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Impaired synaptic plasticity in the surround of perinatally acquired dysplasia in rat cerebral cortex

Item Type:Article
Title:Impaired synaptic plasticity in the surround of perinatally acquired dysplasia in rat cerebral cortex
Creators Name:Peters, O. and Redecker, C. and Hagemann, G. and Bruehl, C. and Luhmann, H.J. and Witte, O.W.
Abstract:Freeze-lesion induced neocortical dysplasias in rats mimic numerous aspects of human polymicrogyria and are used as a model for the study of developmental migration disorders. Since memory tests have demonstrated learning deficits in rodents with neocortical malformations, we investigated the expression and properties of long-term potentiation (LTP) in neocortical slices from adult freeze-lesioned and control rats. Field potentials, recorded in layer II/III at a distance of 2-3 mm lateral to perinatally induced microgyri, were strongly enhanced following theta-burst stimulation in layer VI (amplitude: 174 +/- 4%) compared to controls (110 +/- 2%). In contrast, in layer IV of the freeze-lesioned cortex LTP could not reliably be induced. Histochemical analysis, performed to elucidate the cellular basis of the impaired plasticity, revealed diminished amounts of the GABAA-receptor subunit gamma2 in the paramicrogyral zone, likely representing a diminished GABA-ergic filter, which is thought to prevent LTP induced in layer VI under normal conditions. Cytochrome-oxidase staining after electrophysiological examination disclosed that LTP in layer IV of the freeze-lesioned cortex could only be elicited, when stimulation was applied within a preserved barrel cortex. Our study provides evidence that focal cryolesions during cortical development cause an impaired synaptic plasticity that may underlie learning disabilities.
Keywords:Developmental Migration Disorder, Learning Disabilities, Long-Term Potentiation, Neocortical Malformation, Polymicrogyria, Animals, Rats, Wistar Rats
Source:Cerebral Cortex
ISSN:1047-3211
Publisher:Oxford Univ Press Inc (U.S.A.)
Volume:14
Number:10
Page Range:1081-1087
Date:October 2004
Official Publication:https://doi.org/10.1093/cercor/bhh067
PubMed:View item in PubMed

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