Effect of bilateral hippocampal destruction on the acquisition and extinction of an operant response

Abstract

Rats suffering radical bilateral hippocampal destruction, partial, destruction of the posterolateral neocortex (control animals), and unoperated rats were given long experience with CRF (continuous reinforcement) and then shifted to a simple extinction schedule. Twice during the extinction phase of the experiment, the animals were given 30 response-contingent reinforcements. The hippocampectomized subjects were not found to respond more than the other animals on the CRF or extinction schedules; but did, however, show greater increases in their bar press rates after experiencing the 30 reinforced responses. An activity measure was taken of all animals before and after certain training sessions. Hours of food deprivation were found to differentially affect the activity levels of the lesioned and non-lesioned subjects.