Methylphenidate, amygdalectomy, and active avoidance performance in the rat.

64 male Sprague-Dawley amygdalectomized and control rats were given 400 active avoidance training trials in a shuttle box. Controls received 0, 4, 8, or 16 mg/kg of methylphenidate throughout acquisition. Amygdalectomized Ss were given the 1st 200 trials without drug, followed by 200 trials with drug. Administration of methylphenidate produced an abrupt and large improvement in performance in the amygdalectomized Ss. One month after acquisition under the drug, retraining without drug revealed a significant retention effect for the 3 amygdaloid-drug groups relative to the nondrug-amygdaloid group. Results indicate that although amygdalectomy impairs the performance of avoidance responses, it does not prevent the learning or retention of such responses. Since methylphendiate appears to act primarily on dopaminergic mechanisms, the possible influence of amygdalectomy on such mechanisms is discussed. (41 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)