The basal forebrain is a collection of structures located ventrally to the striatum. It is considered to be the major cholinergic output of the CNS. It includes a group of structures that lie near the bottom of the front of the brain, including the nucleus basalis, diagonal band of Broca, ventral pallidum and medial septal nuclei. These structures are important in the production of acetylcholine, which is then distributed widely throughout the brain. The adult basal forebrain/septum region volume was reduced in the AE treated young adults. Automated analysis found a −4.4% (Table 3; p<0.03) and manual analysis −4.5% decrease in forebrain/septal volume (Figure 8, **p<0.01). Forebrain/septum includes the nucleus basalis, diagonal band of Broca, and medial septal nuclei. The basal forebrain, through widespread projections to cortex, particularly prefrontal cortex, plays an important role in the modulation of cortical activity in association with different behavioral states including sleep, learning and memory (Everitt and Robbins, 1997; Jones, 2004; Sarter et al., 2003; Weinberger, 2003). By integrating images into a 3-dimensional rendering and overlaying forebrain (Figure 8), we show that the posterior
