Reports 2 experiments with 17 and 10 cats on the effects of entorhinectomies on passive-avoidance behavior. It was found that Ss with large bilateral lesions limited to entorhinal cortex were (a) impaired on the reversal but not the original learning of position habits, (b) displayed deficient passive-avoidance behavior, (c) were hyperactive in the open field, and (d) were hyperphagic for some days after the surgery. The lesions had no effect on the acquisition or the punishment extinction of a 1-way active-avoidance response. Control experiments showed that effects of entorhinectomy on position-habit reversals and open-field activity were not secondary to hyperphagia. The pattern of behavioral deficits suggests that the entorhinal region participates in the suppression of appetitively reinforced responses but not in the suppression of aversively reinforced responses. (23 ref.) (PsycINFO Database Record (c) 2006 APA, all rights reserved)