|Dopamine (DA) exerts its major role in the nervous system where it is involved in motor control and action selection, reward and motivation, behavior, memory and cognition. The many effects are achieved through the projections dopaminergic (DA-producing) neurons establish and the inputs they receive which shape DA release. DA neurons in midbrain areas such as the substantia nigra pars compacta (SNc) and the ventral tegmental area (VTA), project to the striatum or the cerebral cortex to form specific neural pathways. Projections from the SNc to the dorsal striatum (caudate-putamen in primates) form the nigrostriatal system; from the VTA to the nucleus accumbens (NAc) and from the VTA (and SNc in primates) to the cortex, in particular the frontal lobes (prefrontal cortex, PFC), form the mesolimbic and the mesocortical system, respectively, sometimes collectively referred to as the mesocorticolimbic system. These are the three main DA systems. DA signals through five G protein-coupled receptors that are subdivided into two types, selectively expressed in target neurons. The role DA plays is largely modulatory. Click here to explore DA signaling and the systems it modulates.