Traub
& Whittington; Cortical Oscillations |
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Traub; Cortical Oscillations |
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Recent Developments in Cortical
Oscillations |
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Traub; Cortical Oscillations |
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Earlier work (1999) was almost entirely concerned with
gamma (30-70 Hz) and beta (10-30 Hz) oscillations evoked in hippocampal
slices by tetanic
stimulation, with a special emphasis on long-range synchrony of the oscillations. |
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Traub; Cortical Oscillations |
6 |
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Neurotransmitters/neuromodulatory substances act on a variety of receptors, both ionotropic (phasic) and metabotropic (slower, or tonic). |
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Traub; Cortical Oscillations |
6 |
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Large, slow,
excitatory postsynaptic potentials (EPSPs) develop in pyramidal neurons as well as in interneurons, mediated in large part by metabotropic
glutamate receptors. |
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Traub; Cortical Oscillations |
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Superimposed
on the slow EPSPs are
trains of fast
inhibitory postsynaptic potentials (IPSPs). |
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Traub; Cortical Oscillations |
6 |
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Locally synchronized network oscillations develop
after a latent period
of 50 to several
hundred milliseconds, at gamma
frequencies,
and lasting for hundreds of milliseconds. |
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Traub; Cortical Oscillations |
6 |
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Both the latent
period and the duration of the electrically invoked gamma
oscillations are
similar to those observed in visual-neocortical
gamma oscillations in vivo evoked by a stimulus such as a moving
grating at appropriate
orientation. |
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Traub; Cortical Oscillations |
8 |
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Long-range synchrony of gamma
oscillations and interneuron doublets in a rat dorsal hippocampal slice
(diagram) |
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Traub; Cortical Oscillations |
12 |
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There are at least three reasons
to study cortical
oscillations:
(1)
they may play a role in normal brain
functions, cognition, and especially sleep; (2) they play a role in neuropsychiatric disorders such as
epilepsy,
schizophrenia, Parkinson's
disease,
and cerebellar ataxia; (3) study of
oscillations has enriched cellular neurobiology with respect to gap junctions,
synaptic mechanisms, and intrinsic neuronal membrane
physiology. |
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Traub; Cortical Oscillations |
12 |
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Very fast oscillations (70-80
Hz) can be generated in conditions of chemical synaptic
blockade, but also occur in other conditions as well. |
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Traub; Cortical Oscillations |
12 |
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Persistent gamma oscillations,
which could be related to abnormal epileptiform activity. |
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Traub; Cortical Oscillations |
12 |
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Beta-2 oscillations, at about 25
Hz, are generated in large tufted pyramidal neurons of layer 5 of the
cerebral cortex. |
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Traub; Cortical Oscillations |
12 |
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Mixtures of oscillations occur
during epileptogenesis. |
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Traub; Cortical Oscillations |
13 |
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What all the diverse
types of oscillations have in common is electrical coupling via gap junctions. |
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Traub; Cortical Oscillations |
13 |
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Most or all of the somatic
action potentials originate in axons and then propagate antidromically (as
well as orthodromically). |
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Traub; Cortical Oscillations |
13 |
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Fast oscillations are generated by axonal action
potentials occurring either spontaneously (ectopically), or as
a result of action potentials in electrically
coupled axons -- and not
as a result of synaptic
input to the soma and dendrites. |
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Traub; Cortical Oscillations |
13 |
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Synaptic integration -- the
postulate that neuronal firing is a consequence of synaptic inputs to cells,
is a classic (and very deeply ingrained) concept that pervades all of
neuroscience. |
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Traub; Cortical Oscillations |
13 |
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In epilepsy, why so many sorts of oscillations -- at widely different frequencies
-- are associated with the epoch before a seizure, as well as during the seizure itself. |
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Traub; Cortical Oscillations |
13 |
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For schizophrenia, sensory stimulation evokes gamma followed
by beta oscillations in the intact human
brain, but the "habituation" properties of the beta portion are different in schizophrenics as compared with nonschizophrenics. |
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Traub; Cortical Oscillations |
13 |
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In Parkinson's
disease,
the symptomatic disease is correlated with enhanced beta oscillations (15-30 Hz) in a number of
locations
within the basal ganglia, and L-DOPA treatment, which elevates
dopamine
concentration within the brain, attenuates the beta activity as it relieves symptoms. |
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Traub; Cortical Oscillations |
14 |
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For cerebellar
ataxia,
it is premature to draw firm conclusions about the importance of brain
oscillations for ataxia, even though there must be some connection. |
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Traub; Cortical Oscillations |
14 |
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The best-known cerebellar oscillations consists
of localized regions of 4-10 Hz rhythms that are generated in the inferior olive and projected to the cerebellum via the climbing fibers. |
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Traub; Cortical Oscillations |
14 |
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Faster
oscillations occur in the cerebellum, and have some degree of coherence with oscillations in other parts of the motor system
(portions of the thalamus, basal ganglia, and cerebral cortex). |
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Traub; Cortical Oscillations |
14 |
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Both gamma and very fast oscillations have been generated in cerebellar cortex slices, with very fast oscillations occurring at 100 to 200 Hz, being produced by electrical coupling. |
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Traub; Cortical Oscillations |
14 |
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Table of
frequency ranges of various
oscillations (table) |
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Traub; Cortical Oscillations |
15 |
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Do not use the term "gamma" for oscillations above 80 Hz because these are presumed not gated primarily by IPSPs. |
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Traub; Cortical Oscillations |
15 |
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The term "gamma" should be reserved for oscillations
gated by inhibitory postsynaptic potentials
(IPSPs). |
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Traub; Cortical Oscillations |
56 |
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Working memory (in prefrontal, parietal, and inferior temporal cortex)
is
apparently associated with the activation of selected brain regions; and within these regions, there
appears to be an additional selection of some neurons that fire at high rates. |
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Traub; Cortical Oscillations |
56 |
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In addition to localized
cortical activation, there are global cortical activated epochs (each lasting
hundreds of milliseconds, and with hundreds-of-milliseconds to seconds
separation between epochs), that occur during the slow (~1 Hz) oscillation of
sleep. |
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Traub; Cortical Oscillations |
57 |
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Absence of firing in the hyperpolarized state ("downstate"). |
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Traub; Cortical Oscillations |
58 |
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Fast oscillations are coherent between thalamus and cortex. |
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Traub; Cortical Oscillations |
58 |
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Fast oscillations during slow wave sleep as spatially limited coherence. |
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Traub; Cortical Oscillations |
60 |
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"Standard" models of neuronal networks are based on the assumption that timing is determined by membrane depolarization
and
the pattern of synaptic
inputs. |
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Traub; Cortical Oscillations |
60 |
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Action potentials can be generated in axons, influenced in large part by action potentials in electrically coupled axons. |
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Traub; Cortical Oscillations |
60 |
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The slow
oscillation of sleep correlates with the occurrence of certain EEG patterns (delta waves). |
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Traub; Cortical Oscillations |
60 |
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During slow wave sleep, we do
not see rapid eye movements, skeletal muscular paralysis, or continuous EEG
fast rhythms. |
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Traub; Cortical Oscillations |
63 |
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Very Fast Oscillations
Superimposed on Sensory Evoked Potentials |
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Traub; Cortical Oscillations |
63 |
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Free sensory stimulation, and
any modality, evokes a series of neural responses in cortical structures, and
early (<~150 ms) and it longer (<~500 ms) latencies, typically
consisting of waves that last on the order of tens of milliseconds. |
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Traub; Cortical Oscillations |
63 |
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Neural responses to brief
sensory stimulation are produced as neural "traffic" proceeds along
axons, causing cell firing and then synaptic currents, and in turn influenced
successive pools of neurons. |
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Traub; Cortical Oscillations |
63 |
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Synchronized epileptiform
bursts can be regarded as a type of internally generated evoked
response. |
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Traub; Cortical Oscillations |
63 |
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Neuronal population responses lasting tens of milliseconds often have very fast oscillations superimposed upon them. |
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Traub; Cortical Oscillations |
63 |
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In vivo hippocampal physiological sharp waves contain superimposed "ripples" at about 200 Hz. |
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Traub; Cortical Oscillations |
63 |
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It is critical to understand the
relation between the slower
spontaneous or evoked
responses -- which are attributed to synchronized synaptic currents --
and the very fast oscillations that are superimposed. |
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Traub; Cortical Oscillations |
64 |
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Very fast oscillations (~390 Hz in this instance) occur superimposed on somatosensory evoked response in rat barrel cortex. (diagram) |
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Traub; Cortical Oscillations |
66 |
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Temporal Interactions between
Cortical Oscillations in Different Frequencies |
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2 |
Traub; Cortical Oscillations |
66 |
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Oscillations can be superimposed
on transient neuronal population events, and also on particular phases of
another, slower, oscillation. |
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Traub; Cortical Oscillations |
66 |
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Perhaps the best-known example
of one oscillation superimposed
on, and amplitude modulated, by
another is the case of gamma oscillations superimposed on the hippocampal theta rhythm. |
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Traub; Cortical Oscillations |
66 |
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Understanding how interactions take place between oscillations at different frequencies may be
important for unraveling the functional importance of each frequency, and how the respective distinct functions might be interrelated. |
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Traub; Cortical Oscillations |
66 |
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The cortical beta-1 (~15 Hz)
oscillation appears to be produced by fitting together (rather than
phase-resetting or amplitude-modulating) two simpler oscillations. |
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Traub; Cortical Oscillations |
67 |
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Cerebellar Oscillations |
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1 |
Traub; Cortical Oscillations |
67 |
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The cellular
mechanisms of cerebellar
oscillations provide
interesting contrasts with mechanisms of neocortical
oscillations at comparable frequencies, because
the synaptic architecture of cerebral and cerebellar cortices is so different. |
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Traub; Cortical Oscillations |
67 |
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Oscillations
at theta and alpha frequencies are generated among the electrically coupled
pool of inferior olivary neurons, and transmitted to the deep cerebellar nuclei in cerebellar cortex via climbing fibers. |
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0 |
Traub; Cortical Oscillations |
67 |
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Auditory
evoked activity contains fast oscillations. (diagram) |
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Traub; Cortical Oscillations |
68 |
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Example of one oscillation
(delta) modulating the amplitude of another (theta). |
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1 |
Traub; Cortical Oscillations |
69 |
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Beta and gamma (as well as lower
frequency) oscillations are generated within the cerebellar cortex. |
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1 |
Traub; Cortical Oscillations |
70 |
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Epilepsy |
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1 |
Traub; Cortical Oscillations |
105 |
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Parkinson's Disease |
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35 |
Traub; Cortical Oscillations |
105 |
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The most critical discovery
about Parkinson's disease
concerned elucidation of the role of dopamine deficiency in causing many of the
signs and symptoms. |
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Traub; Cortical Oscillations |
105 |
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The discovery of dopamine deficiency in Parkinson's disease led to a range of related pharmacological treatments that are close to
miraculous, but ultimately
frustrating, because of disease progression, failure to maintain desired clinical actions, and the emergence of troubling side effects. |
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Traub; Cortical Oscillations |
105 |
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Parkinson's Disease therapy via implanted device intended for long-term "deep brain stimulation"
(DBS). |
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Traub; Cortical Oscillations |
106 |
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"Parkinsonism," a clinical constellation of signs and symptoms, with "Parkinson's Disease" referring to a characteristic clinical syndrome
with a characteristic underlying neuropathology. |
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Traub; Cortical Oscillations |
106 |
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The most characteristic clinical features of Parkinson's disease include a rest tremor
(that may initially be voluntarily suppressable,
and tends to diminish with intentional movement), muscle
rigidity,
slowing of movement (bradykinesia -- in its extreme
form, akinesia), and a characteristically impaired gait. |
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0 |
Traub; Cortical Oscillations |
106 |
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Later in Parkinson's disease,
postural instability, freezing, and falls can constitute major problems. |
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Traub; Cortical Oscillations |
106 |
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In Parkinson's
disease,
immobility
eventually results in confinement to chair and then to bed, as well as difficulty swallowing and clearing
secretions. |
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Traub; Cortical Oscillations |
107 |
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Dopamine was discovered in the
brain (1957) |
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Traub; Cortical Oscillations |
109 |
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Organizational Principles of the
Basal Ganglia |
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2 |
Traub; Cortical Oscillations |
110 |
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Some Effects of Dopamine in the
Brain |
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Traub; Cortical Oscillations |
115 |
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Dopamine and Gap Junctions |
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5 |
Traub; Cortical Oscillations |
116 |
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Experimental Models of
Parkinson's Disease |
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1 |
Traub; Cortical Oscillations |
116 |
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How is it that dopamine
depletion in the brain leads to so many of the signs and symptoms of
Parkinson's disease. |
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Traub; Cortical Oscillations |
117 |
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Parkinson's disease in humans is
associated with a loss of norepinephrine neurons (e.g. in locus coeruleus) as
well as dopaminergic neurons. |
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1 |
Traub; Cortical Oscillations |
117 |
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The Subthalamic Nucleus |
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0 |
Traub; Cortical Oscillations |
117 |
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One of the most
effective nonpharmacological treatments of Parkinson's disease consists of chronic high-frequency
stimulation,
via an implanted device, of one or both subthalamic nuclei: a so-called deep brain stimulation (DBS) technique. |
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Traub; Cortical Oscillations |
117 |
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This subthalamic
nucleus consists of glutamatergic
cells with rather complex properties, which are able to fire in at
least four different modes: a silent
hyperpolarized mode, a depolarized
plateau,
tonic firing of
single spikes, and rhythmic
slow bursts. |
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0 |
Traub; Cortical Oscillations |
117 |
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It is not clear if subthalamic neurons interact with each other directly, either through chemical synapses or through gap junctions. |
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0 |
Traub; Cortical Oscillations |
117 |
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Gamma oscillations at 46 to 70 Hz have been recorded in subthalamus. |
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0 |
Traub; Cortical Oscillations |
123 |
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Schizophrenia |
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6 |
Traub; Cortical Oscillations |
123 |
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Schizophrenia
is diagnosed by clinical presentation and evolution; it is particularly important to recognize
a clear sensorium in the patient and to exclude
psychotic states induced by drugs and by neurological disorders, especially
disorders that may have specific treatments (such as encephalitis). |
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0 |
Traub; Cortical Oscillations |
123 |
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No particular laboratory tests
-- including imaging, CSF analysis, EEG, and molecular genetic tests --
clenches the diagnosis. |
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0 |
Traub; Cortical Oscillations |
123 |
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Schizophrenia
is defined predominantly by how patients behave, particularly about
what they say and write, and how they seem to think. |
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0 |
Traub; Cortical Oscillations |
124 |
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Schizophrenia
is associated with a decline in many aspects of cognitive
functions.
Perceptual disorganization and working memory deficits figure prominently. |
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1 |
Traub; Cortical Oscillations |
125 |
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Hallucinations and thought disorder in schizophrenic patients are complemented by
examples revealing more specific aspects of disrupted
Gestalt processes: limitations in perceptions of a whole sensory object through combination of a set of smaller, simpler
features. |
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1 |
Traub; Cortical Oscillations |
125 |
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Only in the early 20th century
did Alois Alzheimer (1964-1915), using staining techniques, define the
characteristic neuropathology of the dementing disease: neuronal loss, senile
(amyloid) plaques, and neurofibrillary tangles. |
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0 |
Traub; Cortical Oscillations |
126 |
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Schizophrenia
was previously called dementia praecox, emphasizing what was considered to be the usual course of a progressive mental disability. |
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1 |
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126 |
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"Schizophrenia"
derives from the Greek, meaning "splitting of the mind" -- not in
the sense of split personality (generally a manifestation of hysteria), but
in what was considered a fragmentation of the psyche, a concept difficult to
nail down precisely. |
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Traub;
Cortical Oscillations |
126 |
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The cardinal
clinical manifestations of schizophrenia include delusions, that may be grandiose or persecution; abnormal
perceptions, including auditory
hallucinations in the form of internal voices speaking to the
patient, perhaps commenting on him or her;
formal thought disorder, in which the patient's trains of
thought are difficult
or impossible to follow; motor,
volitional, and behavioral disorders, including catatonia (immobility and mutism,
perhaps with automatic following of commands), mannerisms and stereotypic
repeated behaviors; and emotional disorders, including flattened or inappropriate affect, and withdrawal. |
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0 |
Traub; Cortical Oscillations |
126 |
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Schizophrenia
has acute and chronic presentations and courses. |
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0 |
Traub; Cortical Oscillations |
126 |
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Schizophrenia
exhibits positive symptoms, such as hallucinations, and negative symptoms, such as apathy, muteness, and social withdrawal. |
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0 |
Traub; Cortical Oscillations |
127 |
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Estimates of the prevalence of schizophrenia vary, but one careful review suggests 0.4%, similar to the prevalence of
epilepsy. |
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1 |
Traub; Cortical Oscillations |
127 |
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Schizophrenia
most often (certainly not always) strikes in adolescence and young
adulthood,
and can be relapsing/remitting or progressive -- characteristics shared with multiple
sclerosis. |
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0 |
Traub; Cortical Oscillations |
128 |
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Schizophrenia
is a genetic disorder,
in large part. |
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1 |
Traub; Cortical Oscillations |
152 |
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Cerebellar Ataxia |
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24 |
Traub; Cortical Oscillations |
152 |
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The principal cell type of the
cerebellum, the Purkinje cell, is susceptible to anoxia and other biochemical
and metabolic stresses, and once lost, these cells are not replaced. |
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0 |
Traub; Cortical Oscillations |
152 |
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Multiple sclerosis is a common
neurological disease (prevalence ~1.0 cases per 1000 population), with ataxia
and tremor. |
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0 |
Traub; Cortical Oscillations |
152 |
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Cerebellar ataxia and tremor
are, in almost all cases, extremely difficult to treat. |
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0 |
Traub; Cortical Oscillations |
152 |
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Ataxia and tremor can be so
disabling as to make a patient bedfast, unable to speak or swallow, and
completely dependent on caregivers. |
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0 |
Traub; Cortical Oscillations |
153 |
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The phenomenology of cerebellar
disorders has been described exhaustively, but the underlying pathophysiology
remains largely mysterious. |
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1 |
Traub; Cortical Oscillations |
153 |
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Ataxia is notable in learned
complex movements of the limbs and articulation, but gait and eye movements
can also be ataxic. |
|
0 |
Traub; Cortical Oscillations |
153 |
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Tremor, especially with movement
such as reaching or grasping, but possibly also with holding posture, is a
symptom of major focal cerebellar injury. |
|
0 |
Traub; Cortical Oscillations |
153 |
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Most movements in humans involve
smooth interaction of flexions and extensions (and sometimes rotations)
across several joints, both within a given limb (e.g. shoulder, elbow, and
wrist), and between limbs (swinging the arms and legs in proper relative phases
during walking). |
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0 |
Traub; Cortical Oscillations |
153 |
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The decomposition of smooth
interactions flexions and extensions in limbs and joints may fail with
cerebellar disease, to be replaced but not by paralysis, but by a less
elegant performance, so that one joint carries out its action, then the next,
then the next . . . decomposition. |
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0 |
Traub; Cortical Oscillations |
154 |
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The cerebellum is not sufficient
by itself to produce movements, but it is necessary for movements --
especially complicated ones, involving many joints or muscles -- to be
executed smoothly and in coordinated fashion. |
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1 |
Traub; Cortical Oscillations |
154 |
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The cerebellum is particularly
required when sensory input (visual, proprioceptive, vestibular, alone or in
combination) is helping to guide the movement. |
|
0 |
Traub; Cortical Oscillations |
154 |
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The cerebellum is intimately
interconnected with a number of other important paired structures, including
the inferior olive in the medulla, the red nucleus in the midbrain, the
vestibular nuclei in the medulla, and perhaps most critically, the deep cerebellar
nuclei. |
|
0 |
Traub; Cortical Oscillations |
155 |
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Prominent existence of gap
junctions in the inferior olive and vestibular nuclei, and a marked tendency
of the inferior olive to generate its own oscillations, whose synchrony
depends on gap junctions. |
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1 |
Traub; Cortical Oscillations |
157 |
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Purkinje cells, the principal
neuron of the cerebellar cortex, receiving two distinct types of excitatory
afferent, as well as GABAergic input from other cerebellar neurons. |
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2 |
Traub; Cortical Oscillations |
157 |
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Purkinje cells themselves are
GABAergic (inhibitory). |
|
0 |
Traub; Cortical Oscillations |
157 |
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The Purkinje cell has an
extensive dendritic arborization, with a proximal smooth (nonspiny) portion,
and innumerable spiny branchlets that receive, in total, more than 100,000
excitatory synapses (although many or most of the synapses are probably "silent"). |
|
0 |
Traub; Cortical Oscillations |
157 |
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The dendrites of Purkinje cells
are lie roughly in a plane, and the dendritic planes of nearby Purkinje cells
are nearly parallel, and orthogonal to the axis of the local folium. |
|
0 |
Traub; Cortical Oscillations |
157 |
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There are an estimated 340,000
Purkinje cells in rat cerebellum. Their somata lie in a single layer, the
Purkinje cell layer. |
|
0 |
Traub; Cortical Oscillations |
157 |
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The region inhabited by the
Purkinje cell dendrites is called the "molecular layer", and the
region just below the Purkinje stomata, through which the Purkinje axons
pass, is call the "granular layer". |
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0 |
Traub; Cortical Oscillations |
160 |
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Lack of Recurrent Synaptic
Excitation within This Cerebellar Cortex |
|
3 |
Traub; Cortical Oscillations |
160 |
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Most of the synapses within the
cerebral cortex are excitatory synapses lying on excitatory neurons. With
suppression of synaptic inhibition, synchronized epileptiform discharges will
develop. |
|
0 |
Traub; Cortical Oscillations |
160 |
|
In the cerebellar cortex, the
only excitatory cells -- the granule cells -- lie in the afferent stream of
mossy fibers, and serve to distribute this stream along the parallel fibers. |
|
0 |
Traub; Cortical Oscillations |
160 |
|
All the cerebellar cortical
neurons, other than granule cells, are inhibitory neurons, and all of the
recurrent synaptic connections are GABAergic. |
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0 |
Traub; Cortical Oscillations |
177 |
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Basic Properties of Single
Neurons and Gap Junctions |
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17 |
Traub; Cortical Oscillations |
179 |
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Cortical Neurons and Their
Models |
|
2 |
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179 |
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The study of the shapes and intrinsic properties of the vastly many types of neurons, and of the synaptic
relations
between neurons, is one of the most beautiful of scientific endeavors. |
|
0 |
Traub; Cortical Oscillations |
179 |
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Gap junctions
-- electrical synaptic connections whose activity appears to underlie a great many persistent
network rhythms. |
|
0 |
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180 |
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Physiological principles governing action potentials -- conventional fast action potentials and many other sorts
of Ca2+-mediated action potentials. |
|
1 |
Traub;
Cortical Oscillations |
180 |
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Membrane
conductances exist that are ion selective; that can produce transmembrane currents that are inward or outward; that have different time courses that can be
characterized by state variables governed by differential equations involving time, membrane potential, and the state
variables themselves; and which can involve multiple states having faster or slower kinetics (i.e. channels that have rapid
activation/deactivation and slower inactivation/recovery). |
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0 |
Traub; Cortical Oscillations |
180 |
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Membrane conductances influence
one another through the common medium of the local membrane potential:
cooperativity exists even at the level of small membrane patches. |
|
0 |
Traub; Cortical Oscillations |
182 |
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By being able to capture much of the intrinsic
electrophysiology of neurons in relatively simple models, it becomes possible to simulate
large networks of neurons on a parallel computer. |
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2 |
Traub; Cortical Oscillations |
182 |
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Simulation
of a population of 15,000
cells, with multiple
functional subclasses, is readily possible. |
|
0 |
Traub; Cortical Oscillations |
182 |
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Simulation of networks of neurons is an essential tool in understanding oscillations. |
|
0 |
Traub; Cortical Oscillations |
182 |
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Firing Patterns of Some Cortical
Interneurons |
|
0 |
Traub; Cortical Oscillations |
182 |
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Two firing patterns that are characteristic of interneurons are fast spiking (FS) and low-threshold spiking (LTS). |
|
0 |
Traub; Cortical Oscillations |
182 |
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Interneurons
may also exhibit regular spiking and bursting. |
|
0 |
Traub; Cortical Oscillations |
182 |
|
Fast spiking (FS)
cells have narrow
spikes, can fire
rapidly,
and have little or no accommodation (i.e. slowing of the frequency with repetitive firing). |
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0 |
Traub; Cortical Oscillations |
182 |
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Low threshold spiking (LTS) cells have somewhat broader spikes, fire an initial burst of spikes when depolarized from a hyperpolarized resting potential, and do not
fire rapidly. |
|
0 |
Traub; Cortical Oscillations |
182 |
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Classification of interneurons is a contentious and intricate subject. |
|
0 |
Traub; Cortical Oscillations |
183 |
|
Firing patterns associated with
some interneurons: Fast Spiking (FS), Low Threshold Spiking (LTS). (diagram) |
|
1 |
Traub; Cortical Oscillations |
185 |
|
Cortical interneurons differ in
the way they respond to oscillation-inducing neuromodulators. |
|
2 |
Traub; Cortical Oscillations |
185 |
|
One of the most effective tools
for studying oscillation in vitro is to apply a neuromodulatory compound to
the bath. The neuromodulator may then be capable of eliciting a network
oscillation that last many hours. |
|
0 |
Traub; Cortical Oscillations |
186 |
|
Differential morphology,
connectivity, firing patterns and sensitivity to neuromodulators in
neocortical interneurons. (diagram) |
|
1 |
Traub; Cortical Oscillations |
187 |
|
Fast Rhythmic Bursting in
Pyramidal Cells |
|
1 |
Traub; Cortical Oscillations |
187 |
|
Two types of firing
pattern that have
been seen in cortical principal neurons are fast rhythmic bursting (FRB), also called "chattering"; and regular
spiking (RS). |
|
0 |
Traub; Cortical Oscillations |
187 |
|
Fast rhythmic bursting (FRB) behavior is unusual; it is found mostly in pyramidal
neurons in superficial layers, but also in pyramidal and non-pyramidal neurons in other cortical layers, and also in the thalamus. |
|
0 |
Traub; Cortical Oscillations |
187 |
|
Regular spiking (RS) is the most common firing pattern seen in cortical pyramidal cells and spiny stellate cells; it is also found in
some interneurons. |
|
0 |
Traub; Cortical Oscillations |
190 |
|
Pyramidal neurons, the most common class of cell
morphology to be found in the cortex, concentrating on the large layer 5 pyramidal cells --
probably the most intensively studied cell type in the brain. |
|
3 |
Traub; Cortical Oscillations |
190 |
|
Intrinsic bursts are especially prominent during epileptiform
events, where they are amplified by recurrent synaptic excitation, and can recur at frequencies as high as 20 Hz or more. |
|
0 |
Traub; Cortical Oscillations |
191 |
|
Regular spiking and intrinsic bursting in pyramidal
neurons of rat visual cortex in vitro. (diagram) |
|
1 |
Traub; Cortical Oscillations |
195 |
|
Strikingly different
patterns of Electrogenesis can occur in the Dendrites vis-ŕ-vis the Soma. |
|
4 |
Traub; Cortical Oscillations |
196 |
|
The firing properties of Axons
are not the same as for Somata. |
|
1 |
Traub; Cortical Oscillations |
196 |
|
Very fast brain
oscillations depend for their generation on physical interactions between axons of principle (excitatory) neurons. Certain gamma and beta oscillations depend on such
interactions as well. |
|
0 |
Traub; Cortical Oscillations |
196 |
|
Both the intrinsic
properties of axons, and the means by which axons communicate with each other, are vital to the generation of oscillations. |
|
0 |
Traub; Cortical Oscillations |
196 |
|
The study of mammalian axons is technically difficult, partly because of their small
size, and partly because of the myelin that ensheaths large portions of many
of them. |
|
0 |
Traub; Cortical Oscillations |
197 |
|
In the late
1940s and early 1950s, Hodgkin and Huxley performed their
classical experiments on, and analysis of, the generation and propagation of action potentials in the isolated squid giant axon. |
|
1 |
Traub; Cortical Oscillations |
197 |
|
Patch clamp recordings, starting in the early 1990s, became possible from the proximal axons of mammalian
pyramidal cells and Purkinje cells. |
|
0 |
Traub; Cortical Oscillations |
197 |
|
Recordings (2003) from single axons of CA3 pyramidal cells showed that
the refractory time
of these axons range
from about 2.5 to about 10 ms. |
|
0 |
Traub; Cortical Oscillations |
198 |
|
The somata of pyramidal cells
can become so depolarized as to be unable to generate action potentials. This
"depolarization block" is presumed to reflect voltage-dependent
inactivation of Na+
channels. |
|
1 |
Traub; Cortical Oscillations |
199 |
|
Under most physiological
conditions, action potentials
are initiated in the proximal axon, in both pyramidal cells and Purkinje cell. |
|
1 |
Traub; Cortical Oscillations |
199 |
|
The axon
initial segment of pyramidal
cells is the site of inhibitory
synapses,
whose presynaptic elements belong to a specialized type of interneuron, the axo-axonic or chandelier cell. |
|
0 |
Traub; Cortical Oscillations |
203 |
|
Many brain
oscillations -- particularly gamma oscillations -- are regulated by GABA-receptor-mediated synaptic inhibition. |
|
4 |
Traub; Cortical Oscillations |
207 |
|
There are differences between
principal neurons and fast spiking interneurons, not only in synaptic
currents and in cell shape, but also in the properties of the intrinsic
membrane conductances, particularly the Na+ and K+ channels that are responsible for action potentials. |
|
4 |
Traub; Cortical Oscillations |
207 |
|
Bath application of kainate
constitutes a particularly robust method for the induction
of oscillations in cortical
circuits, when used in concentrations of 1 µM or
less. |
|
0 |
Traub; Cortical Oscillations |
207 |
|
NMDA and AMPA glutamate
receptors are constituted of different types of subunits, with receptor
properties depending on which types of subunits have co-assembled. |
|
0 |
Traub; Cortical Oscillations |
212 |
|
Gap Junctions and the Notion of
Electrical Coupling between Axons |
|
5 |
Traub; Cortical Oscillations |
212 |
|
Many brain oscillations depend
on gap junctions, which can
be visualized as a collection of small tunnels between cell interiors. |
|
0 |
Traub; Cortical Oscillations |
212 |
|
Gap junctions
between principal neurons include pyramidal neurons,
hippocampal dentate cells, and cerebellar Purkinje cells. |
|
0 |
Traub; Cortical Oscillations |
213 |
|
Chemical synapses do not make the the whole story of network
connectivity,
and a rather small number of strategically placed gap junctions can have striking and profound effects on network activities. |
|
1 |
Traub; Cortical Oscillations |
213 |
|
Junctions are confined to
multicelled animals. They occur in extremely primitive animals, including
coral animals, jellyfish, and sea anemones. They do not occur in plants,
bacteria, or protozoa. |
|
0 |
Traub; Cortical Oscillations |
214 |
|
Gap junctions
occur very early in
development and are crucial for the embryo to develop properly. |
|
1 |
Traub; Cortical Oscillations |
214 |
|
Gap junctions in the heart are
crucial to life; it is through them that cardiac action potential can conduct
from myocyte to myocyte, so that an organized pattern of muscle contraction
(and effective cardiac pumping) is possible. |
|
0 |
Traub; Cortical Oscillations |
214 |
|
Gap junctions
are present between nerve cells, where they allow
for a type of neuron-neuron signaling that compliments chemical synapses. |
|
0 |
Traub; Cortical Oscillations |
214 |
|
Gap junction channels have an aqueous interior through which ionic currents can flow -- the physical basis of electronic coupling between pairs of cells. |
|
0 |
Traub; Cortical Oscillations |
214 |
|
In addition to ionic currents, other molecular species (generally of molecular weight up to ~1000) can also pass
through the gap junction channel. |
|
0 |
Traub; Cortical Oscillations |
215 |
|
The term "gap
junction" refers to an assembly of contiguous, packed, gap
junction channels, anywhere from just
a few of them to many
thousands. |
|
1 |
Traub; Cortical Oscillations |
215 |
|
Gap junction channels are likely to be packed tightly
together,
most often into a hexagonal array. |
|
0 |
Traub; Cortical Oscillations |
215 |
|
The gap
junction assembly as a whole will have a characteristic shape, usually a disk or plaque, but possibly a ribbon or a network like (reticular) structure. |
|
0 |
Traub; Cortical Oscillations |
215 |
|
There may be yet another level
of scaling, as pairs of cells may be connected by several gap junctions. |
|
0 |
Traub; Cortical Oscillations |
217 |
|
Structure of a Gap Junction
Channel |
|
2 |
Traub; Cortical Oscillations |
217 |
|
High resolution x-ray crystallography would, in
principle, provide structural data useful in understanding the biophysics of gap junction channels. However, most membrane proteins are unstable in solution, and do not lend themselves to crystallization. |
|
0 |
Traub; Cortical Oscillations |
217 |
|
Electron crystallographic
structure of a recombinant cardiac gap junction. (diagram) |
|
0 |
Traub; Cortical Oscillations |
217 |
|
Adult mammalian brain regions
and cell types for which gap junctions have been reported include the retina,
basal ganglia, cerebral cortex, hippocampus, nucleus reticularis thalami,
thalamocortical relay cells, inferior olive, and interneurons in the molecular
layer of the cerebellum. |
|
0 |
Traub; Cortical Oscillations |
217 |
|
Cells of
the inferior olive (a
medullary structure)
give rise to the cerebellar climbing fibers. |
|
0 |
Traub; Cortical Oscillations |
220 |
|
Gap Junctions and Interneuron
Network Oscillations |
|
3 |
Traub; Cortical Oscillations |
220 |
|
There are a number of experimental oscillation models, at theta to gamma frequencies, in which pharmacologically isolated
populations as GABAergic
neurons generate network
oscillations. |
|
0 |
Traub; Cortical Oscillations |
220 |
|
Hippocampal
and neocortical
interneuron
network oscillation requires mutual GABAergic synaptic inhibition. |
|
0 |
Traub; Cortical Oscillations |
227 |
|
Dye
coupling was described between principled cells in hippocampus and neocortex, beginning almost 30 years ago (1982). |
|
7 |
Traub; Cortical Oscillations |
227 |
|
The so-called percolation limit (in which one cell couples to one other, on average), the limit at which collective behavior becomes
possible. |
|
0 |
Traub; Cortical Oscillations |
227 |
|
One cell coupled
to 2.25 others, on average, well above the percolation
limit --
but still well below the density of recurrent excitatory synaptic connections
in CA1. |
|
0 |
Traub; Cortical Oscillations |
243 |
|
In Vitro Oscillations |
|
16 |
Traub; Cortical Oscillations |
245 |
|
Very Fast Oscillations (VFO) |
|
2 |
Traub; Cortical Oscillations |
245 |
|
Consider mechanisms of very fast
oscillations (VFO, faster than approximately 70 Hz) in telencephalic cortical
structures (e.g. hippocampus, neocortex, and entorhinal cortex) and in
cerebellar cortex. |
|
0 |
Traub; Cortical Oscillations |
245 |
|
VFO
requires gap junctions, connecting the axons of principal neurons. |
|
0 |
Traub; Cortical Oscillations |
245 |
|
VFO can be
generated without
chemical synapses (in particular, without
GABAA receptors), and even seem to be enhanced by the blockade of chemical synapses. |
|
0 |
Traub; Cortical Oscillations |
245 |
|
With chemical synapses imtact,
both telencephalic and cerebellar cortex happily coexist with either lower
frequency oscillations, or with transient synchronized discharges such a
sharp waves. |
|
0 |
Traub; Cortical Oscillations |
245 |
|
VFO cannot be
understood as arising
from a system of coupled oscillators. |
|
0 |
Traub; Cortical Oscillations |
245 |
|
Telencephalic cortical VFO can
be accounted for with a model in which electrical
coupling is functionally
strong,
so that a spike
in one axon may be able to evoke a spike in a coupled axon. |
|
0 |
Traub; Cortical Oscillations |
245 |
|
Cerebellar VFO can be accounted
for with a model in which the coupling is relatively weak, so that only when
multiple near-simultaneous spikes occur, in axons coupled to a selected axon,
will the selected axon itself fire. |
|
0 |
Traub; Cortical Oscillations |
245 |
|
VFO In reasonably physiological
conditions in vivo can occur spontaneously, superimposed on physiological
sharp waves in the hippocampus and deep entorhinal cortex, and during the
depolarizing phase of the slow oscillation; or it can be superimposed on cortical
evoked responses that follow brief sensory inputs, in somatosensory and
auditory modalities. |
|
0 |
Traub; Cortical Oscillations |
246 |
|
In all the cases of VFO oscillations, populations of cortical neurons become transiently
depolarized. |
|
1 |
Traub; Cortical Oscillations |
246 |
|
VFO in nonepileptic conditions
can occur superimposed on spontaneous (or also evoked) sharp waves. |
|
0 |
Traub; Cortical Oscillations |
246 |
|
It is possible to produce VFO
without gamma or beta-2, but it is not clear if the reverse is true, at least
for persistent rhythms. |
|
0 |
Traub; Cortical Oscillations |
246 |
|
VFO can occur a leading into an
interictal burst or seizure, or superimposed upon burst complexes without a
seizure. |
|
0 |
Traub; Cortical Oscillations |
246 |
|
VFO can also occur in isolation
in epilepticogenic tissue, especially at frequencies above 250 or 300 Hz
(so-called "fast ripples"). |
|
0 |
Traub; Cortical Oscillations |
246 |
|
Fast ripples can be generated in
very small volumes of tissue, about 1 mm3. |
|
0 |
Traub; Cortical Oscillations |
246 |
|
Associated with epileptogenesis,
VFO cannot occur leading in into an interictal burst or seizure; superimposed
on synchronized bursts; or between bursts complexes. |
|
0 |
Traub; Cortical Oscillations |
246 |
|
Generation of VFO Does Not
Require GABAergic Interneurons |
|
0 |
Traub; Cortical Oscillations |
247 |
|
When ripple oscillations were
first discovered in the hippocampus (Buzsáki et al., 1992), it was
immediately realized that interneurons could fire at the frequency of the
ripple (~200 Hz), but that pyramidal cells -- at least the somata -- did not;
and indeed, many pyramidal cell somata seemed not to fire at all. |
|
1 |
Traub; Cortical Oscillations |
247 |
|
Although it seemed natural to
postulate that networks of fast-spiking interneurons generate the ripple
oscillations, there are several reasons for rejecting this idea. |
|
0 |
Traub; Cortical Oscillations |
247 |
|
There are many
examples of VFO occurring with chemical synaptic transmission completely
blocked. |
|
0 |
Traub; Cortical Oscillations |
247 |
|
Somatic spiking is not the
proper measure of pyramidal cell activity, as there is evidence for an
antidromic (i.e. axonal) origin of spikes during VFO. |
|
0 |
Traub; Cortical Oscillations |
248 |
|
A network of pyramidal
cells axons that are electrically
coupled can generate population
VFO. |
|
1 |
Traub; Cortical Oscillations |
248 |
|
Because AMPA receptor-mediated excitatory postsynaptic conductances (EPSCs) and fast spiking (FS) interneurons are so extremely rapid (decay time of order of 1 ms), the output of an oscillating
pyramidal cell axon plexus can synaptically
impose a coherent VFO
in a population of FS
cells -- and the FS cells, in turn, can impose coherent compound IPSPs on the pyramidal cells. |
|
0 |
Traub; Cortical Oscillations |
249 |
|
A pyramidal
cell axonal plexus can generate
population VFO provided: (1) electrical
coupling is present, (2) the axons are sufficiently excitable, and (3) there is at
least some degree of spontaneous activity. |
|
1 |
Traub; Cortical Oscillations |
249 |
|
Nonsynaptic VFO occurs in other
brain regions besides hippocampal pyramidal cell regions. |
|
0 |
Traub; Cortical Oscillations |
249 |
|
The somatic firing rate can be
much lower than the population oscillation frequency, but each population
wave is accompanied either by a full spike, or by a spikelet in a given
neuron. |
|
0 |
Traub; Cortical Oscillations |
250 |
|
VFO occurs without chemical synapses, but requires gap junctions. |
|
1 |
Traub; Cortical Oscillations |
250 |
|
Full somatic action potentials,
in any given neuron, do not follow that population frequency. |
|
0 |
Traub; Cortical Oscillations |
251 |
|
The gap
junctional coupling between
pyramidal cells is extremely
sparse,
with each cell
(at least in hippocampal CA1) coupled to approximately 2 others. |
|
1 |
Traub; Cortical Oscillations |
251 |
|
VFO can be coherent over
distances greater than 300 µ in CA1, i.e. it is coherent across population of
hundreds, or thousands, of neurons, despite the extremely low gap junctional
connectivity. |
|
0 |
Traub; Cortical Oscillations |
251 |
|
The most economical hypothesis
for the experimental observations is to suppose that coupled axons generate
VFO. |
|
0 |
Traub; Cortical Oscillations |
252 |
|
We would not expect electrically
coupled axons to behave as phase coupled oscillators, because of the extreme
nonlinearity of the axonal membrane (due to the presence of either a high
density, or low for threshold, or both for Na+ channels). |
|
1 |
Traub; Cortical Oscillations |
252 |
|
Simulated a large network of axonally coupled neurons at low
coupling densities. |
|
0 |
Traub; Cortical Oscillations |
252 |
|
Axonally coupled networks can produce VFO with sparse coupling under quite general conditions: |
|
0 |
Traub; Cortical Oscillations |
252 |
|
Condition (1), Axonally coupled
networks can produce VFO when the density of connections (i.e. gap junctions)
was higher than one gap junction per axon, on average, the so-called
percolation limit; but the density was not so high that all the axons started
to fire at maximal frequency. |
|
0 |
Traub; Cortical Oscillations |
252 |
|
In an earlier study, the average
density was kept below three or four gap junctions per axon. |
|
0 |
Traub; Cortical Oscillations |
252 |
|
Condition (2), Axonally coupled
networks can produce VFO when the conductance of a gap junction (or
junctions) between a coupled pair of axons was large enough that an action
potential in one axon could induce an action potential in the other (provided
the other is not absolutely refractory). |
|
0 |
Traub; Cortical Oscillations |
252 |
|
The minimum value of the gap
junction conductance will depend on the intrinsic membrane properties, and on
how far the gap junction is from the soma. |
|
0 |
Traub; Cortical Oscillations |
252 |
|
Condition (3), Axonally coupled
networks can produce VFO when there is a source of background spontaneous
action potentials, so-called atopic spikes. The frequency of ectopic spikes
could be very low (e.g. 0.05 Hz per axon), but not zero. |
|
0 |
Traub; Cortical Oscillations |
253 |
|
Graph theory
has developed into a rich branch of mathematics;
a collection of vertices, or nodes, along with the collection of edges, each edge connects a pair of vertices. |
|
1 |
Traub; Cortical Oscillations |
254 |
|
How long are the paths between different vertices? Waves of
activity will begin with spontaneous spikes that spread along the edges, or gap
junctions,
and the period will be determined by how
many edges must be crossed (on average) to reach a majority of the population. |
|
1 |
Traub; Cortical Oscillations |
254 |
|
Percolation limit -- If parameter c is less than 0.5, then each vertex connects to less than one other vertex on
average. |
|
0 |
Traub; Cortical Oscillations |
256 |
|
Structural Properties of Large
Random Graphs (diagram) |
|
2 |
Traub; Cortical Oscillations |
256 |
|
Parameter c is the ratio of the number of edges to the number
of nodes (or vertices). |
|
0 |
Traub; Cortical Oscillations |
256 |
|
Parameter c is equal to one half
the mean index, the average number of edges emanating from each node. |
|
0 |
Traub; Cortical Oscillations |
260 |
|
Shunting by gap junctions. In a random graph, the statistical distribution of the number of edges on a vertex is Poisson. In a large
random graphs, there will always be a few vertices with a large
number of edges. |
|
4 |
Traub; Cortical Oscillations |
260 |
|
An axonal plexus with random topology will lead to the
existence of a few axons that are gap-junctionally
connected to many
other axons. |
|
0 |
Traub; Cortical Oscillations |
260 |
|
A large
number of gap
junctions will act as a shunt, so that if one
axon fires, its spike may not be communicated. |
|
0 |
Traub; Cortical Oscillations |
260 |
|
Random graphs
that are sufficiently large contain reentry cycles of any given order (length). |
|
0 |
Traub; Cortical Oscillations |
260 |
|
Very fast oscillations (VFO)
can occur nested with
a slower oscillation, beta-2 (20-30
Hz). |
|
0 |
Traub; Cortical Oscillations |
260 |
|
Slower membrane currents and
synaptic currents break VFO up into packets. |
|
0 |
Traub; Cortical Oscillations |
260 |
|
Beta-2 oscillation exists with
intact chemical synaptic transmission, but does not depend on it. |
|
0 |
Traub; Cortical Oscillations |
260 |
|
Beta-2 oscillation does depend
on gap junctions. |
|
0 |
Traub; Cortical Oscillations |
261 |
|
VFO and beta-2 oscillation can
coexist, one nested on the other. |
|
1 |
Traub; Cortical Oscillations |
261 |
|
The data suggest that an axonal,
and perisomatic, phasic hyperpolarizing current can serve to break VFO into
short epochs, separated by a longer epochs. The duration of the longer epochs
is determined by the kinetics of the hyperpolarizing process. |
|
0 |
Traub; Cortical Oscillations |
262 |
|
VFO also
occurs nested with persistent hippocampal and medial entorhinal gamma oscillations. |
|
1 |
Traub; Cortical Oscillations |
262 |
|
Persistent gamma oscillations require both gap junctions and chemical synapses, specifically, AMPA receptors and GABAA receptors. |
|
0 |
Traub; Cortical Oscillations |
262 |
|
The data suggest that synaptic inhibition in perisomatic regions is acting to break VFO into short segments -- an effect that
will be possible if axonal
gap junctions are not
located too distant from the soma and
initial segment. |
|
0 |
Traub; Cortical Oscillations |
262 |
|
VFO is coherent over distances of at
least 300 µ, so that hundreds of cells (at least) must
be participating. |
|
0 |
Traub; Cortical Oscillations |
262 |
|
VFO in the hippocampus, neocortex, and other telencephalic structures arises because of relatively rare spontaneous action potentials, percolating from axon to axon across gap junctions, with period determined by the global topological network
structure, rather than by intrinsic membrane or synaptic conductances. |
|
0 |
Traub; Cortical Oscillations |
269 |
|
Beta-2 Oscillations |
|
7 |
Traub; Cortical Oscillations |
269 |
|
Beta oscillations (10-30 Hz) can occur during the slow oscillation of sleep, during the memory
phase of a cognitive
task (typically associated with behavioral immobility), and in the course of auditory evoked potentials. |
|
0 |
Traub; Cortical Oscillations |
269 |
|
Beta oscillations can occur during status
epilepticus. |
|
0 |
Traub; Cortical Oscillations |
269 |
|
Enhanced beta activity occurs in Parkinsonian syndromes. |
|
0 |
Traub; Cortical Oscillations |
269 |
|
Decreased
beta frequency phase synchrony, of cortical oscillations, has been demonstrated in schizophrenia. |
|
0 |
Traub; Cortical Oscillations |
269 |
|
There are many
other observations of beta
oscillations occurring in the cortex during sensory stimulation and cognitive tasks. |
|
0 |
Traub; Cortical Oscillations |
269 |
|
Beta-2 oscillations (20-30 Hz) can be nested with very fast oscillations (VFO). |
|
0 |
Traub; Cortical Oscillations |
270 |
|
In secondary
somatosensory cortex, gamma
oscillations are generated in superficial layers, and beta-2 in deep layers. |
|
1 |
Traub; Cortical Oscillations |
270 |
|
Intracellular recordings have
shown that it is intrinsically bursting pyramidal cells that robustly participate in the beta-2
oscillation. |
|
0 |
Traub; Cortical Oscillations |
270 |
|
Cell may have voltage
fluctuations at a time lock to a population oscillation, and yet the somata
fire at much lower rates than the population frequency. |
|
0 |
Traub; Cortical Oscillations |
270 |
|
Somata firing at much lower
rates than the population frequency occurs in the inferior olive. |
|
0 |
Traub; Cortical Oscillations |
271 |
|
Somatosensory cortex beta-2
oscillation requires gap junctions. |
|
1 |
Traub; Cortical Oscillations |
271 |
|
The beta-2 oscillation, as a
population phenomenon, cannot be understood as a system of coupled cellular
oscillators. |
|
0 |
Traub; Cortical Oscillations |
274 |
|
Not only are gap junctions
required for beta-2, but chemical synapses appear not to be required, at
least not beyond providing tonic excitation to the network. |
|
3 |
Traub; Cortical Oscillations |
276 |
|
Somatosensory cortex beta-2
appears to be an exclusively gap junction mediated type of oscillation. |
|
2 |
Traub; Cortical Oscillations |
276 |
|
Beta-2 isolation can occur in
nested with VFO. |
|
0 |
Traub; Cortical Oscillations |
276 |
|
Beta-2 oscillations have been
observed in primary motor cortex, M1. These oscillations have several
properties in common with somatosensory cortex beta-2. |
|
0 |
Traub; Cortical Oscillations |
276 |
|
Analysis of phase delays
indicates that M1 beta-2 oscillation originates in deep layers. |
|
0 |
Traub; Cortical Oscillations |
276 |
|
Unlike somatosensory cortex, M1
cortex does not exhibit gamma oscillation in the superficial layers. |
|
0 |
Traub; Cortical Oscillations |
280 |
|
There are multiple forms of beta
rhythm in the cortex, and most have close associations with prior or ongoing
gamma rhythms. |
|
4 |
Traub; Cortical Oscillations |
280 |
|
More and more frequency bands
within the EEG range are discovered to have a clearly defined and distinct
mechanisms. |
|
0 |
Traub; Cortical Oscillations |
280 |
|
Robust existence of gamma and
beta-2 rhythms provides an ideal starting point to address the issue of
multiple coexistent frequency bands. |
|
0 |
Traub; Cortical Oscillations |
280 |
|
The pattern of temporal
interactions between deep and superficial layers of the cortex generate
beta-2 and temporal gamma frequency oscillations. |
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0 |
Traub; Cortical Oscillations |
280 |
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With strong excitation of
somatosensory cortex, the beta-2 and gamma rhythms have no stable phase
relationship, suggesting that the beta-2 rhythm is operating to disconnect
the main input areas in a cortical column (layer 4 and above) from the
primary descending output layer (layer 5). |
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0 |
Traub; Cortical Oscillations |
281 |
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Once the excitation of cortex is
reduced, both the beta-2 and gamma periods are present in individual neurons,
but they are organized such that one gamma period is followed by one beta-2
period, repeatedly. |
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1 |
Traub; Cortical Oscillations |
281 |
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The population rhythm is
manifest as if sum of these two original periods -- resulting in a slower
beta-1 frequency rhythm. |
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0 |
Traub; Cortical Oscillations |
281 |
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Theoretically, interactions
between co-express frequencies may occur throughout the dynamic range of the
EEG, placing gap junction-mediated network phenomena at the very heart of
cortical dynamics. |
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0 |
Traub; Cortical Oscillations |
282 |
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Persistent Gamma Oscillations |
|
1 |
Traub; Cortical Oscillations |
289 |
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Persistent Gamma
Oscillation Requires Gap
Junctions |
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7 |
Traub; Cortical Oscillations |
289 |
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The gap junctions required for
persistent gamma oscillations are those between primary cells. |
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0 |
Traub; Cortical Oscillations |
289 |
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Electrical coupling has been found to be a extremely
rare between interneurons. |
|
0 |
Traub; Cortical Oscillations |
291 |
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During persistent gamma
oscillation, pyramidal cell firing is sparse, but (on average) leads the
firing of fast-spiking interneurons by a few milliseconds. |
|
2 |
Traub; Cortical Oscillations |
293 |
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Interneuron gap junctions
modulate the power of persistent gamma oscillations. |
|
2 |
Traub; Cortical Oscillations |
295 |
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GABAA receptors can excite the pyramidal cell axonal plexus to
generate VFO. |
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2 |
Traub; Cortical Oscillations |
295 |
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IPSPs repeatedly interrupt VFO,
to generate persistent gamma oscillations. |
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0 |
Traub; Cortical Oscillations |
298 |
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Fast rhythmic bursting (FRB)
cells (chattering cells) are necessary for persistent gamma oscillation in
superficial layers of auditory cortex. |
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3 |
Traub; Cortical Oscillations |
301 |
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Action potentials during
persistent gamma oscillations are predicted to be antidromic. |
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3 |
Traub; Cortical Oscillations |
302 |
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Epileptiform Discharges In Vitro |
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1 |
Traub; Cortical Oscillations |
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