Within the tegmentum, the red nucleus is in charge of motor coordination (specifically for limb movements) and the periaqueductal gray matter (PAG) contains critical circuits for modulating behavioral responses to pains.

In addition, the substantia nigra forms reciprocal connections with the basal ganglia which are highly correlated with motor functions and learning.

For instance, when the dopamine neurons are lost from the substantia nigra, the condition of extreme muscle rigidity occurs as in the Parkinson's disease.

Because of this pathway regulates the experience of reward and pleasure, it is not surprising to see that food and drugs affect it the most in terms of a loss of impulse control.

Moreover, excessive mesolimbic dopamine activity plays a role in schizophrenia, a behavioral disorder characterized by delusions, hallucinations, blunted emotion, agitation, etc.