Figure 6

Anterograde tracing of dopaminergic A13 projection cells and synaptic puncta to the MLR. (A–C) Anterograde fibers (GFP⁺, green) were noticed with clear labeling of synaptic puncta (mRuby⁺, magenta) in dlPAG, CnF and PPTg. The density of synaptic puncta was high in dlPAG as expected. We observed a dorsoventral gradient in synaptic density with higher synaptic density of mRuby⁺ punctas in CnF showing a sharp decline in the PPTg region. Scale bars A = 1000 µm, B–D = 20 µm and 10 µm. Atlas images adapted from template available from Allen Mouse Brain Atlas (2004)^39,90,91.