Chapter II – The human basal forebrain. Part II

This chapter focuses on the human basal forebrain. It describes the anatomy of the ventral striatopallidal system and the extended amygdala. The basal forebrain consists largely of intermingling extensions of structures that are adjacent to it, and, as a consequence, it displays no distinct boundaries where it merges with the surrounding brain. The “basalis” region extends laterally underneath the anterior commissure and the globus pallidus into the dorsal aspect of the amygdaloid body. The basal nucleus of Meynert consists of a widely dispersed, more or less continuous collection of aggregated and non-aggregated, predominantly large, hyperchromatic projection neurons, and stretches obliquely from the septum-diagonal band area in the rostral part of the basal forebrain to the level of the caudal part of the amygdaloid body. The basal nucleus of Meynert projects to the cerebral cortex and the large majority of its corticopetal neurons are cholinergic.