Ventral Tegmental Area - Outputs

Outputs

The two primary efferent fiber projections of the VTA are the mesocortical and the mesolimbic pathways. Three less important pathways also exists: the mesostriatal, the mesodiencephalic, and the mesorhombencephalic pathways. Below is a brief summary of where each pathway originates and terminates:

• Mesostriatal: originates in the SN and VTA; innervates the anteromedial striatum
• Mesocortical: originates in the VTA; innervates the prefrontal and insular corticies
• Mesolimbic: originates in the VTA; innervates the limbic cortices, septo-hippocampal complex, nucleus accumbens (NAC), and amygdala
• Mesodiencephalic: originates in the SN and VTA; innervates several thalamic nuclei and several hypothalamic nuclei
• Mesorhombencephalic: originates in the SN and VTA; innervates the monoaminergic nuclei, superior colliculus, reticular formation, and periaqueductal gray

The large mesolimbic pathway projects primarily to the NAC and the olfactory tubercle. The projection is so named to contrast it with the nigro-striatal dopamine system that runs parallel to it but connects the substantia nigra to the dorsal striatum. Other projections of the VTA dopamine neurons include the limbic-related regions (i.e. septum, hippocampus, amygdala, and prefrontal cortex). The mesocortical pathway projects to sensory, motor, limbic, and polysensory association cortices. The prefrontal, orbitofrontal, and cingulate cortices receive the majority of innervation from the VTA. Most of these connections are unilateral, but some project to one or more areas.