Faculty Collaboration Database

Trace and contextual fear conditioning are impaired following unilateral microinjection of muscimol in the ventral hippocampus or amygdala, but not the medial prefrontal cortex. Neurobiol Learn Mem 2012 May;97(4):452-64

Date

04/04/2012

Pubmed ID

22469748

Pubmed Central ID

PMC3358523

DOI

10.1016/j.nlm.2012.03.009

Scopus ID

2-s2.0-84861189045 (requires institutional sign-in at Scopus site)   86 Citations

Abstract

Trace fear conditioning, in which a brief empty "trace interval" occurs between presentation of the CS and UCS, differs from standard delay conditioning in that contributions from both the hippocampus and prelimbic medial prefrontal cortex (PL mPFC) are required to form a normal long term memory. Little is currently known about how the PL interacts with various temporal lobe structures to support learning across this temporal gap between stimuli. We temporarily inactivated PL along with either ventral hippocampus or amygdala in a disconnection design to determine if these structures functionally interact to acquire trace fear conditioning. Disconnection (contralateral injections) of the PL with either the ventral hippocampus or amygdala impaired trace fear conditioning; however, ipsilateral control rats were also impaired. Follow-up experiments examined the effects of unilateral inactivation of the PL, ventral hippocampus, or amygdala during conditioning. The results of this study demonstrate that unilateral inactivation of the ventral hippocampus or amygdala impairs memory, while bilateral inactivation of the PL is required to produce a deficit. Memory deficits after unilateral inactivation of the ventral hippocampus or amygdala prevent us from determining whether the mPFC functionally interacts with the medial temporal lobe using a disconnection approach. Nonetheless, our findings suggest that the trace fear network is more integrated than previously thought.

Author List

Gilmartin MR, Kwapis JL, Helmstetter FJ

Author

Fred Helmstetter PhD Professor in the Psychology / Neuroscience department at University of Wisconsin - Milwaukee

MESH terms used to index this publication - Major topics in bold

Amygdala
Animals
Conditioning, Classical
Fear
Freezing Reaction, Cataleptic
GABA-A Receptor Agonists
Hippocampus
Male
Memory, Long-Term
Muscimol
Prefrontal Cortex
Rats
Rats, Long-Evans