Response patterning and extinction in rats with hippocampal lesions.

Abstract

Rats that received hippocampal lesions, cortical lesions, or a control operation were administered runway training under single alternation (SA) or random (Rm) patterns of rewarded and nonrewarded trials, followed by extinction. Under SA training cortically damaged and operated control rats showed reliable response alternation: slower running after rewarded than after nonrewarded trials. Hippocampally damaged rats showed nonsignificant alternation. Under Rm training, differences in performance among groups and between rewarded and nonrewarded trials were nonsignificant. Resistance to extinction was reliably greater for Rm over SA training for cortically damaged and operated control rats. For hippocampally damaged rats SA and Rm yielded extinction results similar to each other and to cortically damaged and control rats trained under Rm.

Approach and consummatory behavior in rats with hippocampal lesions

“…Rats with lesions of the hippocampus are impaired on passive avoidance tasks (Isaacson & Wickelgren, 1%2;Kimble, 1%3;Kimura, 1958). These results are in agreement with studies on instrumental runway responses in which such animals are impaired when required to withhold a prepotent, or learned, motor response (Dalland , 1970;Franchina & Brown, 1970, 1970. However, rats with hippocampal ablations can withhold a prepotent consummatory response either as well as controls in a learned taste aversion (McGowan, Hankins, & Garcia, 1972;Murphy & Brown, 1974;Thomka & Brown , 1975) or even better than controls in a conditioned suppression test (Antelman & Brown, 1972).…”

The Hippocampus as a Cognitive Map

“…That is, continuously rewarded hippocampals extinguished more rapidly than did partially rewarded hippocampals. On the other hand, Franchina and Brown (1970) showed that hippocampal rats trained with either patterned or random partial reward in a runway extinguished at the same rate, which was roughly equivalent to that seen in intact rats given random partial-reward training. The authors concluded that the partial reinforcement effect was absent in the hippocampal rats; this conclusion would seem to us to be unwarranted.…”

“…The results of go-no-go alternation studies are presented in Table A25. With the exception of Franchina and Brown (1970) and Brunner, Haggbloom and Gazzara (1974), all studies have used an operant chamber. In the former runway study reward was available on alternate trials and good performance consisted in a particular pattern of latencies: long after reward and short after non-reward.…”

Cannabis: Neural Mechanisms and Behavior – a Theoretical Review

“…Goaldirected serial alternation is disrupted under A 9-THC in humans (104,105). An animal analog o f the goal-directed serial alternation task (non-spatial single alter nation) has been found to be disrupted by A 9-THC (111), atropine (145) and hippocampal lesions (50). Hippocampectomy disrupts other types of sequential behavior such as sequential bar pressing (84) while hippocampectomy, anti cholinergic drugs and low doses o f A9-THC impair spontaneous alternation (44,85,107,128).…”