Fig. 2.

Recording sites of VTA nondopamine neurons. The neuropil surrounding extracellularly recorded VTA non-DA neurons was stained with pontamine sky blue after electrophysiological evaluation. VTA non-DA neurons (filled circles) were localized along the rostrocaudal and dorsoventral extent of the VTA [shown here at 5.3, 5.6, 5.8, 6.0, and 6.3 mm from bregma (Paxinos and Watson, 1986)]; however, they tended to be encountered in clusters from 200 to 1000 μm dorsal to DA neurons. ip, Interpeduncular nucleus; ml, medial lemniscus;pn, paranigral nucleus; rmc, red nucleus, magnocellularis; snc, substantia nigra pars compacta;snr, substantia nigra pars reticulata;vta, ventral tegmental area.