Extensive Lesions of Cholinergic Basal Forebrain Neurons Do Not Impair Spatial Working Memory

Abstract

A recent studysuggests that lesions to all major areas of the cholinergic basal forebrain in the rat (medial septum, horizontal limb of the diagonal band of Broca, and nucleus basalis magnocellularis) impair a spatial working memory task. However, this experiment used a surgical technique that mayhave damaged cerebellar Purkinje cells. The present studytested rats with highlyselective lesions of cholinergic neurons in all major areas of the basal forebrain on a spatial working memorytask in the radial arm maze. In postoperative testing, there were no significant differences between lesion and control groups in working memory, even with a delayperiod of 8 h, with the exception of a transient impairment during the first 2 d of postoperative testing at shorter delays (0 or 2 h). This finding corroborates other results that indicate that the cholinergic basal forebrain does not playa significant role in spatial working memory. Furthermore, it underscores the presence of intact memoryfunctions after cholinergic basal forebrain damage, despite attentional impairments that follow these lesions, demonstrated in other task paradigms.