Performance on delayed match following lesions of medial temporal lobe structures.

Abstract

Retention of delayed matching in monkeys from sample, at delays up to 5 sec., was measured following bilateral medial temporal lesions (MT) and after fractional amygdala-uncus (A) or hippocampal (H) lesions. Bilateral MT lesions produced a marked deficit in matching as well as in delayed matching. A lesions produced less marked impairment and H lesions produced no consistent impairment. The correlation between performance on match and performance on O-sec. delay was high. The conditional structure of the problem rather than the delay interval was the critical factor, although the absence of the sample stimulus differentially increased difficulty for MT and A groups.