Inactivation of the Medial Prefrontal Cortex Interferes with the Expression But Not the Acquisition of Diff erential Fear Conditioning in Rats
Year: 2012
Type: article
Abstract: The medial prefrontal cortex (mPFC) has been implicated in the processing of emotionally significant stimuli, particularly the inhibition of inappropriate responses. We examined the role of the mPFC in regulation of fear responses using a differential fear conditioning procedure in which the excitatory conditioned stimulus (CS+) was paired with an aversive footshock and intermixed with the inhibitory conditioned stimulus (CS-). In the first experiment, using rats as subjects, muscimol, a gamma-amino-butyric acid type A (GABAA) receptor agonist, or artificial cerebrospinal fluid (aCSF) was infused intracranially into the mPFC across three conditioning sessions. Twenty-four hours after the last conditioning session, freezing response of the rats was tested in a drug-free state. Neither the muscimol nor the aCSF infusion had any effect on differential responding. In the second experiment, the same experimental procedure was used except that the infusion was made before the testing session rather than the conditioning sessions. The results showed that muscimol infusion impaired differential responding: the level of freezing to CS- was indiscriminable from that to CS+. Taken together, these results suggest that the mPFC is responsible for the regulation of fear response by inhibiting inappropriate fear expressions.
Source: Experimental Neurobiology
Authors: Yeon Kyung Lee, June-Seek Choi
Institution: Korea University
Language: English
Topic: Memory and Neural Mechanisms
Subfield: Cognitive Neuroscience
Field: Neuroscience
Domain: Life Sciences
Open Access status: bronze
OpenAlex ID: W2150524690