Figure 9.

Map showing several sections through the basal forebrain ordered rostrocaudally from A to D and illustrating retrogradely labeled neurons following injection of the retrograde tracers cholera toxin β subunit (Ctβ) into the ventral tegmental area (circles) and Fluorogold (FG) into the rostromedial tegmental nucleus (crosses). Neurons exhibiting both tracers (double-labeled) are shown as red dots. Note that the double-labeled neurons are not located preferentially in any particular structure (see also Fig. 10). Quantitative comparisons should not be made given the disparity in robustness of retrograde labeling after FG versus Ctβ injections. See list for abbreviations.