SELECTIVE IMMUNOTOXIC LESIONS OF BASAL FOREBRAIN CHOLINERGIC CELLS - EFFECTS ON LEARNING AND MEMORY IN RATS

Male Long-Evans rats were given injections of either 192 IgG-saporin, an apparently selective toxin for basal forebrain cholinergic neurons (LES), or vehicle (CON) into either the medial septum and vertical lim b of the diagonal band (MS/VDB) or bilaterally into the nucleus basali s magnocellularis and substantia innominata (nBM/SI). Place discrimina tion in the Morris water maze assessed spatial learning, and a trial-u nique matching-to-place task in the water maze assessed memory for pla ce information over varying delays. MS/VDB-LES and nBM/SI-LES rats wer e not impaired relative to CON rats in acquisition of the place discri mination, but were mildly impaired relative to CON rats in performance of the memory task even at the shortest delay, suggesting a nonmnemon ic deficit. These results contrast with effects of less selective lesi ons, which have been taken to support a role for basal forebrain choli nergic neurons in learning and memory.