Abstract

The influence of dorsal hippocampal lesions upon a task which subjects behaved conditionally was examined. The task required that hungry rats learn to turn to the right in the illuminated condition and to the left in the unilluminated condition for food in the same T-maze. The behavior of 10 rats with bilateral hippocampal lesions was compaired with that of 9 sham-operated control subjects. Compaired with the control subjects, hippocampal subjects (a) took more trials to reach criterion on the T-maze task which required the conditional operation (P< .01). (b) Showed the tendency of response perseveration and (c) Showed more correct responses on a retention test (P<.01). These results were well interperted in the framework of 'conditional operation' by Hirsh. In turn, they were not well accounted for by the response perseveration hypothesis, spatial mapping hypothesis of O'keefe, or working memory hypothesis of Olton.