Localization of the microdialysis probe in the basal forebrain. A is a schematic figure from the rat brain atlas of Paxinos and Watson (2006), and the location of the microdialysis probe is depicted by a small black rectangle. The larger rectangle represents the area depicted by the photomicrographs in B and C. B, Photomicrograph of the track of the microdialysis probe in the basal forebrain of a representative saline control rat with the tip of the probe surrounded by cholinergic neurons. C, Photomicrograph of the track in a representative rat administered 192-IgG-Sap, which kills the BF cholinergic neurons. AC, Anterior commissure; CPu, caudate–putamen; OT, optic tract. Scale bar, 200 μm.