Responses of Nucleus Basalis of Meynert Neurons in Behaving Monkeys

Cholinergic systems have long been implicated in memory processes since anticholinergic drugs disrupt performance on memory tasks in both human (Drachman, 1977; Mewaldt and Ghoneim, 1979) and nonhuman primates (Bartus, 1978; Ridley et al., 1984) and other species (Buresova et al., 1964; Deutsch, 1971; Squire et al., 1971). The source of cholinergic afferents to cerebral cortex has recently been found to lie primarily in the nucleus basalis of Meynert (NBM) (Lehman et al., 1980; Johnston et al., 1981; Mesulam et al., 1983; Pearson et al., 1983). Moreover, both the number of neurons in the NBM (Whitehouse et al., 1982; Arendt et al., 1983; Rogers et al., 1985) and the levels of cholinergic markers in cortex (Davies and Maloney, 1976; Perry et al., 1977; White et al., 1977) have consistently been found to be reduced in patients with Alzheimer’s disease. These findings have led to the hypothesis that the NBM may play an important role in learning and memory.