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Title:Functional implications of behavioral experience effects upon the rat visual cortex
Author(s):Wang, Xinbo
Doctoral Committee Chair(s):Greenough, William T.
Department / Program:Neuroscience
Degree Granting Institution:University of Illinois at Urbana-Champaign
Subject(s):Biology, Neuroscience
Biology, Animal Physiology
Psychology, Physiological
Abstract:In layer II/III of the visual cortex, synaptic transmission at the level of the field evoked response, which included a population spike (PS), a field excitatory postsynaptic potential (fEPSP) and slow components, was characterized in response to the stimulation of lateral white matter. The PS of the field evoked response showed long-term potentiation (LTP), following low frequency tetanization, with two expression patterns, one possibly mediated by voltage dependent calcium channels (VDCCs) and the other by VDCCs and N-methyl-D-aspartate (NMDA) glutamate receptors. In search for functional implications of behavioral experience effects upon neocortex, field evoked responses in the rat visual cortex were examined following complex environment (EC) and individual cage (IC) rearing. The results showed "behavioral LTP" (Greater PS amplitude) elicited after 7 and 30 days of exposure in EC animals compared to IC littermates. The persistence of this "behavioral LTP" was dependent on continued exposure to the EC experience. In comparison with anatomical results, 30 day "behavioral LTP" may involve increased numbers of synapses per neuron with stable synaptic density, whereas 7 day "behavioral LTP" may engage pre-existing synapse modification as well as increased synapse density. "Behavioral LTP" disappeared in the absence of EC rearing. "Behavioral LTP" was not observed in the absence of EC rearing. The temporary nature of "behavioral LTP" contrasted with persisting dendritic effects on EC vs. IC rat visual cortex. Cellularly, "behavioral LTP" induced following long-term differential rearing may share common mechanisms with electrical LTP. Electrical LTP production in terms of the percentage of PS alterations in the visual cortex was reduced in 30 day EC rats compared to their IC littermates. MK-801 sensitive NMDA glutamate receptor-mediated EPSPs (NMDA EPSPs), which were involved in cortical LTP production, were significantly larger in the EC rat visual cortex than in the IC. This indicated that cellular mechanisms that mediate electrical LTP may also underlie "behavioral LTP". Thus, the results suggest that behavioral experience elicits functional alterations reflecting anatomical changes in the neocortex and support the notion that processes participating in LTP production may also be involved in functional changes following behavioral experience.
Issue Date:1994
Rights Information:Copyright 1994 Wang, Xinbo
Date Available in IDEALS:2011-05-07
Identifier in Online Catalog:AAI9503346
OCLC Identifier:(UMI)AAI9503346

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