Investigating the role of dopamine receptor- and parvalbumin-expressing cells in extinction of conditioned fear

Abstract

The present study examined the pattern of activation of neurons that express dopamine receptors 1 and 2 (D1R and D2R), and parvalbumin (PV) in mice that underwent extinction of a fear memory. Adult male transgenic mice expressing D1R or D2R tagged with green fluorescent protein (GFP) were conditioned with 6 tone-shock pairings. The following day they were randomly divided into one of four experimental groups: extinction, retrieval, context or handled. Extinction groups were exposed to 45 tone presentations, retrieval groups were exposed to 5 tone presentations and the context groups were exposed to the chamber without any tones. Ninety minutes following their assigned treatment, mice were pe..