  Distribution of acetylcholinesterase (AChE) activity in the septum of the
telencephalon in man was studied in 15 human brains using the acetylthiocholine
method. Highest activity of AChE was found in the nucleus of the diagonal band
and nucleus accumbens, and lowest in the Lateral nucleus. Comparison of
histochemical results with cellular structure and wi.th the course of fibers
showed absence in man of some of the nuclei described in animals such as the
anterior medial nucleus, triangular nucleus, and marked reduction of the
septo-hippocampal nucleus and fimbriate nucleus. Areas of the septum showing
AChE activity were divided into an anterior and posterior system. The
applicability to man of some neurophysiologic findings in animals is discussed.
