Dopaminergic Activity in the Medial Prefrontal Cortex Modulates Fear Conditioning.

The purpose of the present study was to determine the role of medial prefrontal cortex (mPFC) dopaminergic system in fear conditioning response considering individual differences. Animals were initially counterbalanced and classified based on open field test, and then were given a single infusion of the dopamine agonist, amphetamine (AMPH) and antagonist, clozapine (CLZ) into the medial prefrontal cortex. Rats received tone-shock pairing in a classical fear conditioning test and then exposed to the tone alone. Freezing responses were measured as conditioned fear index. The results showed that both AMPH and CLZ infusion in mPFC reduced the expression of conditioned fear. This finding indicates that elevation or reduction in the dopaminergic activity is associated with the decrease of fear responses, despite preexisting individual-typological differences. [ABSTRACT FROM AUTHOR]