Document Detail

Altered intrinsic properties of neuronal subtypes in malformed epileptogenic cortex.
MedLine Citation:
PMID:  21167139     Owner:  NLM     Status:  MEDLINE    
Neuronal intrinsic properties control action potential firing rates and serve to define particular neuronal subtypes. Changes in intrinsic properties have previously been shown to contribute to hyperexcitability in a number of epilepsy models. Here we examined whether a developmental insult producing the cortical malformation of microgyria altered the identity or firing properties of layer V pyramidal neurons and two interneuron subtypes. Trains of action potentials were elicited with a series of current injection steps during whole cell patch clamp recordings. Cells in malformed cortex identified as having an apical dendrite had firing patterns similar to control pyramidal neurons. The duration of the second action potential in the train was increased in paramicrogyral (PMG) pyramidal cells, suggesting that these cells may be in an immature state, as was previously found for layer II/III pyramidal neurons. Based on stereotypical firing patterns and other intrinsic properties, fast-spiking (FS) and low threshold-spiking (LTS) interneuron subpopulations were clearly identified in both control and malformed cortex. Most intrinsic properties measured in malformed cortex were unchanged, suggesting that subtype identity is maintained. However, LTS interneurons in lesioned cortex had increased maximum firing frequency, decreased initial afterhyperpolarization duration, and increased total adaptation ratio compared to control LTS cells. FS interneurons demonstrated decreased maximum firing frequencies in malformed cortex compared to control FS cells. These changes may increase the efficacy of LTS while decreasing the effectiveness of FS interneurons. These data indicate that differential alterations of individual neuronal subpopulations may endow them with specific characteristics that promote epileptogenesis.
Amanda L George; Kimberle M Jacobs
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Publication Detail:
Type:  Comparative Study; Journal Article; Research Support, N.I.H., Extramural; Research Support, Non-U.S. Gov't     Date:  2010-12-15
Journal Detail:
Title:  Brain research     Volume:  1374     ISSN:  1872-6240     ISO Abbreviation:  Brain Res.     Publication Date:  2011 Feb 
Date Detail:
Created Date:  2011-01-31     Completed Date:  2011-12-12     Revised Date:  2014-09-20    
Medline Journal Info:
Nlm Unique ID:  0045503     Medline TA:  Brain Res     Country:  Netherlands    
Other Details:
Languages:  eng     Pagination:  116-28     Citation Subset:  IM    
Copyright Information:
Copyright © 2010 Elsevier B.V. All rights reserved.
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MeSH Terms
Action Potentials / physiology*
Animals, Newborn
Pyramidal Cells / abnormalities*,  physiology*,  physiopathology
Somatosensory Cortex / abnormalities*,  physiology*,  physiopathology
Grant Support
NS054210/NS/NINDS NIH HHS; R01 NS054210/NS/NINDS NIH HHS; R01 NS054210-01A2/NS/NINDS NIH HHS; R01 NS054210-02/NS/NINDS NIH HHS; R01 NS054210-03/NS/NINDS NIH HHS

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