Abstract: | Trained 12 male Wistar rats with bilateral lesions in the amygdala to barpress on an FI schedule of reinforcement. During test trials, when reinforcement was occasionally omitted, response rates of 12 controls increased in the subsequent interval, whereas lesioned Ss showed no significant change. In Exp II Ss received fixed-ratio reinforcement on 1 lever, which was followed by a time-out period and fixed-ratio reinforcement on a 2nd lever. Results indicate that after reinforcement was withheld Ss with damage in the amygdala did not increase responding in the subsequent time-out period, whereas controls showed significantly higher rates. Differential latencies to initiation of response after nonreinforcement were also found. The deficits following brain damage are attributed to a reduction in nonreinforcement-induced frustration. (20 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved) |