Differential effects of pretraining inactivation of the right or left amygdala on retention of inhibitory avoidance training.

Rats with bilateral cannulas aimed at the amygdalae received bilateral infusions of either buffer or lidocaine hydrochloride, or unilateral infusions of each, 5 min before continuous multiple-trial inhibitory avoidance (CMIA) training. Retention was tested 48 hr later. Some of the rats were retrained at this time and tested again 48 hr later. Bilateral infusions of lidocaine prior to the initial training impaired acquisition, retention, and relearning of the CMIA task. Unilateral infusions of lidocaine into the right or left amygdala did not affect acquisition. Rats given lidocaine into the right amygdala were impaired on retention 48 hr later. The findings are consistent with others indicating involvement of the amygdala in acquisition and consolidation of aversively motivated learning and suggest possible differential involvement of the right and left amygdalae in memory consolidation.