The tail of the ventral tegmental area in behavioral processes and in the effect of psychostimulants and drugs of abuse

The tail of the ventral tegmental area (tVTA) is a recently identified structure that exerts a major inhibitory drive onto midbrain dopamine (DA) neurons. Also referred to as the rostromedial tegmental nucleus (RMTg), the tVTA is a cluster of gamma-aminobutyric acid (GABA)ergic neurons that starts within the posterior end of the VTA, where it is restricted dorsolateral to the caudal part of the interpeduncular nucleus, and extends into the pons. First identified in the rat, the tVTA has been described in many species, including mice and monkeys, as a region exhibiting similar anatomical and behavioral properties; it receives strong excitatory inputs from the lateral habenula (LHb), conveys negative reward-related information, and inhibits midbrain DA neuron activity. As an important inhibitory afferent to midbrain DA neurons, the tVTA is also implicated in drug abuse and in the complex interplay between reward and aversion processes. The overarching goal of this review is to provide the current state of knowledge on the anatomy and connectivity of the tVTA and to discuss recent evidence implicating this structure in reward-related processes and in the effect of psychostimulants and drugs of abuse.