Changes in avoidance response latencies after prefrontal lesions in cats: group versus individual data.

Clear differences in proportion of short-latency bar-pressing avoidance responses were observed in two groups of cats trained to the same acoustic CS but against backgrounds of different intensities. Removal of the proreal and orbital gyri resulted in transient impartment of avoidance performance and in permanent decrease of short-latency avoidance responses. In the course of post-operative retraining the probability of avoidance responses increase, but mostly performed with latencies longer than those affected by prefrontal lesion. Similar effects of lesions and post-operative retraining were observed both on group averages and on individual data. Analysis of individual data indicates that the higher proportion of short-latency responses before operation, the more pronounced post-operative changes in response latencies.