Dopamine

A catecholamine neurotransmit- ter present in three circuits of the brain: one that regulates movement; a second, thought to be important for cognition and emotion; and a third that regulates the endocrine system. Deficits of dopamine in the motor circuit are associated with Parkinson’s disease. Abnormal- ities in the second circuit have been implicat- ed in schizophrenia.