Atropine, scopolamine and hippocampal lesion effects on alternation performance of rats

Abstract

Interactions between effects of hippocampal lesions and cholinergic blocking agents were examined using two behavioral tasks, delayed spatial alternation and go-no go temporal alternation. Atrophine and scopolamine were administered to control rats and to rats with lesions in three areas of the hippocampal formation. Large hippocampal lesions disrupted performance on both tasks as did administration of atrophine or scopolamine to control rats and to rats with lesions in restricted areas of the hippocampus. However, the effects of atropine and scopolamine on performance of rats with large lesions involving all regions of the hippocampal formation depended upon the alternation task used. Atropine and scopolamine disrupted delayed spatial alternation performance of all groups tested, but atropine failed to significantly disrupt go-no go alternation performance of the group with large unrestricted hippocampal lesions. Both the size of the lesion and the behavioral task were found to be important determinants of the effects of cholinergic blockers on the performance of rats with hippocampal lesions.