[1] Most neurons of the nucleus basalis are rich in the neurotransmitter acetylcholine, and they have widespread projections to the neocortex and other brain structures.

[1] The nucleus basalis is thought to consist of several subdivisions based on the location of the cells and their projections to other brain regions.

[3] Studies of the firing patterns of nucleus basalis neurons in nonhuman primates indicate that the cells are associated with arousing stimuli, both positive (appetitive) and negative (aversive).

[7] The first (A) is a bottom-up component in which the input to the higher visual cortex (where conscious perception takes place) comes from the retina via the lateral geniculate body and V1.

[2] The resulting decrease in acetylcholine in the brain is thought to contribute to the decline in mental function of affected patients.

[3][2] For this reason, most currently available pharmacological treatments for dementia focus on compensating for faltering function of the nucleus basalis through artificially increasing acetylcholine levels.