A behavioral analysis of the role of CA3 and CA1 subcortical efferents during classical fear conditioning.

It has been proposed that the hippocampus and subcortical structures interact during the processing of fear and anxiety-related information. It has been demonstrated that the subcortical efferents from CA3 and CA1 can be selectively disrupted without concomitant disruption to the afferents. The present experiment was designed to evaluate the role of CA3 efferents via the fimbria and the CA1 efferents via the dorsal fornix for encoding and consolidation/retrieval of classical fear conditioning. The present data suggest that the subcortical projections from CA3 and CA1 are differentially involved in the processing of classical fear conditioning, with CA3 subcortical efferents supporting acquisition of both cued and contextual fear but only supporting retention of contextual fear and CA1 subcortical efferents supporting the encoding and retrieval of both cued and contextual fear. These data further suggest that all hippocampal efferents are not homogeneous, and that the hippocampus and subcortex interact to process conditioned fear. Copyright (c) 2009 APA, all rights reserved.