MUSCIMOL INJECTED INTO THE RIGHT OR LEFT AMYGDALOID COMPLEX DIFFERENTIALLY AFFECTS RETENTION PERFORMANCE FOLLOWING AVERSIVELY MOTIVATED TRAINING

The effects of intra-amygdala infusion of the GABA(A) agonist, muscimo l, prior to retention testing was examined. In Expt. 1, rats were trai ned in a one-trial inhibitory-avoidance task and given bilateral intra -amygdala infusions of vehicle or muscimol or simultaneous unilateral infusions of each, 5 min before the retention test 24 h after training . Expt. 2 used the same procedures as those in Expt. 1 but two retenti on measures were taken: initial step-through latency and the number of trials to reach criterion during continuous multiple-trial inhibitory -avoidance (CMIA) training. Groups given bilateral infusions of muscim ol or unilateral infusion of muscimol into the right amygdala had sign ificantly shorter latencies to enter the dark compartment than groups given bilateral infusions of vehicle or unilateral infusion of muscimo l into the left amygdala. Bilateral muscimol infusions impaired acquis ition of CMIA relative to bilateral vehicle infusions or unilateral mu scimol infusion into the left amygdala. These results suggest differen tial involvement of the right and left amygdalae in memory.