Edelman and Mountcastle - Mindful Brain
Book Page   Topic    
Mountcastle; Organizing Cerebral Function 10 The number of neurons in a vertical lines across the thickness of the cortex, i.e. a 30 diameter cylinder, is remarkably constant at about 110.
Mountcastle; Organizing Cerebral Function 11 All of the cells destined for the neocortex arise from the ventricular and subventricular zones of the neural tube during the gestation period. 1
Mountcastle; Organizing Cerebral Function 11 Cells that arise early, mainly from the ventricular zone, may move over their short migratory trajectories of 200 to 300 by extension of a process and nuclear translocation. 0
Mountcastle; Organizing Cerebral Function 11 Cells arising later must migrate over distances of up to 10 mm; they are guided to their final positions by moving along the surfaces of radially oriented glial cells, which extends across the entire wall of the neural tube. 0
Mountcastle; Organizing Cerebral Function 11 Cortical cells are arranged in radially oriented cords or columns extending across the cortex. 0
Mountcastle; Organizing Cerebral Function 14 A cortical area may be defined both by its (1) intrinsic structure and as (2) the zone of projection of a specific thalamic nucleus. 3
Mountcastle; Organizing Cerebral Function 15 Cytoarchitectural differences between areas of neocortex reflect differences in their patterns of extrinsic connections. 1
Mountcastle; Organizing Cerebral Function 15 It is apparent that neocortex is everywhere functionally uniform and that it's progressive enlargement in mammals and particularly in primates has been accomplished by replication of a basic neural module, without the appearance of a wholly new neuron types or qualitatively different modes of intrinsic organization. 0
Mountcastle; Organizing Cerebral Function 37 Basic modular unit of the neocortex is a minicolumn. 22
Mountcastle; Organizing Cerebral Function 37 Minicolumn is a vertically oriented cord of cells formed by the migration of neurons from the germinal epithelium of the neural tube along the radial glial cells to their destined location in the neocortex. 0
Mountcastle; Organizing Cerebral Function 37 Minicolumn contains about 110 cells. This figure is almost invariant between different neocortical areas and different species of mammals, except for the striate cortex of primates, where it is 260. 0
Mountcastle; Organizing Cerebral Function 37 Minicolumn of cells forms a vertical cylinder with a diameter of about 30 m. 0
Mountcastle; Organizing Cerebral Function 37 Since the total volume of the human neocortex is about 1000 cm3, and assuming an average thickness of 2,500 m, neocortex of the human brain has a surface area of about 4,000 cm2 and contains about 600 million minicolumns and on the order of 50 billion neurons. 0
Edelman; Group Selection and Reentrant Signaling 74 Role of the reticular formation for arousal indicates that there are areas of the brain outside of the cortex that necessary for consciousness. 37
Edelman; Group Selection and Reentrant Signaling 81 Minimal activation period of about 200-500 ms for awareness of a near-threshold stimulus. 7
Edelman; Group Selection and Reentrant Signaling 81 Studies end experimental psychology suggest that a full perception requires no more than 100 ms of intracortical processing time. 0
Edelman; Group Selection and Reentrant Signaling 81 The brain functions for action. 0
Edelman; Group Selection and Reentrant Signaling 82 Central programming of motor patterns is predominant over simple reflex patterns. 1
Edelman; Group Selection and Reentrant Signaling 82 Hippocampal function in attentional states is related to the performance of motor acts. 0
Edelman; Group Selection and Reentrant Signaling 88 Early in development, cell groups or polyclones are determined by gene expression and programming. 6
Edelman; Group Selection and Reentrant Signaling 88 Large degeneracy is built into the system. Many more cell groups than are ultimately used to make projections and connections. Many of the "unused" cells die. 0
Edelman; Group Selection and Reentrant Signaling 88 A hierarchy of interactions occurs, with early decisions (such as branching of limb plexus neurons) being relatively few in number and decided by the gene program. 0
Edelman; Group Selection and Reentrant Signaling 88 Interaction between cell groups are sequential, selective, and determined by mutual influence. 0
Edelman; Group Selection and Reentrant Signaling 88 Result of selective interaction is the loss of synaptic connections and the death of many CNS neurons during development. 0
Edelman; Group Selection and Reentrant Signaling 89 Enormous degeneracy and selection early in the system, even before primary repertoire formation is complete. 1
Edelman; Group Selection and Reentrant Signaling 89 Later developments, such as those in critical periods, may reduce degeneracy by selective synaptic stabilization. 0
Edelman; Group Selection and Reentrant Signaling 89 Prefrontal, frontal, and temporal cortices have a constantly extended critical period, which in fortunate individuals may be delayed until death. 0
Edelman; Group Selection and Reentrant Signaling 90 Central pattern generators and autonomous reflexes can give rise to a highly adaptive and complex forms of behavior. [Stereotyped motor programs] [FAPs] 1
Edelman; Group Selection and Reentrant Signaling 92 Groups of cells, not single cells, are the main unit of selection in higher brain functions. 2
Edelman; Group Selection and Reentrant Signaling 92 Groups of cells in higher brain functions will be found to be multiply represented, degenerate, and isofunctionally overlapping. 0
Edelman; Group Selection and Reentrant Signaling 93 Although single neurons may occasionally function as a group, no pontifical neuron or single-neuron "decision unit" will ever be found at the highest level of a system of any large degree of plasticity. 1
Edelman; Group Selection and Reentrant Signaling 93 Correlations will be found that suggest phase reentrant signaling on degenerate neuronal groups with periods of 50-200 ms. 0
Edelman; Group Selection and Reentrant Signaling 93 The most likely correlations will be found between cortical, thalamocortical, and limbic-reticular signals. 0
Edelman; Group Selection and Reentrant Signaling 94 Properties of the central nervous system -- (1) distributed nature of learning, (2) associative nature of recall, (3) adaptive reaction to novelty, capacity to make (4) highly abstract representations in a world model. 1
Edelman; Group Selection and Reentrant Signaling 94 Structured neuronal groups containing up to 10,000 neurons are formed during embryogenesis and development. Intrinsic connections within a group and extrinsic connections among groups are specified by gene programming and synaptic selection. 0
Edelman; Group Selection and Reentrant Signaling 94 Consciousness includes the ability to accumulate memories and to recall them associatively in temporal sequences. 0
Edelman; Group Selection and Reentrant Signaling 94 Consciousness includes the capacity to distinguish self from nonself (self-awareness). 0
Edelman; Group Selection and Reentrant Signaling 95 The conscious state results from phasic reentrant signaling occurring in parallel processes that involve associations between stored patterns and current sensory or internal input. 1
Edelman; Group Selection and Reentrant Signaling 95 Awareness is assumed to arise as a result of the access by groups of higher order neurons to rich multimodal associative patterns stored in long-term memory as a result of past experience. 0
Edelman; Group Selection and Reentrant Signaling 95 Sequential tagging of stored events allows for recall in a proper time scale and order. 0
Edelman; Group Selection and Reentrant Signaling 95 Because of the selective, group-degenerate, and phasic nature of reentrant cycles and the capacity of higher-order neurons to abstract sequences of events, a continuous shifting pattern of associations can be made. [Fuster's perception-action cycle] 0
Edelman; Group Selection and Reentrant Signaling 95 Consciousness is considered to be a form of associative recollection with updating, based on present reentrant input, that continually confirms or alters a "world model" or "self" by means of parallel motor or sensory outputs. [recursion] [Bayesian inference] [Fuster's perception-action cycle] 0
Edelman; Group Selection and Reentrant Signaling 95 Brain's entire neurological process depends upon the properties of group selection and reentrant signaling in a nervous system that is already specified by embryological, developmental, and evolutionary events. 0
Edelman; Group Selection and Reentrant Signaling