Document Detail

Feedforward inhibition contributes to the control of epileptiform propagation speed.
MedLine Citation:
PMID:  17392454     Owner:  NLM     Status:  MEDLINE    
It is still poorly understood how epileptiform events can recruit cortical circuits. Moreover, the speed of propagation of epileptiform discharges in vivo and in vitro can vary over several orders of magnitude (0.1-100 mm/s), a range difficult to explain by a single mechanism. We previously showed how epileptiform spread in neocortical slices is opposed by a powerful feedforward inhibition ahead of the ictal wave. When this feedforward inhibition is intact, epileptiform spreads very slowly (approximately 100 microm/s). We now investigate whether changes in this inhibitory restraint can also explain much faster propagation velocities. We made use of a very characteristic pattern of evolution of ictal activity in the zero magnesium (0 Mg2+) model of epilepsy. With each successive ictal event, the number of preictal inhibitory barrages dropped, and in parallel with this change, the propagation velocity increased. There was a highly significant correlation (p < 0.001) between the two measures over a 1000-fold range of velocities, indicating that feedforward inhibition was the prime determinant of the speed of epileptiform propagation. We propose that the speed of propagation is set by the extent of the recruitment steps, which in turn is set by how successfully the feedforward inhibitory restraint contains the excitatory drive. Thus, a single mechanism could account for the wide range of propagation velocities of epileptiform events observed in vitro and in vivo.
Andrew J Trevelyan; David Sussillo; Rafael Yuste
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Publication Detail:
Type:  In Vitro; Journal Article; Research Support, N.I.H., Extramural; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  The Journal of neuroscience : the official journal of the Society for Neuroscience     Volume:  27     ISSN:  1529-2401     ISO Abbreviation:  J. Neurosci.     Publication Date:  2007 Mar 
Date Detail:
Created Date:  2007-03-29     Completed Date:  2007-04-24     Revised Date:  2010-06-18    
Medline Journal Info:
Nlm Unique ID:  8102140     Medline TA:  J Neurosci     Country:  United States    
Other Details:
Languages:  eng     Pagination:  3383-7     Citation Subset:  IM    
Department of Biological Sciences, Howard Hughes Medical Institute, Columbia University, New York, New York 10027, USA.
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MeSH Terms
Brain Mapping
Cerebral Cortex / pathology,  physiopathology*
Epilepsy / diagnosis,  physiopathology*
Feedback, Physiological
Mice, Inbred C57BL
Microscopy, Confocal
Patch-Clamp Techniques
Pyramidal Cells / physiopathology*
Grant Support
Comment In:
Epilepsy Curr. 2007 Sep-Oct;7(5):138-9   [PMID:  17998976 ]

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