Fig. 4.     Quantitative comparison of the four markers (ChAT, PV, CR and CB) in different basal forebrain structures. Ordinate indicates cell number counted in both sides in each structure using 48 alternately stained sections. Note the ratio of cholinergic cells to the other three non-cholinergic neurons varies from 1:3-4 (MS-VDB; HDB; VP; IC) to 1:8 (GP, SI-BST). VP = ventral pallidum; IC = internal capsule; BST = bed nuclus of the stria terminalis.