This diagram represents a sagittal section of the rat brain. Highlighted are the nuclei representing the limbic structures of the basal forebrain including the amygdala, hippocampus, prefrontal cortex (PFC), nucleus accumbens (N. Acc.), ventral pallidum (VP) and ventral tegmental area (VTA). Dopaminergic neurons in the VTA modulate information flow through the limbic circuit via projections to the nucleus accumbens, amygdala, hippocampus, PFC and VP. Increased dopaminergic transmission in limbic nuclei, particularly the nucleus accumbens, underlies the reinforcing effect of virtually every abused drug. Note that psychostimulants increase dopaminergic transmission in areas receiving projections from the VTA via interactions with dopamine transporters.