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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
9
pubmed:dateCreated
2009-7-14
pubmed:abstractText
The medial prefrontal cortex (mPFC) has been proposed to be essential for extinction of fear memory, but its neural mechanism has been poorly understood. The present study examined whether synaptic transmission in the hippocampal-mPFC pathway is related to extinction of context-dependent fear memory in freely moving rats using electrophysiological approaches combined with behavioral analysis. Population spike amplitude in the mPFC was decreased during the first extinction trial by exposure to contextual fear conditioning. This synaptic inhibition was reversed by repeated extinction trials, accompanied by decreases in fear-related freezing behavior. These results suggest that alteration of synaptic transmission in the hippocampal-mPFC pathway is associated with the extinction processes of context-dependent fear memory. Further experiments were performed to elucidate whether early postnatal stress alters the synaptic response in the mPFC during extinction trials using a juvenile stress model, based on our previous findings that early postnatal stress affects the behavioral response to emotional stress. Adult rats that previously were exposed to five footshocks (FS) (shock intensity, 0.5 mA; intershock interval, 28 seconds; shock duration, 2 seconds) at postnatal day 21 to 25 (week 3; 3W-FS) exhibited impaired reversal of both inhibitory synaptic transmission and freezing behavior induced by repeated extinction trials. The neuronal and behavioral deficits observed in the 3W-FS group were prevented by pretreatment with the serotonin(1A) receptor agonist tandospirone (1 mg/kg, i.p.). These results indicate the possiblity that aversive stress exposure during the third postnatal week impaired extinction processes of context-dependent fear memory. The deficits in extinction observed in the 3W-FS group might be attributable to dysfunction of hippocampal-mPFC neural circuits involving 5-HT(1A) receptor mechanisms.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Sep
pubmed:issn
1098-2396
pubmed:author
pubmed:copyrightInfo
2009 Wiley-Liss, Inc.
pubmed:issnType
Electronic
pubmed:volume
63
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
805-13
pubmed:dateRevised
2010-11-18
pubmed:meshHeading
pubmed-meshheading:19504621-Action Potentials, pubmed-meshheading:19504621-Animals, pubmed-meshheading:19504621-Conditioning (Psychology), pubmed-meshheading:19504621-Disease Models, Animal, pubmed-meshheading:19504621-Electric Stimulation, pubmed-meshheading:19504621-Extinction, Psychological, pubmed-meshheading:19504621-Fear, pubmed-meshheading:19504621-Freezing Reaction, Cataleptic, pubmed-meshheading:19504621-Hippocampus, pubmed-meshheading:19504621-Male, pubmed-meshheading:19504621-Memory, pubmed-meshheading:19504621-Neural Inhibition, pubmed-meshheading:19504621-Neural Pathways, pubmed-meshheading:19504621-Neuronal Plasticity, pubmed-meshheading:19504621-Neurons, pubmed-meshheading:19504621-Neuropsychological Tests, pubmed-meshheading:19504621-Prefrontal Cortex, pubmed-meshheading:19504621-Rats, pubmed-meshheading:19504621-Rats, Wistar, pubmed-meshheading:19504621-Receptor, Serotonin, 5-HT1A, pubmed-meshheading:19504621-Serotonin, pubmed-meshheading:19504621-Serotonin 5-HT1 Receptor Agonists, pubmed-meshheading:19504621-Serotonin Receptor Agonists, pubmed-meshheading:19504621-Stress, Psychological, pubmed-meshheading:19504621-Synaptic Transmission
pubmed:year
2009
pubmed:articleTitle
Alteration of synaptic transmission in the hippocampal-mPFC pathway during extinction trials of context-dependent fear memory in juvenile rat stress models.
pubmed:affiliation
Department of Dental Anesthesiology, Health Sciences University of Hokkaido, Ishikari-Tobetsu, Japan.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't