FIG. 4.
(A–C) Summary diagram of rostro-caudal distribution of cells expressing VGluT2 (closed circles) or TH (open circles) mRNAs in the VTA. Note that cells expressing TH mRNA are most densely aggregated in the caudal VTA, where cells expressing VGluT2 mRNA are sparse. Also, in the rostral and medial VTATH neurons are more densely aggregated in the PBP than in the PN or VTAR, where the converse is true for VGluT2 cells. Cells expressing VGluT2 mRNA or TH mRNA in neighbouring areas of the VTA are not included in the diagram. MT, medial terminal nucleus of the accessory optic tract; ml, medial lemniscus. Subregions of the VTA are named according to Paxinos & Watson (2005). Bregma −5.04 mm for A, −5.28 mm for B and −5.52 mm for C.