Anterior limbic cortex and partial reinforcement effects on acquisition and extinction of a runway response in rats.

Abstract

24 hungry male albino rats received 100 acquisition trials in a runway followed by extinction trials; 12 Ss received alternating partial reinforcement (PRF) in acquisition and 12 received continuous reinforcement (CRF). Within each reinforcement condition 6 Ss had undergone electrolytic ablation of the anterior midline cortex 15 days before training. In acquisition both brain damage and the PRF schedule reduced run and goal speeds; in extinction brain-damaged CRF Ss had more response strength than intact CRF Ss, whereas PRF Ss with brain lesions showed less response strength than intact PRF Ss. The perseverative effect of PRF on extinction was observed in both intact and brain-damaged Ss. Data indicated that the lesions dissociated conditioned emotional goal responses from instrumental performance. (PsycINFO Database Record (c) 2006 APA, all rights reserved)