Framework for internal sensation of pleasure using constraints from disparate findings in nucleus accumbens

Figure 2 Input and output connections of nucleus accumbens. One set of spines of medium spiny neurons (MSNs) in the nucleus accumbens receive excitatory inputs (red arrows) from several regions. The same spines of MSNs that receive excitatory inputs receive dopaminergic inputs (violet arrows) from ventral tegmental area (VTA). Another set of MSN spines receive inputs from inhibitory interneurons (orange arrow) in the VTA. Large green circles: Different brain regions. Small circles: Predominant cell types within brain regions (Red: Excitatory; Orange: Inhibitory; Violet: Dopaminergic). PFC: Prefrontal cortex; NAc: Nucleus accumbens; VTA: Ventral tegmental area.