Ji J, Maren S. Hippocampal involvement in contextual modulation of fear extinction. Hippocampus 17: 749-758

Department of Psychology, University of Michigan, 530 Church Street, Ann Arbor, MI 48109, USA.
Hippocampus (Impact Factor: 4.16). 09/2007; 17(9):749-58. DOI: 10.1002/hipo.20331
Source: PubMed


Extinction of fear conditioning in animals is an excellent model for the study of fear inhibition in humans. Substantial evidence has shown that extinction is a new learning process that is highly context-dependent. Several recovery effects (renewal, spontaneous recovery, and reinstatement) after extinction suggest that the contextual modulation of extinction is a critical behavioral mechanism underlying fear extinction. In addition, recent studies demonstrate a critical role for hippocampus in the context control of extinction. A growing body of evidence suggests that the hippocampus not only plays a role in contextual encoding and retrieval of fear extinction memories, but also interacts with other brain structures to regulate context-specificity of fear extinction. In this article, the authors will first discuss the fundamental behavioral features of the context effects of extinction and its underlying behavioral mechanisms. In the second part, the review will focus on the brain mechanisms for the contextual control of extinction.

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    • "Strong reciprocal connections were identified between posterior and anterior insula and perisylvian regions, frontal opercula, hippocampus and anterior cingulate cortex (Deen et al., 2011; Almashaikhi et al., 2014a,b). The hippocampus may also be particularly important for vestibular-anxiety system interactions, given its ability to process vestibular inputs for spatial orientation (Dieterich and Brandt, 2015) and its role in adding context to noxious experiences to extinguish aversive conditioning (LeDoux, 2000; Grillon, 2002; Kalisch et al., 2006; Ji and Maren, 2007; Alvarez et al., 2008; Indovina et al., 2011; Baldi and Bucherelli, 2015). The latter function may be particularly relevant in CSD. "
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    • "On the other hand, the vHC has been linked to spatial learning and memory (Kjelstrup et al. 2008) and emotional behaviors (Strange et al. 2014). In fact, its activity has been suggested to disrupt fear expression behaviors (Sotres- Bayon et al. 2012) and to promote extinction through contextdependent learning (Corcoran et al. 2005; Ji and Maren 2007). "
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    • "Finally, in the contextual fear extinction test, in which the hippocampus plays a critical role (Ji and Maren, 2007), Salm3 −/− mice showed normal fear extinction over the course of 5 days after memory acquisition (Figure 7M). Therefore, Salm3 −/− mice display unaltered hippocampus-dependent learning and memory in the tests administered in the present study. "
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