The cortical relationships of certain basal ganglia and the cholinergic basal forebrain nuclei.

Three groups of subcortical nuclei are related to the entire cerebral cortex, to the allocortex of the hippocampus and olfactory areas as well as the neocortex. The medial septal nucleus, the nucleus of the diagonal band and the basal nucleus send cholinergic fibers to the cortex: the striatum, neo- and ventral, receives fibers from the cortex and the claustrum has reciprocal cortical connections. In their neocortical relationships there are marked similarities between these groups.