ERIC Number: EJ910251
Record Type: Journal
Publication Date: 2010-Nov
Abstractor: As Provided
Reference Count: 0
Activation of the Infralimbic Cortex in a Fear Context Enhances Extinction Learning
Thompson, Brittany M.; Baratta, Michael V.; Biedenkapp, Joseph C.; Rudy, Jerry W.; Watkins, Linda R.; Maier, Steven F.
Learning & Memory, v17 n11 p591-599 Nov 2010
Activation of the infralimbic region (IL) of the medial prefrontal cortex (mPFC) reduces conditioned fear in a variety of situations, and the IL is thought to play an important role in the extinction of conditioned fear. Here we report a series of experiments using contextual fear conditioning in which the IL is activated with the GABAa antagonist picrotoxin (Ptx) during a single extinction session in the fear context. We investigate the impact of this manipulation on subsequent extinction sessions in which Ptx is no longer present. First, we demonstrate that a single treatment with intra-IL Ptx administered in a conditioned fear context greatly accelerates the rate of extinction on the following days. Importantly, IL-Ptx also enhances extinction to a different fear context than the one in which IL-Ptx was administered. Thus, IL-Ptx primes extinction learning regardless of the fear context in which the IL was initially activated. Second, activation of the IL must occur in conjunction with a fear context in order to enhance extinction; the extinction enhancing effect is not observable if IL-Ptx is administered in a neutral context. Finally, this extinction enhancing effect is specific to the IL for it does not occur if Ptx is injected into the prelimbic region (PL) of the mPFC. The results indicate a novel persisting control of fear induced by activation of the IL and suggest that IL activation induces changes in extinction-related circuitry that prime extinction learning.
Descriptors: Fear, Brain Hemisphere Functions, Learning Processes, Conditioning, Drug Use, Cues, Neurological Organization, Cognitive Processes
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Publication Type: Journal Articles; Reports - Research
Education Level: N/A
Authoring Institution: N/A