Figure 1.

(A) Representative photomicrographs of adjacent basal forebrain sections in wild-type and mutant animals stained for ChAT and TrkA, respectively, demonstrating that one-third of cholinergic neurons are absent in the medial septum and VLDB of mutants. (B) Photomicrographs of low- and high-power fields of the septal/diagonal band cholinergic projections to the hippocampus of wild-type and mutant animals stained for ChAT. Results demonstrate a striking reduction in cholinergic innervation within the CA1 and CA2 fields and the molecular layers of the hippocampus in the mutant animals. CA1, CA2, and CA3, hippocampal subfields; cc, corpus callosum; DG, dentate gyrus; GrDG, granular layer of the DG; Mol, molecular layer of the hippocampus; Or, stratum oriens; PoDG, polymorphic layer of the DG; Py, pyramidal cell layer of the hippocampus.