Document Detail


Characterization of synaptic conductances and integrative properties during electrically induced EEG-activated states in neocortical neurons in vivo.
MedLine Citation:
PMID:  16014785     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
The activation of the electroencephalogram (EEG) is paralleled with an increase in the firing rate of cortical neurons, but little is known concerning the conductance state of their membrane and its impact on their integrative properties. Here, we combined in vivo intracellular recordings with computational models to investigate EEG-activated states induced by stimulation of the brain stem ascending arousal system. Electrical stimulation of the pedonculopontine tegmental (PPT) nucleus produced long-lasting (approximately 20 s) periods of desynchronized EEG activity similar to the EEG of awake animals. Intracellularly, PPT stimulation locked the membrane into a depolarized state, similar to the up-states seen during deep anesthesia. During these EEG-activated states, however, the input resistance was higher than that during up-states. Conductance measurements were performed using different methods, which all indicate that EEG-activated states were associated with a synaptic activity dominated by inhibitory conductances. These results were confirmed by computational models of reconstructed pyramidal neurons constrained by the corresponding intracellular recordings. These models indicate that, during EEG-activated states, neocortical neurons are in a high-conductance state consistent with a stochastic integrative mode. The amplitude and timing of somatic excitatory postsynaptic potentials were nearly independent of the position of the synapses in dendrites, suggesting that EEG-activated states are compatible with coding paradigms involving the precise timing of synaptic events.
Authors:
Michael Rudolph; Joe Guillaume Pelletier; Denis Paré; Alain Destexhe
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Publication Detail:
Type:  Comparative Study; Journal Article; Research Support, N.I.H., Extramural; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, P.H.S.     Date:  2005-07-13
Journal Detail:
Title:  Journal of neurophysiology     Volume:  94     ISSN:  0022-3077     ISO Abbreviation:  J. Neurophysiol.     Publication Date:  2005 Oct 
Date Detail:
Created Date:  2005-09-14     Completed Date:  2005-12-30     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  0375404     Medline TA:  J Neurophysiol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  2805-21     Citation Subset:  IM    
Affiliation:
Unité de Neuroscience Intégratives et Computationnelles, Centre National de la Recherche Scientifique, Gif-sur-Yvette, France.
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MeSH Terms
Descriptor/Qualifier:
Animals
Cats
Dose-Response Relationship, Radiation
Electric Conductivity
Electric Stimulation*
Electroencephalography / radiation effects*
Membrane Potentials / physiology,  radiation effects
Models, Neurological
Neocortex / cytology*
Neural Inhibition / physiology,  radiation effects
Neurons / radiation effects*
Normal Distribution
Potassium / metabolism
Spectrum Analysis / methods
Synaptic Transmission / radiation effects*
Time Factors
alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid / metabolism
gamma-Aminobutyric Acid / metabolism
Chemical
Reg. No./Substance:
56-12-2/gamma-Aminobutyric Acid; 7440-09-7/Potassium; 77521-29-0/alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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