirectional organization of the projections that interconnect the various hippocampal regions. 0
Andersen; Hippocampus Book 109 The intrinsic hippocampal circuitry has both serial and parallel projections. 0
Andersen; Hippocampus Book 109 The entorhinal cortex contributes many parallel projections to several fields of the hippocampal formation. 0
Andersen; Hippocampus Book 109 The existence of prominent associational connections in the dentate gyrus, hippocampus, and entorhinal cortex also provides a substrate for polysynaptic activation in hippocampal circuits. 0
Andersen; Hippocampus Book 115 Morphological Development of the Hippocampus 6
Andersen; Hippocampus Book 115 The enormous number of specific interneuronal connections that serve the complex functions of immature CNS are formed during development. 0
Andersen; Hippocampus Book 115 Modern genetic approaches include mutant mice lacking or overexpressing genes important for developmental processes. 0
Andersen; Hippocampus Book 115 Phylogenetic development of the hippocampal formation has demonstrated that it is a form of phylogenetically old cortex, the archicortex, that develops in the medial wall of the telencephalic vesicle. 0
Andersen; Hippocampus Book 115 Owing to the expansion of the cerebral cortex in higher vertebrates, the hippocampal formation is translocated medially  and ventrally into the inferior portion of the lateral ventricle. 0
Andersen; Hippocampus Book 115 As in other organs, it is important to understand the signals governing cell proliferation. 0
Andersen; Hippocampus Book 115 Postmitotic neurons    migrate to their final destination. 0
Andersen; Hippocampus Book 115 Upon arrival in their appropriate structure or layer,    the postmigratory neuroblasts start to develop their processes. 0
Andersen; Hippocampus Book 115 Why do the nonprincipal cells that invade the hippocampus from the ganglionic eminence form such a heterogeneous population of neurons? 0
Andersen; Hippocampus Book 115 To what extent is neuronal activity involved in the differentiation of dendrites, dendritic spines, and synaptic contacts? 0
Andersen; Hippocampus Book 115 The development of major hippocampal connections -- determinants of pathfinding, target layer recognition, and synaptic formation of hippocampal afferents. 0
Andersen; Hippocampus Book 115 Most of our knowledge about cell formation in the rodent hippocampal formation dates back to seminal studies in 1965. 0
Andersen; Hippocampus Book 116 Research has provided descriptions of the origin, the time course of generation, and the laminar distribution of principal neurons, pyramidal neurons, and granule cells. 1
Andersen; Hippocampus Book 116 Stem cells of both pyramidal neurons and granule cells originate from the ventricular germinal layers that are located below the ventricular wall along the CA1 area. 0
Andersen; Hippocampus Book 116 The multiplying neurons directly migrate from the ventricular zone to their final target region. 0
Andersen; Hippocampus Book 116 Except for the CA3 pyramidal cells, the route of migration is short because the hippocampus closely follows the curve of the ventricle. 0
Andersen; Hippocampus Book 116 The pyramidal cell layer of the hippocampus    forms quite early    in the human brain. 0
Andersen; Hippocampus Book 116 In the human brain, the pyramidal cell layer of the hippocampus is formed during the first half of pregnancy. 0
Andersen; Hippocampus Book 116 in the human brain, the CA1 to CA3 regions of the hippocampus can be differentiated as early as during the 16th embryonic week. 0
Andersen; Hippocampus Book 116 Regional differentiation of the hippocampal formation    substantially precedes    that of the neocortex. 0
Andersen; Hippocampus Book 116 The formation of the granule cell layer of the dentate gyrus    differs in many respects    from that of the pyramidal cell layer of the hippocampus. 0
Andersen; Hippocampus Book 116 The generation of granule cells   lasts a much longer time    than that of pyramidal neurons. 0
Andersen; Hippocampus Book 116 There is substantial evidence that the generation of granule cells    continues long into the postnatal period    and, at a reduced level, into adulthood. 0
Andersen; Hippocampus Book 116 In rats, the time span though of cell generation is approximately 3 times longer than that of pyramidal neurons and is likely to continue for the rest of the animal's life. 0
Andersen; Hippocampus Book 116 In humans,     granule cell formation    lasts more than 30 weeks,    beginning at approximately the 13th embryonic week. 0
Andersen; Hippocampus Book 117 There is evidence for adult neurogenesis in the human dentate gyrus. 1
Andersen; Hippocampus Book 117 The route of migration    of the postmitotic granule cells    is much longer    than that of pyramidal neurons. 0
Andersen; Hippocampus Book 117 Postmitotic granule cells must migrate    from the ventricular germinal layer   along the already formed hippocampus    where they form the cup-shaped dentate gyrus    that surrounds the tip of CA3.    0
Andersen; Hippocampus Book 117 The enduring cell proliferation    in the hilar region    mainly represents local generation    of granule cells. 0
Andersen; Hippocampus Book 117 Proliferating cells persists in the hilar region during the entire period of granule cell neurogenesis, and persisting hilar stem cells may also form new neurons during adulthood. 0
Andersen; Hippocampus Book 117 There is little morphological variability among granule cells even though they may be located in different places in the granule cell layer and may be born at different time points. 0
Andersen; Hippocampus Book 117 The morphological uniformity    of granule cells    leads to the assumption that all granule cells    originate from the same stem cell population. 0
Andersen; Hippocampus Book 117 Most of the granule cells display similar features in the rodent and primate dentate gyrus. 0
Andersen; Hippocampus Book 118 Epileptic seizures appear to lead to an increased number of granule cells   with basal dendrites in the human dentate gyrus. 1
Andersen; Hippocampus Book 118 Dentate granule cells in different mammalian species form a largely homogeneous neuronal population. 0
Andersen; Hippocampus Book 118 Dendritic morphology of dentate granule cells in different mammalian species may be modified to some extent depending on the local environment or pathological factors. 0
Andersen; Hippocampus Book 118 Local circuit neurons of the hippocampal formation     differ from the principal cells    in both their morphological and developmental features. 0
Andersen; Hippocampus Book 118 In contrast to the morphologically uniform    granule cells and pyramidal neurons,    local circuit neurons of the hippocampal formation    form a heterogeneous population. 0
Andersen; Hippocampus Book 118 Even the classic basket cell can be subdivided into five types     based on differences in location and dendritic arborization. 0
Andersen; Hippocampus Book 118 In addition to dendritic morphology,    differences in axonal projections    also distinguish subpopulations of local circuit neurons    in both the dentate gyrus    and the hippocampus proper. 0
Andersen; Hippocampus Book 120 In the neocortex,    cell layers are formed in an inside-out manner;    i.e. early-generated neurons form deeper layers,   whereas superficial layers are established by cells late in ontogenetic development. 2
Andersen; Hippocampus Book 120 As in the neocortex, the hippocampus follows a similar inside-out migration. 0
Andersen; Hippocampus Book 120 Migration processes are under fairly strict genetic control. 0
Andersen; Hippocampus Book 120 When describing the development of neuronal connections, it is useful to distinguish at least three processes:    (1) axonal pathfinding, (2) target recognition,    (3) synapse formation. 0
Andersen; Hippocampus Book 120 There is substantial and increasing evidence that a variety of molecules are involved in the development of neuronal connection. 0
Andersen; Hippocampus Book 121 The various semaphorins and their receptors; the plexins, and the ephrin family of tyrosine kinases and their ligands,    contribute to establishing hippocampal circuitry. 1
Andersen; Hippocampus Book 121 Entorhinal Connections 0
Andersen; Hippocampus Book 121 Neuroanatomists have been intrigued by the unique course of the entorhino-hippocampal projection,    which perforates the subiculum and hippocampal fissure    en route to the dentate gyrus. 0
Andersen; Hippocampus Book 122 The growth of the neuronal fibers along CR cell axons is likely to be controlled by a variety of repulsive and attractive molecules. 1
Andersen; Hippocampus Book 122 How do entorhinal fibers recognize their target layer? Current evidence strongly suggests that components of the extracellular matrix play an important part in the segregation of hippocampal afferents. 0
Andersen; Hippocampus Book 123 Secreted molecules such as the semaphorins, membrane-bound receptors, extracellular matrix components, and a template formed by CR cell axons are likely to be involved in the directed growth and layer-specific termination of entorhinal fibers. 1
Andersen; Hippocampus Book 123 Target cells are unlikely to be involved in pathfinding of entorhinal axons and target layer recognition. 0
Andersen; Hippocampus Book 123 Many questions concerning the layout-specific termination of entorhinal fibers remain open at present. 0
Andersen; Hippocampus Book 123 Commissural fibers, originating from CA3 pyramidal neurons and hilar mossy cells, project via the hippocampal commissure to the contralateral hippocampus and intake gyrus. 0
Andersen; Hippocampus Book 124 Since the commissural fibers arrive relatively late in the hippocampus and dentate gyrus, the pioneered neurons may not be required, because the target cells, the principal neurons, are already present at that time and have already grown a dendritic arbor. 1
Andersen; Hippocampus Book 124 Whereas the entorhinal fibers require pioneer neurons, the commissural afferents establish contacts directly with principal cell dendrites. 0
Andersen; Hippocampus Book 124 Little is known about the molecules involved in pathfinding and target recognition of commissural fibers. 0
Andersen; Hippocampus Book 125 The septohippocampal projection consists of two parts: a cholinergic one and a GABAergic one. 1
Andersen; Hippocampus Book 125 The cells of origin for both parts of the septohippocampal projection are located in the medial septal nucleus/diagonal band complex (MSDP). 0
Andersen; Hippocampus Book 125 The hippocampus-septal projection develops relatively early and terminates in the medial septum. 0
Andersen; Hippocampus Book 125 The early termination of the hippocampo-septal projection in the medial septal nucleus has led to the hypothesis that the early formed hippocampo-septal projection serves as a template by which septohippocampal fibers find their way to the hippocampus. 0
Andersen; Hippocampus Book 125 It has been shown that growth cones of septohippocampal fibers grow along hippocampo-septal axons. 0
Andersen; Hippocampus Book 125 Septohippocampal cholinergic fibers are found in all layers of the hippocampal formation, but are certainly more concentrated in cell body layers. 0
Andersen; Hippocampus Book 125 Septohippocampal GABAergic projection cells display a high target cells specificity, terminating almost exclusively on GABAergic interneurons in the hippocampus. 0
Andersen; Hippocampus Book 126 The septal cholinergic fibers establish contacts with both principal neurons and interneurons, and they are contacts are on cell bodies, dendritic shafts, and spines. 1
Andersen; Hippocampus Book 126 Nerve growth factor (NGF) is synthesized by GABAergic hippocampus neurons, which are distributed over all hippocampal layers. 0
Andersen; Hippocampus Book 126 Different cellular and molecular factors, probably being effected only during certain development time windows, are involved in the formation of the different projections to the hippocampus. 0
Andersen; Hippocampus Book 126 When describing the formation of a pathway, it is useful to distinguish between axonal pathfinding, target recognition, and synapse formation. 0
Andersen; Hippocampus Book 127 For pathfinding and target recognition,    pioneer neurons provide a template by an early-formed projection. 1
Andersen; Hippocampus Book 127 Membrane-bound and soluble molecules and components of the extracellular matrix seem to play a role at different times of development. 0
Andersen; Hippocampus Book 127 A variety of ligand-receptor interactions, by their repulsive or attractive effects, may guide the growth cone of a growing axon in the target region. 0
Andersen; Hippocampus Book 127 Extracellular matrix molecules may be essential for segregation of fiber systems in the hippocampus. 0
Andersen; Hippocampus Book 127 Studies of synapse formation is a rapidly-developing field. 0
Andersen; Hippocampus Book 127 Mechanisms leading to new contacts or changes in the shape of synapses or spines may not only be effective during development but may also underlie plastic processes in the adult organism. 0
Andersen; Hippocampus Book 127 Researchers have observed new spines formed during the development of long term potentiation (LTP). 0
Andersen; Hippocampus Book 127 Researchers have shown that estrogen application induces new spines on CA1 pyramidal cell dendrites, an effect likely caused by estrogen acting primarily on CA3 pyramidal cells and inducing the sprouting of Schaffer collaterals to CA1 pyramidal neurons. 0
Andersen; Hippocampus Book 127 Research studies have shown that estrogens synthesized in the hippocampus are important for hippocampal synaptic plasticity. 0
Andersen; Hippocampus Book 127 Future studies will help establish whether estrogen-induced plastic changes in spine synapses are specific for hippocampal neurons or are a more general phenomenon occurring at many synapses in the central nervous system. 0
Andersen; Hippocampus Book 127 Differentiation of pyramidal neurons and granule cells continues for a relatively long period in rodents and primates. 0
Andersen; Hippocampus Book 127 Spine density increases until the time of sexual maturation. 0
Andersen; Hippocampus Book 127 In humans, spine density and total dendritic length    of CA1 pyramidal neurons    increase    until at least the third postnatal year. 0
Andersen; Hippocampus Book 127 In contrast to the long-term differentiation of principal cells, local circuit neurons in the primate hippocampal formation but to a fast. 0
Andersen; Hippocampus Book 128 Arrival of afferents at the rat hippocampus formation continues with the development of their target cells. 1
Andersen; Hippocampus Book 128 In both rodents and humans    the late development of the intrahippocampal associational connections    may influence the maturation of the entire hippocampal network. 0
Andersen; Hippocampus Book 133 Structural and Functional Properties of Hippocampal Neurons 5
Andersen; Hippocampus Book 133 Understanding the function of the hippocampus includes the unique morphological and physiological properties of the great variety of neurons. 0
Andersen; Hippocampus Book 133 Although long term potentiation was first described in the dentate gyrus, most of the studies in the decades that followed in its original description have focused on the CA1 region. 0
Andersen; Hippocampus Book 134 Studies are CA1 are more numerous in adjacent CA3 because it is generally easier to keep cells in this region are alive and healthy in slice preparations. 1
Andersen; Hippocampus Book 134 CA1 pyramidal neurons have been the focus of several studies of dendritic integration because of the large primary apical dendrite, from which dendritic patch-clamp recordings can be obtained routinely. 0
Andersen; Hippocampus Book 134 Hippocampus studies have contributed to tremendous advances in understanding synaptic transmission, integration, and plasticity in the CNS. 0
Andersen; Hippocampus Book 134 To elaborate label branching dendritic trees emerged from the pyramid-shaped soma of CA1 neurons. 0
Andersen; Hippocampus Book 134 Basal dendrites occupy the stratum oriens,    and the apical dendrites occupy the stratum radium and stratum lacunosum-moleculare. 0
Andersen; Hippocampus Book 134 The combined length of all CA1 dendritic branches is 12.0 to 13.5 mm. 0
Andersen; Hippocampus Book 134 CA1 dendrites studied with spines. 0
Andersen; Hippocampus Book 134 Along the length    of the primary apical dendrite,    several dendritic branches   emerge obliquely    in the stratum radiatum. 0
Andersen; Hippocampus Book 134 Oblique dendrites    branch no more than a few times,    and with a typical branch bifurcating just once    at a location close to its origin from the apical trunk. 0
Andersen; Hippocampus Book 134 After the primary apical trunk enters the stratum lacunosum-moleculare    the apical dendrites continue to branch,    forming a structure called the apical tuft. 0
Andersen; Hippocampus Book 134 Emerging from the base of the pyramidal soma    are two to eight dendrites,    forming a basal dendritic tree with about 40 terminal segments. 0
Andersen; Hippocampus Book 134 Many other organelles found in the cell body    extend into the proximal apical dendrites of CA1 neurons.    These include structures such as the smooth endoplasmic reticulum (SER) and the Golgi apparatus. 0
Andersen; Hippocampus Book 134 Microtubules, neurofilaments, and actin are prominent and serve transport and motility functions, and are likely to be important in synaptic plasticity. 0
Andersen; Hippocampus Book 134 A network of smooth endoplasmic reticulum is also present in dendrites, where it is likely to serve important functions in calcium buffering and release. 0
Andersen; Hippocampus Book 134 The smooth endoplasmic reticulum forms a continuous reticulum, which can extend into dendritic spines. 0
Andersen; Hippocampus Book 134 Mitochondria are also numerous in dendrites and are often associated with the smooth endoplasmic reticulum. 0
Andersen; Hippocampus Book 134 Dendritic mitochondria likely contribute to calcium handling in addition to serving as the primary energy source. 0
Andersen; Hippocampus Book 135 CA1 dendritic morphology, spines, and synaptic inputs and outputs. (diagram) 1
Andersen; Hippocampus Book 136 Ribosomes are present in CA1 dendrites, where they are usually clustered in the form of polyribosomes. 1
Andersen; Hippocampus Book 136 CA1 pyramidal neurons are covered with about 30,000 dendritic spines. 0
Andersen; Hippocampus Book 136 The dendritic spines     studding the surface of CA1 dendrites    exhibit a broad range    of size and morphological complexity. 0
Andersen; Hippocampus Book 136 Thin spines are long, narrow protrusions terminating in a small, bulbous head. 0
Andersen; Hippocampus Book 136 Sessile spines are long, narrow protrusions that do not terminate in a head. 0
Andersen; Hippocampus Book 136 Mushroom spines have a narrow neck and a large, bulbous head. 0
Andersen; Hippocampus Book 136 Branched spines consists of a neck that branches and terminates in two bulbous heads, each of which receives synaptic input from different axons. 0
Andersen; Hippocampus Book 136 Spine structure is not static but may change in response to neurotransmitter activation    or environmental    and hormonal signals. 0
Andersen; Hippocampus Book 136 Growth of new spines    and changes in the structure of existing spines    are possible substrates of synaptic plasticity in the hippocampus. 0
Andersen; Hippocampus Book 137 Spines also contained numerous organelles, including smooth endoplasmic reticulum (SER). 1
Andersen; Hippocampus Book 137 The presence of a large number of molecules and organelles in spines,    together with the separation that the spine neck provides from the dendritic shaft and other spines,    has led to the hypothesis that spines function as isolated molecular compartments. 0
Andersen; Hippocampus Book 137 A prominent feature of almost all spines throughout the nervous system is a postsynaptic density (PSD),    an electron-dense thickening of the postsynaptic membrane. 0
Andersen; Hippocampus Book 137 The PSD is located adjacent to the presynaptic bouton associated with the spine. 0
Andersen; Hippocampus Book 137 Functionally, the PSD is a biochemical specialization that allows numerous molecules (e.g. receptors,    kinases,    cytoskeletal elements) to be associated in a structured array at the synapse. 0
Andersen; Hippocampus Book 137 NMDA receptors, which mediate a slow synaptic current    blocked in a voltage-dependent manner,    occupy a disk-like space near the center of the PSD. 0
Andersen; Hippocampus Book 137 AMPA receptors, which mediate a fast synaptic current, are distributed more evenly    throughout the PSD. 0
Andersen; Hippocampus Book 137 Individual excitatory synapses on CA1 neurons    vary considerably in their expression of AMPA and NMDA receptors. 0
Andersen; Hippocampus Book 137 Whereas the number of NMDA receptors is relatively invariant,    a tremendous range exists in the number of AMPA receptors at individual synapses. 0
Andersen; Hippocampus Book 137 CA1 neurons receive input from both excitatory and inhibitory presynaptic neurons. 0
Andersen; Hippocampus Book 137 The principal excitatory inputs to CA1 neurons arrive from the entorhinal cortex and CA3 pyramidal neurons. 0
Andersen; Hippocampus Book 137 Inputs from pyramidal neurons in the entorhinal cortex    project to CA1 neurons    via the perforant path (PP). 0
Andersen; Hippocampus Book 137 Inputs from CA3 pyramidal neurons on both sides of the brain    form the Schaffer collateral/commissural system (SC). 0
Andersen; Hippocampus Book 138 Numerous inhibitory neurons also target CA1 pyramidal neurons.    Some of these interneurons target the soma and axon, and others target dendrites. 1
Andersen; Hippocampus Book 138 CA1 pyramidal neurons also receive neuromodulatory inputs from a number of subcortical nuclei. 0
Andersen; Hippocampus Book 138 A large input arriving from the septum    contains cholinergic afferents. 0
Andersen; Hippocampus Book 138 Projections from the locus coeruleus contain noradrenergic inputs. 0
Andersen; Hippocampus Book 138 Raphe nuclei projection contains serotonergic inputs. 0
Andersen; Hippocampus Book 138 The ventral tegmental area sends dopaminergic afferents to the hippocampus. 0
Andersen; Hippocampus Book 138 CA1 pyramidal neurons    express numerous receptor subtypes    for each of the neuromodulators. 0
Andersen; Hippocampus Book 138 A single axon emanates from the pyramidal soma of CA1 pyramidal neurons and projects through the stratum oriens. 0
Andersen; Hippocampus Book 138 CA1 axons    branch extensively,    forming collaterals with several targets,    both within and beyond the hippocampus. 0
Andersen; Hippocampus Book 138 Unlike CA3 pyramidal neurons, CA1 cells do not make many connections among themselves. 0
Andersen; Hippocampus Book 138 CA1-interneuron connectivity is much higher than CA3, and the strength of excitatory postsynaptic potentials (EPSPs) on interneurons is powerful. 0
Andersen; Hippocampus Book 138 The most significant intrahippocampal projection of CA1 neurons is to pyramidal neurons in the subiculum. 0
Andersen; Hippocampus Book 138 The subiculum forms a powerful output of the hippocampus. 0
Andersen; Hippocampus Book 138 CA1 axons collateralized extensively in the subiculum but form a topological projection. 0
Andersen; Hippocampus Book 139 The CA1 axon, which has a diameter of less than 1 µ, has numerous en passant and terminal synaptic specializations along its length. 1
Andersen; Hippocampus Book 141 CA1 pyramidal neurons, like most neurons in the brain, have long and extensively branching dendrites. 2
Andersen; Hippocampus Book 144 Detailed compartmental modeling of CA1 neurons suggests that functional coupling between the soma and distal dendrites is limited. 3
Andersen; Hippocampus Book 144 Attenuation of synaptic potentials and CA1 dendrites. 0
Andersen; Hippocampus Book 144 Mechanisms of compensation for synaptic attenuation and CA1 dendrites. 0
Andersen; Hippocampus Book 145 Passive Versus Active Dendrites 1
Andersen; Hippocampus Book 146 Action potentials from CA1 neurons coupled by gap junctions have been implicated. 1
Andersen; Hippocampus Book 146 Dendrites of CA1 pyramidal neurons are capable of generating active responses owing to the presence of voltage-gated channels. 0
Andersen; Hippocampus Book 146 Studies have led to the hypothesis that action potentials might be initiated in dendrites. 0
Andersen; Hippocampus Book 146 The site of action potential of initiation has been narrowed to a region near their first node of Ranvier in the axon. 0
Andersen; Hippocampus Book 146 Following their initiation in the axon, action potentials and they did dendritic tree of CA1 neurons. 0
Andersen; Hippocampus Book 146 Add 300 µ, the back-projecting action potential amplitude is about half of the somatic amplitude. 0
Andersen; Hippocampus Book 146 Even for modest firing frequencies such as 20 Hz, the action potential amplitude, measured about 300 µ from the soma,    attenuates to less than half of its amplitude at lower frequencies. 0
Andersen; Hippocampus Book 152 Functional implication of voltage-gated channels in CA1 dendrites: Synaptic Integration and Plasticity 6
Andersen; Hippocampus Book 152 Dendrites are able to generate a variety of active responses,    including back-propagating action potentials    and dendritic Na+ and Ca2+ spikes. 0
Andersen; Hippocampus Book 152 The CA1 pyramidal neuron is arguably the most extensively studied neuron with respect to resting membrane properties,    dendritic function,    and synaptic integration. 0
Andersen; Hippocampus Book 152 Voltage attenuation in dendrites is predicted to be enormous for the near-passive condition. 0
Andersen; Hippocampus Book 152 The neuron appears to compensate for voltage attenuation in dendrites    by at least two key mechanisms:    (1) synapse conductance scaling,    and (2) excitable dendrites containing myriad voltage-gated channels. 0
Andersen; Hippocampus Book 153 One emergent property of the complexity of the CA1 dendritic tree appears to be coincidence detection for perforant-path and Schaffer-collateral synaptic inputs. 1
Andersen; Hippocampus Book 153 CA3 Pyramidal Neurons 0
Andersen; Hippocampus Book 153 CA3 pyramidal neurons have been studied extensively,    because of the unique functional specializations formed by the mossy fiber inputs from the dentate gyrus    and because of the extensive axon collaterals    between CA3 neurons,    which create a highly interconnected and excitable network. 0
Andersen; Hippocampus Book 155 CA3 pyramidal neurons    receive three prominent forms    of excitatory synaptic input --    (1) mossy fiber input from dentate granule cells,    (2) input from entorhinal cortex via the perforant path,    (3) from axons of other CA3 neurons. 2
Andersen; Hippocampus Book 155 The commissural/associational inputs to CA3 are numerous and originate from CA3 neurons on both sides of the brain. 0
Andersen; Hippocampus Book 155 The extensive network of recurrent collaterals    has led to the postulate that the CA3 region    may function as an autoassociative network    involved in memory storage and recall. (Rolls) 0
Andersen; Hippocampus Book 155 A side effect of the extensive interconnectivity    is that the CA3 network    is highly excitable    and prone to the seizure activity    when inhibition is suppressed. 0
Andersen; Hippocampus Book 155 CA3 neurons also receive cholinergic input from the medial septal nucleus. 0
Andersen; Hippocampus Book 156 A comparison of the properties of mossy fiber synaptic transmission to AMPA receptor properties in CA3 dendrites suggest that a typical quantal event would consist of 35 AMPA receptors being activated by a single quantum of glutamate. 1
Andersen; Hippocampus Book 156 The high density of AMPA receptors    and the large number of synaptic specializations    on each thorny excrescence    accounts for the large size and variability    of unitary mossy fiber synaptic currents. 0
Andersen; Hippocampus Book 156 CA3 pyramidal neurons    also receive substantial innervation    from inhibitory interneurons. 0
Andersen; Hippocampus Book 156 In addition to the somatic and axonal inhibition,    which presumably limits action potential initiation,    a number of interneurons target CA3 dendrites. 0
Andersen; Hippocampus Book 156 The dendritic inhibition    limits the initiation    and enhances termination    of dendritic calcium spikes. 0
Andersen; Hippocampus Book 156 Each CA3 pyramidal neuron gives rise to a single axon,    which projects bilaterally to CA3,    CA2,    and CA1 regions,   as well as to the lateral septal nucleus. 0
Andersen; Hippocampus Book 156 Individual axons are thin and myelinated with abundant en passant boutons or varicosities. 0
Andersen; Hippocampus Book 156 CA3 axons    project primarily to the CA1 region    but also collateralize extensively    within CA3. 0
Andersen; Hippocampus Book 156 The total length of the CA3 collaterals in the ipsilateral hippocampus has been estimated at 150 to 300 mm. 0
Andersen; Hippocampus Book 156 Boutons are located approximately every 4 µ along the CA3 axons, but boutons are distributed unevenly. 0
Andersen; Hippocampus Book 156 Estimates of the total number of synapses formed by a single axon in the ipsilateral hippocampus range from 15,000 to 60,000. 0
Andersen; Hippocampus Book 156 A subset of CA3 axon boutons contacts interneurons. 0
Andersen; Hippocampus Book 156 As in CA1, CA3 pyramidal cell-to-interneuron synapses are powerful enough that a single axon is capable of producing an action potential in postsynaptic interneurons. 0
Andersen; Hippocampus Book 156 A small number of CA3 neurons (~20%) may make multiple synapses on a single CA1 cell. 0
Andersen; Hippocampus Book 156 Although bursting occurs in CA1 pyramidal neurons,    bursting is more prominent in CA3,    and is considered a hallmark feature of CA3 pyramidal neurons. 0
Andersen; Hippocampus Book 157 Bursts in CA3 neurons typically comprise several action potentials riding atop a depolarizing waveform. 1
Andersen; Hippocampus Book 157 Each burst is an "all or nothing" event lasting approximately 30 to 50 ms, with the frequency of action potentials in the range of 100 to 300 Hz. 0
Andersen; Hippocampus Book 157 Bursts can be triggered in several ways in CA3 neurons. 0
Andersen; Hippocampus Book 157 One mechanism for burst generation is entirely intrinsic to the neuron and does not require synaptic connectivity. 0
Andersen; Hippocampus Book 157 In some cases bursts occur spontaneously. 0
Andersen; Hippocampus Book 157 The most robust bursts are generated in CA3 neurons    when the entire network becomes synchronously active,    usually in response to suppression of synaptic inhibition. 0
Andersen; Hippocampus Book 157 The entire network becoming synchronously active    is a hallmark of seizure activity in cortical networks. 0
Andersen; Hippocampus Book 157 Intrinsic conductance can generate bursts that are likely to serve as an important signals in a normally functioning network,    whereas massive, synchronous glutamate release contributes to synchronous bursting    during hippocampal seizures. 0
Andersen; Hippocampus Book 157 Because CA3 pyramidal neurons    generate seizures,    they have been extensively studied as the possible pacemakers of interictal epileptiform activity in a variety of animal models of electrographic seizures. 0
Andersen; Hippocampus Book 157 There is good evidence that network bursts are terminated by depletion of glutamate-containing synaptic vesicles during the giant EPSPs that drive the PDS. 0
Andersen; Hippocampus Book 158 Passive models CA3 pyramidal neurons predict large attenuation of EPSPs between the dendrites and the soma. 1
Andersen; Hippocampus Book 158 Dendritic attenuation is likely to be overcome, at least in part, by the presence of voltage-gated conductances in the dendrites. 0
Andersen; Hippocampus Book 159 Because CA3 pyramidal cells lack a large primary apical dendrite such as found in CA1, studies of dendritic excitability and ion channels in CA3 dendrites have lagged behind those in CA1. 1
Andersen; Hippocampus Book 159 Little is known about the identities and properties of specific ion conductance is in the dendrites of CA3 pyramidal neurons. 0
Andersen; Hippocampus Book 159 Although much of what we know about dendritic excitability in CA3 has been inferred from a relatively small number of dendritic recordings and calcium imaging, some interesting computer models have been developed for CA3 neurons. 0
Andersen; Hippocampus Book 159 The subiculum plays an important role in the hippocampal formation, as it receives convergent input from numerous sources and constitutes a major output of the hippocampus. 0
Andersen; Hippocampus Book 159 The pronounced tendency of neurons in the subiculum region to fire bursts of action potentials has led to considerable interest in understanding the cell physiology of these neurons. 0
Andersen; Hippocampus Book 159 Almost all principal neurons in the subiculum have a typical pyramidal morphology, with apical dendrites extending into the molecular layer. 0
Andersen; Hippocampus Book 159 As in CA1, the dendrites of subiculum pyramidal neurons are studied with spines. 0
Andersen; Hippocampus Book 159 Little is known about the distribution of the numerous cortical and subcortical inputs to the dendritic trees of subiculum pyramidal neurons. 0
Andersen; Hippocampus Book 159 Two of the most prominent inputs to subiculum include topological projections from CA1 and entorhinal cortex. 0
Andersen; Hippocampus Book 159 Among the subcortical structures projecting to the subiculum are the thalamic nucleus and weak cholinergic projections from the septal nucleus. 0
Andersen; Hippocampus Book 159 Modulatory inputs from the brainstem also innervate the subiculum, including the locus coeruleus (noradrenergic), ventral tegmental area (dopaminergic), and raphe nuclei (serotonergic). 0
Andersen; Hippocampus Book 159 In addition to a direct input from the entorhinal cortex, the subiculum receives inputs from many of the same cortical areas that project to the entorhinal cortex. 0
Andersen; Hippocampus Book 159 Almost nothing is known about the inhibitory interneurons and their targeting of pyramidal neurons in the subiculum. 0
Andersen; Hippocampus Book 160 Axons of the subiculum pyramidal neurons collateralize extensively in the subiculum as well as projecting out of the subiculum. 1
Andersen; Hippocampus Book 160 Pyramidal neurons with deeper cell bodies in the subiculum tend to form vertically oriented columns of local collaterals, whereas superficial pyramidal neurons exhibit a greater horizontal spread (towards CA1 and EC) in their local axon collaterals. 0
Andersen; Hippocampus Book 160 Projecting axon collaterals of the subiculum target a number of cortical and subcortical structures. They do not project back to CA1 but do project to the entorhinal cortex and the pre- and parasubiculum. 0
Andersen; Hippocampus Book 160 Connections are organized such that subiculum projects back to the same regions of the entorhinal cortex from which it receives input 0
Andersen; Hippocampus Book 160 Among the other numerous targets of the subiculum are the medial prefrontal cortex, anterior olfactory nucleus, septal complex, mammilary nuclei, nucleus accumbens, olfactory tubercle, several thalamic nuclei, and the amygdaloid complex. 0
Andersen; Hippocampus Book 160 A prominent feature of the firing patterns of subicular pyramidal neurons is action potential bursting. 0
Andersen; Hippocampus Book 160 Bursting is much more prominent in this a big killer and than in CA1. 0
Andersen; Hippocampus Book 160 Pyramidal cells in the subiculum have been shown to fall into two broad physiological categories: bursting cells and regular-spiking cells. 0
Andersen; Hippocampus Book 161 It has been shown that bursting cells project preferentially to the presubiculum and parasubiculum, whereas regular-spiking cells project preferentially to the entorhinal cortex. 1
Andersen; Hippocampus Book 162 Another important feature of pyramidal neurons in the subiculum is their ability to generate subthreshold membrane potential oscillations in the theta frequency range of 5 to 9 Hz. 1
Andersen; Hippocampus Book 162 Subicular pyramidal cells also participate in synaptically mediated oscillations in the gamma frequency range of 20 to 50 Hz. 0
Andersen; Hippocampus Book 162 Bursting neurons in subiculum fire doublets of action potentials during oscillations, which likely promote the spread of network activity in the gamma range. 0
Andersen; Hippocampus Book 162 Dentate Granule Neurons 0
Andersen; Hippocampus Book 162 The main cell type of the dentate gyrus is the granule cell. 0
Andersen; Hippocampus Book 162 The granule cells neurons of the dentate gyrus have been studied extensively, in part because they were the first to be shown to exhibit LTP and in part because they receive spatially segregated synaptic inputs on different regions of their dendrites. 0
Andersen; Hippocampus Book 162 Granule cells were the first cell type in which it was shown that mRNA could be translated into proteins in dendrites, which has significant implications for plasticity and learning. 0
Andersen; Hippocampus Book 163 The granule cells of the dentate gyrus comprise a small, ovoid cell body with a single, approximately comical dendritic tree. 1
Andersen; Hippocampus Book 163 The granule cells lie in densely packed, columnar stacks beneath the relatively cell-free molecular layer and cell-rich polymorphic layer. 0
Andersen; Hippocampus Book 163 Granule cell dendrites all extended into the molecular layer and terminate near the hippocampal fissure. 0
Andersen; Hippocampus Book 163 Like pyramidal neurons, the dendrites of granule cells are heavily studied with spines. 0
Andersen; Hippocampus Book 163 The available data suggest that granule cells have between 5630 and 3600 spines. 0
Andersen; Hippocampus Book 163 Dentate granule cell dendritic morphology, spines, and synaptic inputs and outputs. (diagram) 0
Andersen; Hippocampus Book 178 Inhibitory Interneuron Diversity (diagram) 15
Andersen; Hippocampus Book 179 Morphological Classification of Hippocampal Interneurons (table) 1
Andersen; Hippocampus Book 179 All local circuit inhibitory interneurons synthesize and release GABA as their primary neurotransmitter. 0
Andersen; Hippocampus Book 179 Anatomically, interneurons represent one of the most diverse populations in the mammalian CNS. 0
Andersen; Hippocampus Book 179 Inability to classify interneurons neatly into functional anatomical sub-populations. 0
Andersen; Hippocampus Book 179 Mapping of axonal arbors to specific domains across the dendritic trees of their targets and the position the dendrites in specific hippocampal subfields have provided important clues to specific functional roles played by various interneurons subtypes. 0
Andersen; Hippocampus Book 179 Interneurons with axons that innervate either pyramidal cell soma or axon initial segments (basket cells, chandelier cells, axo-axonic cells) almost certainly regulate the local generation of action potentials. 0
Andersen; Hippocampus Book 179 Inhibition arriving at dendritic locations likely has little direct influence over somatic action potential generation but may strongly influence local dendritic integration, shunt excitatory inputs on their way to the soma, or regulate dendritic spike initiation and/or propagation. 0
Andersen; Hippocampus Book 179 Perhaps one of the most useful characterizations of interneuron subtypes has been based on neurochemical content. 0
Andersen; Hippocampus Book 179 Neurochemically identical cells can have surprisingly different functional properties. 0
Andersen; Hippocampus Book 180 Characterization of interneurons based on function has proven to be problematic. The classic subdivisions were originally based solely on action potential firing patterns (e.g. fast spiking versus regular spiking). 1
Andersen; Hippocampus Book 180 Action potential generation results from the combined activity of numerous voltage-gated channels, with each channel type potentially having a unique expression pattern throughout the interneuron subpopulation that imparts subtle characteristics to action potential firing. 0
Andersen; Hippocampus Book 181 Neurochemical markers used to classify hippocampal interneurons (table) 1
Andersen; Hippocampus Book 181 Subdivisions of interneurons based on responses to neuromodulators, properties of intrinsic currents and conductances, or expressions of ligand-gated channels have all had limited success. 0
Andersen; Hippocampus Book 181 Interneurons are excited or inhibited by a bewildering number of combinations of modulators, and when these properties are mapped onto their respective anatomical properties, a staggering number of subpopulations may exist. 0
Andersen; Hippocampus Book 181 The list of synapses that demonstrate facilitation or depression has become increasingly lengthy. 0
Andersen; Hippocampus Book 181 CA1 pyramidal cell-mediated feedback excitation of interneurons. 0
Andersen; Hippocampus Book 181 Whether a particular synapse demonstrates short-term depression or facilitation may be developmentally regulated. 0
Andersen; Hippocampus Book 181 Dendritic Morphology 0
Andersen; Hippocampus Book 181 Despite representing only ~10% of the total hippocampal neuron population, inhibitory interneurons have highly variable morphologies even within distinct subpopulations. 0
Andersen; Hippocampus Book 181 Cells of a given neurochemical subclass can have dendrites that are organized in a widely heterogeneous orientation. 0
Andersen; Hippocampus Book 182 Inhibitory interneuron neurochemistry in dendritic morphology.    A large difference in the absolute and relative numbers of excitatory and inhibitory synapses terminating on dendrites. (diagram) 1
Andersen; Hippocampus Book 182 Arguably the largest of all the inhibitory interneuron subpopulations, the PV-containing, fast-spiking basket cells are found throughout the hippocampal formation. 0
Andersen; Hippocampus Book 182 Among interneurons, PV-containing cells have the most elaborate dendrites, which on average measure >4 mm in their full extent. 0
Andersen; Hippocampus Book 182 PV-containing interneurons have on average 5 primary dendrites that arise from the soma and run radiantly through the stratum oriens or through the stratum radiatum into the stratum lacunosum-moleculare making infrequent branches. 0
Andersen; Hippocampus Book 182 Although PV-containing interneurons have the largest dendritic tree of all interneuron types, these cells demonstrate large variation in individual cell size, with a more than twofold variation in the range of dendritic length. 0
Andersen; Hippocampus Book 183 One special class of the inhibitory interneurons project out of the hippocampus to the medial septum. 1
Andersen; Hippocampus Book 183 CR-containing interneurons can be subdivided into at least two classes based on morphology: a spiny type in a spine-free type. In the CA1 subfield only spine-free CR-containing interneurons are found, whereas both classes are found in CA3. 0
Andersen; Hippocampus Book 183 Dendritic Spines 0
Andersen; Hippocampus Book 183 The conspicuous absence of dendritic spines on most interneuron types undoubtably has a major impact on their computational properties. 0
Andersen; Hippocampus Book 183 Some well-characterized interneurons are covered densely by dendritic spines. 0
Andersen; Hippocampus Book 184 When present, spines on interneurons show profound differences from their counterparts on pyramidal neurons. 1
Andersen; Hippocampus Book 184 The spines of interneurons are covered by numerous excitatory synaptic boutons. 0
Andersen; Hippocampus Book 184 Most pyramidal cell spines have only one bouton occasionally two. 0
Andersen; Hippocampus Book 184 The large number of excitatory spines on interneurons spines raises the possibility that spines of interneurons serve to increase the synaptic surface area and do not function as a compartmentalization device as in pyramidal cells. 0
Andersen; Hippocampus Book 184 Excitatory and Inhibitory Synapses 0
Andersen; Hippocampus Book 184 Within the hippocampal circuit, interneurons receive afferent excitatory input from a number of intrinsic and extrinsic sources. 0
Andersen; Hippocampus Book 184 In addition to their inhibitory inputs onto principal cells, interneurons provide inhibitory input to other interneurons. 0
Andersen; Hippocampus Book 184 In contrast to our appreciation of inhibitory transmission onto principal cells,    much less is known regarding the nature of inhibition between interneuron subpopulations. 0
Andersen; Hippocampus Book 185 In addition to excitatory glutamatergic innervation, many neurons also express muscarinic and nicotinic receptors and receive cholinergic input from the medial septum. 1
Andersen; Hippocampus Book 185 For interneuron inputs, there is evidence for noradrenergic input from the locus coeruleus, serotonergic input from the raphe nucleus, and histaminergic input from the supramammillary nucleus. 0
Andersen; Hippocampus Book 185 Although the roles of many of the neuromodulatory systems are poorly understood, several studies have elucidated the roles of a few of the modulators. 0
Andersen; Hippocampus Book 185 Axonal arborization of local-circuit inhibitory interneurons constitutes another diverse feature of their anatomy. 0
Andersen; Hippocampus Book 185 Each cell type or subclass of inhibitory interneuron innervates distinct subcellular compartments of each of their targets. 0
Andersen; Hippocampus Book 185 The arrangement of axonal distribution predicts the role each interneuron plays in influencing activity of the postsynaptic cell. 0
Andersen; Hippocampus Book 185 Fast-spiking basket cells typically have axons that emerge from either the soma or a proximal dendrite. The axon makes collaterals that extend into the stratum radiatum but primarily arborize throughout the pyramidal cell layer. 0
Andersen; Hippocampus Book 185 Chandelier cells or axo-axonic cells of the dentate gyrus and hippocampus are so named because of the appearance of their axonal arborization. 0
Andersen; Hippocampus Book 203 Synaptic Function 18
Andersen; Hippocampus Book 203 Sherrington coined the term "synapse" (from the Greek "hold together"). 0
Andersen; Hippocampus Book 208 Voltage-Clamp Techniques 5
Andersen; Hippocampus Book 209 The conventional view of synaptic function -- originating from the studies of Katz and coworkers at the neuromuscular junction -- is that transmission is quantized. 1
Andersen; Hippocampus Book 210 Short-term Plasticity 1
Andersen; Hippocampus Book 210 Synapses show numerous forms of memory of their activation history. 0
Andersen; Hippocampus Book 210 The synaptic plasticity of long term potentiation and depression,    LTP and LTD, persist for hours if not longer. 0
Andersen; Hippocampus Book 210 Other forms of use-dependent plasticity last up to a few minutes and may play an important role in the second-to-second traffic of information through synapses. 0
Andersen; Hippocampus Book 210 Increases and decreases in translation -- facilitation, obligation, and potentiation for increases; and depression for decreases. 0
Andersen; Hippocampus Book 211 Facilitation describes the enhancement of transmission frequently seen following a preceding action potential. 1
Andersen; Hippocampus Book 211 Augmentation refers to a gradual increase in synaptic strength with repeated stimulation. 0
Andersen; Hippocampus Book 211 Potentiation requires a high-frequency train of stimuli for its induction and persist for up to a few minutes after the end of the train. 0
Andersen; Hippocampus Book 211 Many synapses do not show potentiation phenomenon and, instead, depress when repeatedly stimulated. 0
Andersen; Hippocampus Book 211 The distinct patterns of short-term plasticity result from a large number of processes occurring principally in the presynaptic terminals. 0
Andersen; Hippocampus Book 211 Postsynaptic mechanisms can also contribute to short-term plasticity. Polarizing synaptic potentials can summate, leading to activation of regenerative currents in postsynaptic dendrite. 0
Andersen; Hippocampus Book 211 Because principal neurons    frequently discharge in bursts of action potentials,    the degree of postsynaptic facilitation or depression during such bursts may contain much of the information transmitted through the network. 0
Andersen; Hippocampus Book 211 It has been argued that lasting changes in short-term plasticity are of greater importance for information encoding than synaptic strength per se. 0
Andersen; Hippocampus Book 211 Because short-term plasticity is mediated predominantly through use-dependent alteration in release probability, the information contained in a facilitating or depressing burst is inevitably corrupted by the stochastic nature of transmitter release. 0
Andersen; Hippocampus Book 211 The main excitatory transmitter in the hippocampus, as elsewhere in the mammalian CNS, is glutamate. 0
Andersen; Hippocampus Book 212 Glutamate-glutamine cycle (diagram) 1
Andersen; Hippocampus Book 213 Most excitatory hippocampus synapses are mediated by AMPA and NMDA receptors, which have strikingly different biophysical and pharmacological properties. 1
Andersen; Hippocampus Book 213 AMPA receptors require a rapid pulse of glutamate in excess of approximately 100 µmol to open. 0
Andersen; Hippocampus Book 213 AMPA receptors show a rapid rise time (100-600 µs at physiological temperature). This reflects both very fast binding kinetics and a high opening probability. 0
Andersen; Hippocampus Book 213 AMPA receptors deactivate rapidly following clearance of synaptic glutamate (with a time constant of 2.3-3.0 ms). 0
Andersen; Hippocampus Book 215 NMDA receptors show many striking properties that mark them out as quite different from AMPA and kainate receptors. 2
Andersen; Hippocampus Book 215 NMDA receptors have very slow kinetics    and can continue to mediate an ion flux for several hundreds of milliseconds after the glutamate pulse has terminated    (activation time constant is approximately 7 ms;    deactivation time constants are approximately 200 ms and 1-3 seconds). 0
Andersen; Hippocampus Book 216 Metabotropic receptors contain seven transmembrane segments and are coupled to nucleotide-binding G proteins, which mediate most of their actions. 1
Andersen; Hippocampus Book 218 GABA receptors are divided into ionotropic (GABAA) and metabotropic (GABAB) receptors. 2
Andersen; Hippocampus Book 219 GABA cycle. The inhibitory neurotransmitter GABA is synthesized from glutamate via the action of two enzymes. (diagram) 1
Andersen; Hippocampus Book 220 In comparison with glutamate and GABA,    other neurotransmitters are present at far fewer synapses. 1
Andersen; Hippocampus Book 221 Among other small molecules that act as neurotransmitters are the monoamines    noradrenaline (norepinephrine),    dopamine (DA),    serotonin (5-HT),    and histamine. 1
Andersen; Hippocampus Book 221 The hippocampus receives dopaminergic projections from both the substantia nigra and the ventral tegmental area. 0
Andersen; Hippocampus Book 221 It is possible that the main role of dopamine is to modulate synaptic transmission. 0
Andersen; Hippocampus Book 222 A large number of peptides have also been shown to exist in axonal varicosities and to bind to specific receptors in the hippocampus. 1
Andersen; Hippocampus Book 222 Hippocampal synapses usually occur at hippocampal varicosities (the widely used term "terminal" is thus misleading). 0
Andersen; Hippocampus Book 222 Varicosities occur at irregular intervals along many axons. 0
Andersen; Hippocampus Book 223 The most abundant type of synapse in the hippocampus is the small glutamatergic synapse made on dendritic spines. 1
Andersen; Hippocampus Book 225 The average release probability at Schaffer collateral-CA1 pyramidal neuron synapses is probably less than 50%, although it is highly variable from synapse to synapse. 2
Andersen; Hippocampus Book 225 Even though a pyramidal neuron has 10,000 to 30,000 spine synapses, it has been estimated that only 16 to 26 need to fire synchronously to bring it to action potential threshold. 0
Andersen; Hippocampus Book 225 Because the dendrites of CA1 pyramidal neurons can extend up to 500 µ from the soma,    an important question is whether distal synapses are as effective as proximal ones. 0
Andersen; Hippocampus Book 225 Dentate granule cells are much smaller and have fewer total spines than pyramidal neurons, although they have the same spine density per unit length of dendrite. 0
Andersen; Hippocampus Book 226 Mossy fibers are the fan unmyelinated axons of dentate granule cells. 1
Andersen; Hippocampus Book 229 GABAergic inhibition of principal neurons plays an essential role in regulating the transmission of information through the hippocampal formation. 3
Andersen; Hippocampus Book 230 Most GABAergic synapses show marked depression with repetitive activity at moderate frequencies. 1
Andersen; Hippocampus Book 243 Molecular Mechanisms of Synaptic Function in the Hippocampus 13
Andersen; Hippocampus Book 243 In the hippocampus, excitatory (also termed principle or pyramidal) neurons, the basic working units of the mammalian central nervous system (CNS), form a highly organized three-layer circuit. 0
Andersen; Hippocampus Book 244 Synaptic vesicles are kept in two spatially and functionally distinct pools: the reserve pool and the readily releasable pool. 1
Andersen; Hippocampus Book 244 Synaptic vesicles, after their mobilization toward the active zone, undergo a number of trafficking steps before achieving a state in which they are ready to fuse with the presynaptic plasma membrane, the so call readily releasable state. 0
Andersen; Hippocampus Book 297 Local Circuits 53
Andersen; Hippocampus Book 297 Local circuits play a critical role in determining the pattern of output from discrete brain regions receiving multiple inputs over time. 0
Andersen; Hippocampus Book 297 Individual neurons act as integrators of multiple app for inputs and/or coincidence detectors. 0
Andersen; Hippocampus Book 297 Hippocampal neurons are divided into two major classes:    principal cells and interneurons. 0
Andersen; Hippocampus Book 297 Interneurons are considerably less abundant (less than 10%) than spiny principal neurons such as granule and mossy cells and it didn't take gyrus and Brett pyramidal neurons in the CA1 and CA3 areas. 0
Andersen; Hippocampus Book 297 Despite their relatively small numbers, there is an astonishing variety of interneuron classes. 0
Andersen; Hippocampus Book 297 In addition to highlighting the diversity of interneuronal subtypes, research data has revealed an equally bewildering complexity of interneuronal organization. 0
Andersen; Hippocampus Book 297 Certain classes of hippocampal interneurons establish a commissural axon collateral or even project to extrahippocampal targets. 0
Andersen; Hippocampus Book 297 Virtually all excitatory hippocampal projection neurons have a local axonal arbor and could be considered local-circuit neurons. 0
Andersen; Hippocampus Book 297 Hippocampal interneurons can be defined operationally as GABAergic non-principal cells. 0
Andersen; Hippocampus Book 298 Input Specificity of Extrinsic Afferents 1
Andersen; Hippocampus Book 298 All hippocampal subfields received an abundance of extrinsic afferents, which can be grouped into three broad classes: (1) glutamatergic inputs, (2) septo-hippocampal GABAergic projection, (3) several pathways from brain stem and forebrain nuclei. 0
Andersen; Hippocampus Book 298 Glutamatergic inputs (e.g., originating in entorhinal cortex and other ipsilateral and contralateral hippocampal subregions. 0
Andersen; Hippocampus Book 298 Brain stem and four brain nuclei releasing neurotransmitters that act as neuromodulators, among them acetylcholine, dopamine, serotonin, and noradrenaline (norepinephrine). 0
Andersen; Hippocampus Book 298 Excitatory, glutamatergic afferent pathways show a high degree of lamina selectivity. 0
Andersen; Hippocampus Book 298 The lamina specificity of inputs can have powerful effects on shaping output from the target population. 0
Andersen; Hippocampus Book 298 Hippocampal principal cells show a marked distribution pattern of intrinsic conductance. 0
Andersen; Hippocampus Book 298 Conduct and set favors for semantic responses is preferentially located on this till dendritic compartments. 0
Andersen; Hippocampus Book 298 The distribution of conductance has profound effects on integrative and coincidence-detection abilities. 0
Andersen; Hippocampus Book 298 The high degree of the laminar specificity of glutamatergic input to hippocampal subregions is also accompanied by specificity in interneuron targets. 0
Andersen; Hippocampus Book 298 The architecture provides specific target region responses to specific inputs at both the cellular compartment level and local circuit levels. 0
Andersen; Hippocampus Book 298 Cholinergic axons branched profusely and all hippocampal layers and establish synaptic contacts with both principal cells and interneurons. 0
Andersen; Hippocampus Book 298 Noradrenergic afferents from the locus coeruleus do not appear to have a particular target preference but I particularly dance in areas that receive mossy fiber input. 0
Andersen; Hippocampus Book 298 Serotoninergic-hippocampal projection also shows a lack of specificity. 0
Andersen; Hippocampus Book 298 Although most hippocampal neurons express dopamine receptors,    mesohippocampal projections are predominately to area CA1. 0
Andersen; Hippocampus Book 298 Noradrenergic fibers from the locus coeruleus project mainly to the dentate gyrus. 0
Andersen; Hippocampus Book 299 Patterns of Local Circuit Connectivity 1
Andersen; Hippocampus Book 299 Feedforward inhibition serves to impose a temporal framework on a target area on the basis of inputs received. 0
Andersen; Hippocampus Book 299 The delay associated with an additional synapse ensures that a feedforward inhibitory synaptic pulse does not impinge on the initial, direct extrinsic synaptic event in principal neurons. 0
Andersen; Hippocampus Book 299 Some anti-neurons receive and put only from extrinsic afferents and can thus possess a paid only in feedforward inhibition. 0
Andersen; Hippocampus Book 299 Feedforward inhibition can account for most of the input from extrinsic sources. 0
Andersen; Hippocampus Book 299 Mossy fiber axons in the area CA3 make roughly 10 times as many contacts with CA3 interneurons as with the far more numerous CA3 principal cells. 0
Andersen; Hippocampus Book 299 When principal neurons fire,    a number of interneurons    receives synaptic excitation. 0
Andersen; Hippocampus Book 299 Interneurons target local principal cells,    thus providing a feedback inhibitory circuit. 0
Andersen; Hippocampus Book 299 Local feedback circuits can account for most of the local output    from principal neurons. 0
Andersen; Hippocampus Book 299 In area CA1,    excitatory neurons have a strong preference for interneurons as targets. 0
Andersen; Hippocampus Book 299 Generation of the output action potential from a hippocampal subregion is followed rapidly by period of marked local inhibition. 0
Andersen; Hippocampus Book 299 Many interneurons can be involved in both feedforward and feedback inhibition, providing a functional link between afferent input patterns in any resulting output from the target area. 0
Andersen; Hippocampus Book 299 Recurrent connections are not limited to interneurons. 0
Andersen; Hippocampus Book 299 Recurrent excitation is also seen in a hippocampal local circuits. 0
Andersen; Hippocampus Book 299 In the hippocampus, they are probably few, if any, neurons without local axon collaterals synapse thing own neighboring neurons. 0
Andersen; Hippocampus Book 299 In general, principal neurons were he currently excited other local (or neighboring) principal neurons as well as interneurons. 0
Andersen; Hippocampus Book 300 Basic Local Circuit Interactions (diagram) 1
Andersen; Hippocampus Book 301 Dentate Gyrus 1
Andersen; Hippocampus Book 301 Granule cells are the principal neuronal type of the dentate gyrus. 0
Andersen; Hippocampus Book 301 The sole afferent projection of granule cells of the dentate gyrus is that mossy fiber pathway, forming the second link of the tri-synaptic loop targeting the CA3 pyramidal cells. 0
Andersen; Hippocampus Book 301 Within the dentate gyrus, granule cells may function as elements in circuits generating feedforward and feedback inhibition as well as recurrent excitatory circuits. 0
Andersen; Hippocampus Book 302 Basic organization of interneuron output fields in the dentate gyrus (diagram) 1
Andersen; Hippocampus Book 305 Area CA3 and CA1 3
Andersen; Hippocampus Book 305 In the classic hippocampal tri-synaptic circuit, activity is projected from the dentate gyrus to CA3 and then from CA3 via Schaffer collaterals to CA1. 0
Andersen; Hippocampus Book 305 Direct input to area CA3 and CA1 also originate from the entorhinal cortex. 0
Andersen; Hippocampus Book 305 The principal neurons in the hippocampal subfields constitute a relatively homogeneous population of glutamate-releasing pyramid-shaped neurons. 0
Andersen; Hippocampus Book 305 In the CA1 and CA3 areas pyramidal neurons bear numerous spines, with estimates being as high as 30,000. 0
Andersen; Hippocampus Book 305 Most of these spines receive a single excitatory synapse. 0
Andersen; Hippocampus Book 305 Although all pyramidal neurons have a local axonal arbor, most excitatory synapses in the hippocampal subfields are of extraneous origin, arriving from a multitude of sources. 0
Andersen; Hippocampus Book 306 The excitatory synapse sources for pyramidal neurons include -- a different hippocampal subfield, the contralateral hippocampus, the entorhinal cortex, the submammillary body, and thalamic nuclei. 1
Andersen; Hippocampus Book 321 Structural Plasticity 15
Andersen; Hippocampus Book 321 The hippocampus formation has been described as a relatively late-developing brain region. 0
Andersen; Hippocampus Book 321 The hippocampus appears to undergo dynamic modifications continually    in the form of dendritic extension and retraction    as well as synaptic formation and elimination. 0
Andersen; Hippocampus Book 321 Perhaps the most basic of all structural changes is the addition of new neurons, a phenomenon known as neurogenesis. 0
Andersen; Hippocampus Book 321 Neurogenesis is now recognized to be a substantial process in some regions of the adult brain. 0
Andersen; Hippocampus Book 321 They didn't take gyrus of the rat adds thousands of new neurons every day throughout adulthood. 0
Andersen; Hippocampus Book 321 The incorporation of new neurons into pre-existing second straight results in a cascade of structural changes that further rate increase the structural plasticity of the region. 0
Andersen; Hippocampus Book 321 New neurons elaborate axons and dendrites and undergo synaptogenesis. 0
Andersen; Hippocampus Book 321 Progressive events of neurodegenerative in hippocampus are typically followed by a series and regressive phenomena, such as cell death, which likely involves process retraction and synapse of elimination. 0
Andersen; Hippocampus Book 321 New neurons are formed in the dentate gyrus    throughout life. 0
Andersen; Hippocampus Book 321 Modulation of neurogenesis in the dentate gyrus by hormones and by experience. 0
Andersen; Hippocampus Book 321 Dendritic and Synaptic Plasticity and a Hippocampal Formation 0
Andersen; Hippocampus Book 321 Hippocampus is a region with a large degree of structural plasticity. 0
Andersen; Hippocampus Book 321 Define structure, and sometimes even the gross structure of the hippocampal formation is constantly changing under normal conditions. 0
Andersen; Hippocampus Book 321 The hippocampal formation is a dynamic area whose synapses and dendrites are undergoing continuous rearrangement. 0
Andersen; Hippocampus Book 322 Hormones and Dendritic Architecture 1
Andersen; Hippocampus Book 322 High levels of circulating glucocorticoids have been associated with atrophy of dendrites in the CA3 region. 0
Andersen; Hippocampus Book 322 Dendritic architecture and the hippocampus is influenced by experience. 0
Andersen; Hippocampus Book 322 Chronic stress has generally been shown to have negative effects on the structure of dendrites in the hippocampus. 0
Andersen; Hippocampus Book 322 Environmental Complexity and Learning 0
Andersen; Hippocampus Book 322 Living in enriched environments increases the size of the dendritic tree, the number of dendritic spines, and the number of synapses in the hippocampus. 0
Andersen; Hippocampus Book 323 Structural changes in the hippocampus as a result of learning, or long term potentiation (LTP), a form of synaptic plasticity associated with learning. 1
Andersen; Hippocampus Book 323 The hippocampal formation has a remarkable capacity for regeneration after injury. 0
Andersen; Hippocampus Book 323 Animal models of disease states such as epilepsy and stroke. 0
Andersen; Hippocampus Book 323 With time following seizure or stroke, there is considerable structural reorganization in the form of axon sprouting, which could be viewed as regenerative. 0
Andersen; Hippocampus Book 323 The brain is protected from mechanical injury by the skull and from chemical injury by the blood-brain barrier. 0
Andersen; Hippocampus Book 323 It is not obvious that the regenerative capacity inherent in the hippocampus evolved to correct brain damage, particularly that which occurs in old age. 0
Andersen; Hippocampus Book 324 Transplantation of neural stem cells into damaged hippocampus has shown that new neurons can arise from progenitors, migrate to their appropriate locations where the former long-distance axons, make appropriate connections, and exhibit normal electrophysiological responses. 1
Andersen; Hippocampus Book 324 Studies suggest that the hippocampus, particularly of the dentate gyrus, is conducive to the acceptance of neural stem cell transplants. 0
Andersen; Hippocampus Book 324 Conditions such as Alzheimer's disease, which result in the accumulation of abnormal proteins and the formation of senile plaques and neurofibrillary tangles, may be less amenable to transplantation. 0
Andersen; Hippocampus Book 324 Although Neurogenesis 0
Andersen; Hippocampus Book 324 The dentate gyrus is one of two brain regions (other is olfactory bulb) in which adult neurogenesis has been widely recognized. 0
Andersen; Hippocampus Book 324 Adult neurogenesis has been observed in the hippocampus in virtually every mammalian species examined. 0
Andersen; Hippocampus Book 325 Adult neurogenesis was rediscovered in the dentate gyrus and olfactory bulb during the 1990s and is now a relatively well-established phenomenon. 1
Andersen; Hippocampus Book 326 Hormones and Adult Neurogenesis 1
Andersen; Hippocampus Book 326 The hippocampus formation is known to be richly endowed with hormone receptors. 0
Andersen; Hippocampus Book 326 Many cell types in the hippocampal formation contain hormone receptors and respond to experimental hormone manipulations during adulthood with dramatic structural changes. 0
Andersen; Hippocampus Book 326 Studies have shown that the production of new neurons in the dentate gyrus is sensitive to the levels of circulating steroid hormones. 0
Andersen; Hippocampus Book 326 Glucocorticoids inhibit the production of new neurons by decreasing the proliferation of granule cell precursors. 0
Andersen; Hippocampus Book 328 Experienced and Adult Neurogenesis 2
Andersen; Hippocampus Book 328 Environmental experience takes many forms: sensory and motor experience, changing cognitive demands, and stress. 0
Andersen; Hippocampus Book 328 A major component of the "fight or flight" reaction is the mobilization of energy stores to facilitate reaction to the imminent danger. 0
Andersen; Hippocampus Book 328 Stress inhibits the production of new granule cells during development and in adulthood. 0
Andersen; Hippocampus Book 330 Physical activity increases cell pole for ration and ultimately the production of new neurons in the dentate gyrus of adult rodents. 2
Andersen; Hippocampus Book 330 Individual Differences in Adult Neurogenesis 0
Andersen; Hippocampus Book 330 When adult rodents are group housed in a relatively large, complex and closure, a dominance hierarchy forms. 0
Andersen; Hippocampus Book 330 Dominant animals, characterized by the amount of offenses or aggressive behavior displayed, have substantially more new neurons than subordinate animals. 0
Andersen; Hippocampus Book 331 Subordinate chickadees make fewer new cells in the hippocampus than dominant chickadees. 1
Andersen; Hippocampus Book 331 Neurogenesis Following Damage 0
Andersen; Hippocampus Book 331 Neurogenesis is upregulated in neurodegenerative conditions such as Alzheimer's disease and Parkinson's disease. 0
Andersen; Hippocampus Book 332 Not only are there well known differences between different cell types, there are also developmental differences between individual cells of the common cell type. 1
Andersen; Hippocampus Book 332 The granule cell layer consists of neurons ranging in age from hours to years. 0
Andersen; Hippocampus Book 332 Although many thousands of new neurons are added to the dentate gyrus every day, this is a relatively small proportion of the large number of material granule neurons produced during development and that survive through to adulthood. 0
Andersen; Hippocampus Book 332 Adult generated neurons are likely to have structural characteristics that differ from developmentally generated neurons. 0
Andersen; Hippocampus Book 332 Adult-generated granule cells are capable of undergoing rapid structural change, as evidenced by the fact that they have axons in the distal CA3 within 4 to 10 days at the mitosis. 0
Andersen; Hippocampus Book 332 Much work is needed to determine the functional characteristics of new neurons in the dentate gyrus. 0
Andersen; Hippocampus Book 332 The daily production of thousands of new granule cells and their incorporation into the existing circuitry are costly in terms of energy expenditure. 0
Andersen; Hippocampus Book 332 The continual influx of new cells provide some aspect of function of the dentate gyrus that cannot be obtained with a structure comprising mature neurons exclusively. 0
Andersen; Hippocampus Book 332 The existence of a large pool of immature neurons in a brain region raises the possibility that these new cells are important for certain types of learning and memory. 0
Andersen; Hippocampus Book 332 A widely held view is that the hippocampus formation plays a temporary role in storing new memories. 0
Andersen; Hippocampus Book 332 Recent, but not remote, memories for certain information are eliminated by lesioning the hippocampal formation. 0
Andersen; Hippocampus Book 332 Neurons produced during adulthood might play a role in memory processing for a short time after their generation. 0
Andersen; Hippocampus Book 333 New cells might degenerate or undergo changes in connectivity, gene expression, or both around the time the hippocampal formation no longer plays a role in the storage of that particular memory. 1
Andersen; Hippocampus Book 333 A temporary role for adult-generated granule neurons in learning has been suggested in canaries. 0
Andersen; Hippocampus Book 333 Neural network models of memory formation support a distributed perspective of memory storage. 0
Andersen; Hippocampus Book 333 Examples of factors that enhance both the number of new neurons and hippocampus-dependent learning are estrogen treatment and living in an enriched environment. 0
Andersen; Hippocampus Book 333 Situations that decrease the number of new hippocampus neurons, such as glucocorticoids and stress, are associated with impaired performance. 0
Andersen; Hippocampus Book 333 Aging is associated with a decline in new cell production in the hippocampus. 0
Andersen; Hippocampus Book 333 Chronic stress has been shown to inhibit neurogenesis persistently. 0
Andersen; Hippocampus Book 333 Other age-associated changes dominate hippocampal function, such as diminished number of synapses. 0
Andersen; Hippocampus Book 333 New cells are likely to require some time for integration into the existing circuitry. 0
Andersen; Hippocampus Book 333 Dendrites must be grown    and functional synaptic connections formed;    axons must grow   and find their targets. 0
Andersen; Hippocampus Book 333 Chronic changes in cell proliferation are those most likely to have functional consequences. 0
Andersen; Hippocampus Book 333 Acute stress and chronic stress diminished the proliferation of granule cell precursors in the dentate gyrus. 0
Andersen; Hippocampus Book 333 Acute stress has been shown (with certain paradigms) to enhance learning,    whereas chronic stress typically impairs learning. 0
Andersen; Hippocampus Book 333 A direct link between new neurons and learning remains controversial. 0
Andersen; Hippocampus Book 333 A research study has shown that approximately 9000 new cells are produced every day in the rat dentate gyrus. 0
Andersen; Hippocampus Book 333 If the granule cells produced during adulthood are functionally different -- less likely to be inhibited by GABA and more likely to display synaptic plasticity -- they could be especially influential. 0
Andersen; Hippocampus Book 333 Despite the fact that involved mother of new neurons and learning is plausible, the available evidence supporting this view is incomplete and mixed. 0
Andersen; Hippocampus Book 334 Behavioral changes following lesions of the hippocampus rarely uncover a learning impairment unless a large percentage of the total hippocampal formation is destroyed. 1
Andersen; Hippocampus Book 334 The hippocampal formation has been linked functionally to regulation of the HPA (hypothalamic-pituitary-adrenal) axis. 0
Andersen; Hippocampus Book 334 The hippocampus formation is purported to play a role in limiting the level of circulating glucocorticoids following stress 0
Andersen; Hippocampus Book 334 Prenatal and postnatal stress have been shown to result in persistent changes in the HPA axis in the form of inefficient shutoff of the stress response during adulthood. 0
Andersen; Hippocampus Book 335 Antidepressants enhance hippocampal neurogenesis. 1
Andersen; Hippocampus Book 343 Synaptic Plasticity in the Hippocampus 8
Andersen; Hippocampus Book 343 Of all the properties of hippocampal synapses, perhaps the most beguiling inconsequential, and certainly the most enthusiastically studied, is their ability to respond to specific patterns of activation with long-lasting increases or decreases in synaptic efficacy. 0
Andersen; Hippocampus Book 343 Synaptic plasticity is a property of many, perhaps most, excitatory synapses in the brain. 0
Andersen; Hippocampus Book 343 During the period from 1966 to mid-1980s, the major characteristics of LTP, including its persistence, and specificity, and associativity, were established,    the critical role of the NMDA receptor in the induction of LTP identified,    and the first steps taken to link LTP to hippocampus dependent learning. 0
Andersen; Hippocampus Book 343 The cellular event that triggers the induction of LTP is the influx of calcium to the activating NMDA receptor. 0
Andersen; Hippocampus Book 343 The various short-term forms of plasticity that hippocampus synapses share with most if not all synapses: paired pulse facilitation and depression and post tetenic potentiation. 0
Andersen; Hippocampus Book 343 The mossy fiber projection from the granule cells to CA3 pyramidal cells supports a very different form of LTP. 0
Andersen; Hippocampus Book 344 The term "synaptic plasticity" was introduced by the Polish psychologist Jerry Konorski to describe the persistent, activity driven changes in synaptic efficacy that he assumed to be the basis of information storage in the brain.    (Konorski, 1948). 1
Andersen; Hippocampus Book 344 A formal hypothesis embodying the idea of synaptic plasticity was advanced by the Canadian psychologist Donald Hebb in 1949. 0
Andersen; Hippocampus Book 344 In 1973,    long-lasting changes in synaptic efficacy at perforant path granule cell synapses in the hippocampus could be induced by a brief titanic stimulation    (Bliss and Lomo, 1973). 0
Andersen; Hippocampus Book 344 The discovery of what has come to be known as long term potentiation (LTP) emerged from experiments that Per Andersen and Lomo, then a PhD student, were conducting at the University of Oslo during the mid-1960s on the phenomenon of frequency potentiation in excitatory hippocampal pathways. 0
Andersen; Hippocampus Book 346 LTP was revealed that two other hippocampal pathways: the mossy fiber projection to CA3 pyramidal cells and the interleaved commissural and Schaffer collateral fibers from CA3 to CA1 pyramidal cells. We refer to these fibers as the Schaffer-commissural projection. 2
Andersen; Hippocampus Book 346 The hypothesis that  NMDA receptor activation is required for inducing LTP received further support in 1986. 0
Andersen; Hippocampus Book 347 During the mid-1980s, LTP gained acceptance as a physiological mechanism underlying the cognitive faculties of learning and memory. 1
Andersen; Hippocampus Book 347 Synaptic transmission at the level of the single synapse is an inherently stochastic process that can be modulated by prior activity in the presynaptic or postsynaptic neuron and by a wide variety of neuromodulators acting both pre- and post-synaptically. 0
Andersen; Hippocampus Book 352 A wide range of stimulus protocols can induce LTP. 5
Andersen; Hippocampus Book 353 Time course of LTP -- Rapid Onset and Variable Duration 1
Andersen; Hippocampus Book 353 Three distinct temporal components potentiation -- STP, Early LTP, Late LTP 0
Andersen; Hippocampus Book 353 A component of LTP, usually lasting less than an hour, referred to a short-term potentiation (SDP). 0
Andersen; Hippocampus Book 353 STP is NMDA receptor-dependent but depends neither on protein synthesis nor on protein kinase activity. 0
Andersen; Hippocampus Book 355 Associativity -- Induction of LTP Is Influenced by Activity at Other Synapses 2
Andersen; Hippocampus Book 356 The requirement for tight coincidence that presynaptic and postsynaptic activity implies a Hebbian induction rule. 1
Andersen; Hippocampus Book 356 There is convincing evidence that the induction of LTP in the Schaffer-commissural projection in area CA1 is indeed Hebbian in nature. 0
Andersen; Hippocampus Book 357 The most remarkable advance in understanding the cellular mechanisms of LTP has been elucidation of the role of the NMDA receptor in its induction. 1
Andersen; Hippocampus Book 358 Explicit and Hebb's postulate is the notion of causality. In a Hebb synapse, an increase in synaptic weight occurs only when the presynaptic cell fire shortly before the postsynaptic cell. 1
Andersen; Hippocampus Book 359 Ca2+ signaling in LTP 1
Andersen; Hippocampus Book 359 Ca2+ release from Ca2+ stores contributes to induction of LTP. 0
Andersen; Hippocampus Book 359 A major source of Ca2+ in neurons is via release from intracellular stores. 0
Andersen; Hippocampus Book 359 It is accepted that Ca2+ entry directly through the NMDAR channel is a trigger for NMDAR-dependent LTP. 0
Andersen; Hippocampus Book 373 Studies of kinases in NMDA receptor-dependent LTP have shown that several kinases are involved but none is obligatory. 14
Andersen; Hippocampus Book 377 Modification of the Existing Receptors Contributes to LTP 4
Andersen; Hippocampus Book 379 Insertion of AMPA receptors contributes to  LTP. 2
Andersen; Hippocampus Book 383 Retrograde signaling is required for communication between the postsynaptic site of induction and the presynaptic terminal. 4
Andersen; Hippocampus Book 384 Membrane spanning molecules contribute to signaling between presynaptic and postsynaptic sides of the synapse. 1
Andersen; Hippocampus Book 385 Cell adhesion molecules (CAM's) comprise a large class of diverse membrane-spanning molecules with extracellular ligand-binding domains that are important for cell recognition during neural development. 1
Andersen; Hippocampus Book 385 Cadherins are an extensive family of cell adhesion molecules with cytoplasmic signaling domains that are linked to the actin cytoskeleton through two accessory proteins. 0
Andersen; Hippocampus Book 388 Transcription and translation of new mRNAs -- dialogue between Synapse and Nucleus 3
Andersen; Hippocampus Book 388 Protein synthesis at both the local and global levels is involved in the conversion of the early to late LTP. 0
Andersen; Hippocampus Book 388 A major route for activity-dependent protein synthesis proceeds via long-range activation of nuclear transcription factors, including members of the CREB family of proteins, which bind to cAMP response elements (CREs) in the regulatory regions of target genes to initiate transcription. 0
Andersen; Hippocampus Book 388 The MAP kinase signaling cascade can be triggered by a wide variety of stimuli, including extracellular ligands binding to receptor tyrosine kinases and G. protein coupled receptors, and by synaptic activity leading to calcium entry through the ionotropic glutamate receptors or voltage-gated calcium channels. 0
Andersen; Hippocampus Book 389 Stimulation of dopamine receptors can induce late potentiation in an activity independent manner. 1
Andersen; Hippocampus Book 389 Dopamine receptor activation leads to the upregulation of cAMP and presumptive translocation of activated PKA to the soma, where it can directly phosphorylate CREB on ser133. 0
Andersen; Hippocampus Book 389 The nuclear transcription factor CREB is a target for several kinases. 0
Andersen; Hippocampus Book 392 Signaling pathways involved in the genesis of late LTP (diagram) 3
Andersen; Hippocampus Book 393 The duration of a late LTP is regulated by the NMDA receptor. 1
Andersen; Hippocampus Book 393 The expression of a late LTP depends on de novo protein synthesis around the time of induction, give or take a few hours. 0
Andersen; Hippocampus Book 393 Structural remodeling and growth of spines can be stimulated by induction of LTP. 0
Andersen; Hippocampus Book 397 Alterations in the cytoskeleton contribute to the LTP and LTD. 4
Andersen; Hippocampus Book 397 Dendritic spines are not static structures; rather, their shape is determined from moment to moment    by the dynamics of the actin cytoskeleton. 0
Andersen; Hippocampus Book 398 LTP at Mossy Fiber Synapses 1
Andersen; Hippocampus Book 398 LTP takes a very different form at the largest synapses in the hippocampus,    indeed among the largest in the mammalian brain --    the synapses made by granule cell axons (the mossy fibers) on CA3 pyramidal cells. 0
Andersen; Hippocampus Book 403 Despite its independence of the NMDA receptor, it is evident that the LTP at mossy fiber synapses requires an increase in intracellular Ca2+; but whether the critical compartment is a presynaptic terminal or the postsynaptic spine remains unresolved and may depend on the pattern of the plasticity-inducing stimulation. 5
Andersen; Hippocampus Book 403 Increase in Ca2+ is not achieved by activation of NMDA receptors. Instead, increases in Ca2+ are achieved by a variety of alternative routes. 0
Andersen; Hippocampus Book 403 The long (1 second) trains at 100 Hz that are required to produce robust mossy fiber LTP are not likely to be mimicked by granule cells in vivo. 0
Andersen; Hippocampus Book 403 It remains to be established whether naturally occurring patterns of granule cell activity lead to LTP at mossy fiber synapses. 0
Andersen; Hippocampus Book 475 Hippocampal Physiology in the Behaving Animal 72
Andersen; Hippocampus Book 549 Functional Role of the Human Hippocampus 74
Andersen; Hippocampus Book 549 The hippocampus is part of a system that plays a critical role in the encoding and retrieval of long-term memory for facts and events. 0
Andersen; Hippocampus Book 549 The hippocampus is vital for "declarative" or "explicit" form of memory but is not involved in other forms of long-term memory, in non-mnemonic aspects of cognition, or in immediate (or "working") memory. 0
Andersen; Hippocampus Book 549 Hippocampus involvement in declarative memory is not permanent but is time-limited. 0
Andersen; Hippocampus Book 549 The hippocampal region "combines and extends" the processing of adjacent cortical structures that together form the medial temporal lobe memory system. 0
Andersen; Hippocampus Book 550 Patient HM 1
Andersen; Hippocampus Book 562 The term "priming" refers to a class of implicit memory tasks that are not affected by medial temporal lobe damage 12
Andersen; Hippocampus Book 563 A second form of priming, known as conceptual priming, is apparently intact in amnesia. 1
Andersen; Hippocampus Book 564 Dissociation between declarative memory tasks that involve the hippocampus and nondeclarative memory tasks that do not. 1
Andersen; Hippocampus Book 565 H.M.'s remote memory appeared to be intact in face of both his profound and impaired ability to learn new information and a profound loss of information that he had been exposed to for some time prior to his operation. 1
Andersen; Hippocampus Book 565 Some form of consolidation occurs by which memories that initially rely on structures in the medial temporal lobe become independent of the medial temporal lobe over time. 0
Andersen; Hippocampus Book 569 Associations, Recollections, Episodes, or Sources 4
Andersen; Hippocampus Book 569 A large amount of research of the human hippocampus has been named at functionally dissociating the role of the hippocampus from the role of adjacent cortical structures. 0
Andersen; Hippocampus Book 581 Theories of Hippocampal Function 12
Andersen; Hippocampus Book 581 How memory handles ambiguity, associated-relations, and context. 0
Andersen; Hippocampus Book 582 Contacts, relations, and configurations may each help disambiguate conflicting associative relations in which a specific stimulus occurs. 1
Andersen; Hippocampus Book 582 The hippocampus has been implicated in a range of brain functions including acting as a comparator to detect novelty. 0
Andersen; Hippocampus Book 582 Marr's proposal that distributed associative memory could be implemented by hippocampus of close circuitry. 0
Andersen; Hippocampus Book 582 Neural network modeling has matured to a level of conceptual and mathematical precision. (Rolls and Treves, 1998) 0
Andersen; Hippocampus Book 582 Neural activity in the hippocampal formation contributes to episodic memory. 0
Andersen; Hippocampus Book 582 Episodic memory has been variously characterized as remembering the "scenes" in which events take place. 0
Andersen; Hippocampus Book 589 Genomic Sequence Similarity in Mammals (diagram) 7
Andersen; Hippocampus Book 591 Declarative Memory Theory 2
Andersen; Hippocampus Book 591 (1) the primary function of the hippocampal formation is in memory. 0
Andersen; Hippocampus Book 591 (2) the role of the hippocampal formation and memory is selective. It mediates the memory of facts and events, call Declarative Memory. 0
Andersen; Hippocampus Book 591 (3) the hippocampal formation is one of a number of structures that comprise a medial temporal lobe memory system. 0
Andersen; Hippocampus Book 591 (4) time-limited: the role of the hippocampus in memory is time-limited. The hippocampus contributes to a time-dependent systems-level consolidation process such that, once completed, long-term memory traces are stored in the cortex and neural activity in the hippocampus is no longer required for or involved in the recall. 0
Andersen; Hippocampus Book 592 Taxonomy of mammalian memory systems. The scheme was first introduced my Squire (1987) and has been updated many times since. (diagram) 1
Andersen; Hippocampus Book 594 Medial temporal lobe memory system. Major component of Squire's of medial temporal lobe memory system. (diagram) 2
Andersen; Hippocampus Book 595 System-level memory consolidation. Pathways between neocortical areas representing recent events or recently acquired facts. (diagram) 1
Andersen; Hippocampus Book 606 Remote Memory, Retrograde Amnesia, and the Time Course of Memory Consolidation in Primates 11
Andersen; Hippocampus Book 616 Are Fact Memory and Event Memory Processed by a Common Brain System? 10
Andersen; Hippocampus Book 616 Amnesia patients have a deficit restricted to the episodic memory. They cannot remember events so any length of time, but they're factual knowledge about their world and in knowledge of language are both intact. Semantic memory shows all the appearances of being preserved. 0
Andersen; Hippocampus Book 616 The reason amnesia patients display in tax semantic memory is because so much of a person's factual knowledge was acquired years earlier, extending from the years of childhood on through life. Consolidation of such memory traces would be long completed. 0
Andersen; Hippocampus Book 616 An amnesic patient's failure of event memory often relates to relatively recent events such as a forgotten conversation of the day before. 0
Andersen; Hippocampus Book 616 Most amnesic patients have some residual episodic memory function. 0
Andersen; Hippocampus Book 617 Amnesia is largely exclusive to episodic memory. 1
Andersen; Hippocampus Book 617 Amnesiacs are temporally and spatially disoriented: forgetting the date and appointments, getting lost, mislaying their belongings. 0
Andersen; Hippocampus Book 617 Success in recalling either a fact or an event depends only on the "strength" of the traces established through consolidation. 0
Andersen; Hippocampus Book 617 It has been argued that memory for an event requires access to a hippocampally-based "contextual" trace (where the event happened) and a prefrontal temporal trace (when the event happened). 0
Andersen; Hippocampus Book 617 Retrieval of event memory is a reconstruction based on both the "where" trace and the "when" trace, and other information about the event itself, stored elsewhere in the neocortex. 0
Andersen; Hippocampus Book 617 We still do not understand the precise role of the hippocampus in episodic and semantic memory. 0
Andersen; Hippocampus Book 617 Hippocampus and Space: Cognitive Map Theory of Hippocampus Function 0
Andersen; Hippocampus Book 617 "Place cells" in the hippocampus of freely moving rats. 0
Andersen; Hippocampus Book 618 "Cognitive mapping" dates back to Tolman's classic paper (Tolman, 1948). 1
Andersen; Hippocampus Book 618 Cognitive Map Theory 0
Andersen; Hippocampus Book 618 (1) Representation: the vertebrate brain has a neural system that organizes the encoding and representation of perceive stimuli with respect to an allocentric spatial framework, or cognitive map. The spatial locations of the landmarks are stored in this map during exploration. This locale system is in the hippocampus. 0
Andersen; Hippocampus Book 618 (2) Navigation: they locale system is used for spatial navigation. 0
Andersen; Hippocampus Book 618 (3) Evolution and the laws of learning: spatial mapping evolve as one of the multiple memory systems of the vertebrate brain with its own distinctive learning rules. 0
Andersen; Hippocampus Book 618 (4) Sites of storage: spatial maps are stored in the hippocampus. They are not consolidated are stored elsewhere in the brain, although information stored in the hippocampus does interact with information stored elsewhere for the purpose of guiding navigational behavior. 0
Andersen; Hippocampus Book 618 (5) Extension of the theory to humans: where is the cognitive map is purely spatial in animals, in sub serves as storage and recall of linguistic and episodic memories in humans. 0
Andersen; Hippocampus Book 620 Development of multiple single-unit recording ("ensemble recording"). 2
Andersen; Hippocampus Book 620 Pyramidal cells acquire their place feels rapidly, fire in proportion to an animal speed of motion, and show temporal precision in their phase relation to the hippocampal theta as animal moves through the cells place field. 0
Andersen; Hippocampus Book 620 Place fields represent probability distributions and do not specify precise locations. 0
Andersen; Hippocampus Book 620 The hippocampal formation and interconnect being structures constitute, in animals, an essentially spatial system. 0
Andersen; Hippocampus Book 620 The relation between location firing (in pyramidal cells of CA1 and CA3), head-directional firing (in the presubiculum and anterior thalamus), and movement firing (in the interneurons of the hippocampus and dentate gyrus) is poorly understood. 0
Andersen; Hippocampus Book 620 Spatial mapping has evolved in response to specific environmental demands, and constitute one of the multiple memory system of the vertebrate brain. 0
Andersen; Hippocampus Book 620 Cache recovery in passerine birds, homing in pigeons, territory size and mapping systems in small mammals and other aspects of naturalistic spatial behavior. 0
Andersen; Hippocampus Book 621 The bulk of the work addressing the cognitive map theory has been conducted with the laboratory rat. 1
Andersen; Hippocampus Book 621 The relevance of the cognitive map theory of hippocampal function extended to human semantic memory and, specifically, the way in which spatial relations are fundamental to certain linguistic prepositions that reflect a knowledge of relations (e.g. "beside,"    "near,"    "above"). 0
Andersen; Hippocampus Book 622 Space is not a sensory modality. We do not have sensory organs for space. 1
Andersen; Hippocampus Book 622 Space is a construct of mental processing. 0
Andersen; Hippocampus Book 642 Homing Pigeons Reveal Hippocampus-dependent and Hippocampus-independent Components of Navigation 20
Andersen; Hippocampus Book 650 Storage and Consolidation of Spatial Memory 8
Andersen; Hippocampus Book 655 Integrity at the Hippocampus Is Required for Many Non-Spatial Learning Tasks 5
Andersen; Hippocampus Book 662 A significant feature of memory is the ability to recall facts and events and circumstances different from those in which the information was acquired in the first place. 7
Andersen; Hippocampus Book 662 Relational Processing Theory 0
Andersen; Hippocampus Book 662 Declarative Memory generally involves processing the relations between different items. 0
Andersen; Hippocampus Book 662 Relational processing at encoding enables flexible access to information and situations    quite different from those of the original learning. 0
Andersen; Hippocampus Book 662 Relational processing is carried out by the old capital formation, but storage at individual items in immediate memory takes place in a perrirhinal and parahippocampal cortex. 0
Andersen; Hippocampus Book 662 The role of the hippocampus in memory is temporary, as in the declarative memory theory. 0
Andersen; Hippocampus Book 663 Relational Processing Theory -- Processes and Anatomical Mediation (diagram) 1
Andersen; Hippocampus Book 663 Three functional component of the relational processing memory system 0
Andersen; Hippocampus Book 663 (1) Cortical areas store short-term memory and long-term memory traces of specific items. 0
Andersen; Hippocampus Book 663 (2) The parahippocampal regions serves as an intermediate memory for specific items and does the job of cue compression. 0
Andersen; Hippocampus Book 663 (3) The hippocampal formation computes relational representations in a manner that enables representational flexibility. 0
Andersen; Hippocampus Book 672 Patient HM was unable to report whether he was hungry. 9
Andersen; Hippocampus Book 672 Patient HM did not ask for meals    and, quite soon after eating, attempted to eat again if a plate of food was placed before him. 0
Andersen; Hippocampus Book 677 Concept of episodic memory was first introduced by Tulving (1972) and elaborated in a number of ways. 5
Andersen; Hippocampus Book 677 Episodic memory refers to the memory of a unique event and/or a temporary sequence of events that collectively comprise an episode. 0
Andersen; Hippocampus Book 677 Hippocampus -- Episodic and Episodic-like Memory 0
Andersen; Hippocampus Book 677 Episodic memory is the recall, by humans, of discrete events that happened any particular place in a particular time. Such recall in tales of mental time travel. 0
Andersen; Hippocampus Book 677 Episodic-like memory in animals is the memory of "what, where, and when" with respect to events. 0
Andersen; Hippocampus Book 677 The hippocampus is one of a network of brain structures that mediate the automatic encoding and retrieval of attended events and the contexts in which they occur (episodic-like memory). 0
Andersen; Hippocampus Book 677 Components of the hippocampus formation (e.g. CA1, CA3, dentate gyrus) are differentially involved in dissociable components of episodic-like memory, such as pattern separation and pattern completion. 0
Andersen; Hippocampus Book 677 Episodic memory and episodic-like memory are distinguishable, as only the former requires "autonoetic" consciousness. 0
Andersen; Hippocampus Book 715 Computational Models of the Spatial and Mnemonic Functions of the Hippocampus 38
Andersen; Hippocampus Book 716 Computational modeling of the hippocampus has followed two largely independent streams over the years: one seeking to explain a general role in associative memory and the other focusing on its role in spatial navigation. 1
Andersen; Hippocampus Book 716 Activity (firing rate) of a neuron is viewed as a monotonic function of the amount by which the net input to the neuron    exceeds    some threshold value. 0
Andersen; Hippocampus Book 716 Learning is of a Hebbian nature such that simultaneous pre- and post-connection activity leads to increased connection strength    and is often used in explicit analogy to synaptic processes such as long term potentiation (LTP). 0
Andersen; Hippocampus Book 716 Anatomy in the hippocampal region is similar in rats,    primates,    and humans. 0
Andersen; Hippocampus Book 716 Place cells in the neural representation of space draws mostly on experimental data collected in rats. 0
Andersen; Hippocampus Book 716 The general role of the human hippocampus in memory for personal experience. 0
Andersen; Hippocampus Book 722 Attractors in Memory, Neural Coding, and Path Integration 6
Andersen; Hippocampus Book 722 A network of recurrently connected neurons can be arranged so a finite number of discrete patterns of activation across the neurons are stable states or "attractors." 0
Andersen; Hippocampus Book 727 Phase coding of place cell firing with the respect to the concurrent theta rhythm of the EEG    (O'Keefe) 5
Andersen; Hippocampus Book 727 The theta rhythm is a large-amplitude oscillation of around 6 to 10 Hz of the EEG    and is present whenever the rat is moving its head    through the environment. 0
Andersen; Hippocampus Book 733 Hippocampus and Associative or Episodic Memory 6
Andersen; Hippocampus Book 733 Amnesia is the major impairment noted in humans following bilateral damage to the hippocampus. 0
Andersen; Hippocampus Book 733 Because only a relatively small number of cases of damage restricted to the hippocampus have been studied, it is difficult to draw general conclusions regarding its role in memory. 0
Andersen; Hippocampus Book 733 Hippocampus is typically result in a ubiquitous deficit in memory for personally experienced the events that occur after the lesion, and spared procedural and working memory. 0
Andersen; Hippocampus Book 734 Events in the outside world are represented by patterns of activity in neocortical areas. (Marrs 1971 model) 1
Andersen; Hippocampus Book 734 The role of the hippocampus is to store representations over the short term so relevant events can be categorized and stored for the long term in neocortex. 0
Andersen; Hippocampus Book 734 The neocortical representation of an event is mapped into a "simple representation" in the hippocampus, with modifiable connections to and from the hippocampus storing the mappings between the full representation in the simple representation. 0
Andersen; Hippocampus Book 734 The CA3 recurrent or lateral some modified to store the simple representation as an associative memory -- if a simple representation is incompletely activated, the "collateral effect" results in the full representation being recovered. 0
Andersen; Hippocampus Book 734 Partial activation of the neocortical representation of an event can lead to complete activation of its simple representation in the hippocampus, which in turn can reactivate the entire neocortical representation. 0
Andersen; Hippocampus Book 734 The capacity at the hippocampus system should be enough to store a day's events so the process of categorization and long-term storage in new cortex can take place during the following night's sleep. 0
Andersen; Hippocampus Book 734 Simple representations in the hippocampus should be sparsely encoded to reduce possible interference between representations. 0
Andersen; Hippocampus Book 734 The associated properties that the following networks and recurrent networks are based on Hebbian learning. 0
Andersen; Hippocampus Book 735 Biological implementation of associative memory in the hippocampus (diagram) 1
Andersen; Hippocampus Book 736 Anatomy of the inputs to CA3 pyramidal cells, showing the approximate number of synapses onto each cell in the rat. (Treves and Rolls)  (diagram) 1
Andersen; Hippocampus Book 736 Hippocampal anatomy and a computation model of hippocampal episodic memory function. (diagram) 0
Andersen; Hippocampus Book 737 Hippocampal Representation, Context, and Novelty 1
Andersen; Hippocampus Book 738 Consolidation and Cross Modal Binding of Events in Memory 1
Andersen; Hippocampus Book 738 How the hippocampus contributes to the long-term consolidation of memories. 0
Andersen; Hippocampus Book 738 The day's events are stored in the hippocampus,    and this information is used to allow a long-term categorization    and storage in the neocortex. 0
Andersen; Hippocampus Book 738 The hippocampus store of unprocessed experience has a limited capacity, and the process of extracting relevant information from this experience to expand a long-term database requires extensive off-line processing, perhaps during sleep. 0
Andersen; Hippocampus Book 738 Anatomical convergence of information from different sensory modalities at the hippocampus. 0
Andersen; Hippocampus Book 738 Associations between the elements of an event, such as its sight,    sound,   and smell.    Damasio has suggested that "convergent zones" must exist where these associations could be formed. 0
Andersen; Hippocampus Book 739 Hippocampal Contributions to Various Types of Memory and Retrieval 1
Andersen; Hippocampus Book 744 The ability to specify a proposed mechanism of hippocampal function in terms of a computational model is invaluable in many ways 5
Andersen; Hippocampus Book 744 Many questions for future research are prompted by computational models. 0
Andersen; Hippocampus Book 744 Any worthwhile theory must make potentially falsifiable predictions. 0
Andersen; Hippocampus Book 744 Investigating the link between the properties of cells interacting a complex system such as the brain to the resulting behavior of an animal would become almost impossible without the aid of computational models. 0
Andersen; Hippocampus Book 751 Stress and the Hippocampus 7
Andersen; Hippocampus Book 769 Hippocampus and Human Disease 18
Andersen; Hippocampus Book 770 Temporal Lobe Epilepsy 1
Andersen; Hippocampus Book 789 Alzheimer's Disease 19
Andersen; Hippocampus Book