Effects of frontal cortex lesions on differentiation and extinction of the classically conditioned nictitating membrane response in rabbits.

In Exp I 8 male New Zealand rabbits with frontal lesions, compared to 10 Ss with Visual Area II lesions, were impaired in relearning an auditory differentiation involving a classically conditioned defensive response (movement of the nictitating membrane). In Exp II it was shown that frontal lesions in 6 additional Ss also produced perseveration of this response in extinction. Analysis of these findings suggests that frontal lesions impair the ability to suppress conditioned nictitating membrane responses. Results support the view that frontal ablation produces a general impairment in overcoming strong response tendencies independently of the kind of response or reinforcement. (16 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)