Selective Modification of Short-Term Hippocampal Synaptic Plasticity and Impaired Memory Extinction in Mice with a Congenitally Reduced Hippocampal Commissure
- UNCG Author/Contributor (non-UNCG co-authors, if there are any, appear on document)
- Douglas Wahlsten, Visiting Professor (Creator)
- Institution
- The University of North Carolina at Greensboro (UNCG )
- Web Site: http://library.uncg.edu/
Abstract: The hippocampus is critical for forming new long-term memories,
but the contributions of the hippocampal commissure (HC)
to memory function and hippocampal synaptic plasticity are
unclear. To shed light on this issue, we characterized behavioral
memory and hippocampal synaptic plasticity in two inbred
mouse strains. BALB/cWah1 mice display a range of corpus
callosal defects and an intact HC, whereas 9XCA/Wah mice
exhibit a complete absence of corpus callosum and a greatly
reduced HC. No differences between strains were found in
long-term potentiation (LTP) within two synaptic pathways in
hippocampal slices. However, paired-pulse facilitation was deficient
in area CA1 of slices from 9XCA/Wah, and it was rescued
by decreasing extracellular [Ca2+], suggesting that presynaptic
calcium dynamics may be altered in this strain. In addition,
contextual fear extinction was impaired in 9XCA/Wah mice, but
performance on cued fear extinction and on 24 hr memory tests
for cued and contextual fear conditioning were not significantly
different between strains. Thus, an intact HC is critical for
normal extinction of contextual fear. Intact interhemispheric
connectivity is not required for acquisition or expression of
cued and contextual fear conditioning. LTP was normal in slices
from mice that lacked an intact HC, and this was correlated with
normal performance on fear conditioning tests. In contrast,
impaired short-term synaptic plasticity was correlated with defective
contextual memory extinction in mice lacking an intact
HC. Thus, the HC in mice is vital for particular aspects of
memory function and for short-term synaptic modification in
specific hippocampal circuits.
Selective Modification of Short-Term Hippocampal Synaptic Plasticity and Impaired Memory Extinction in Mice with a Congenitally Reduced Hippocampal Commissure
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Additional Information
- Publication
- The Journal of Neuroscience, September 15, 2002, 22(18):8277–8286
- Language: English
- Date: 2002
- Keywords
- Hippocampal commissure, Memory, Learning ,
LTP, Fear conditioning, Extinction, Agenesis, Mouse strains, Synaptic plasticity