The basal forebrain is a group of structures that lie near the bottom of the front of the brain. It includes the nucleus basalis, diagonal band, medial septum, and substantia innominata. It is considered to be the major cholinergic output of the central nervous system (CNS). These structures are important in the production of acetylcholine, which is then distributed widely throughout the brain. Basal forebrain damage can result in memory impairments such as amnesia and confabulation.