Mahlon R. DeLong is an American neurologist and professor at the Medical School of Emory University. He succeeded in attaining major progress in the research and treatment of Parkinson's disease, dystonia, tremor and other neurological movement disorders. In 1971, he and Russell T. Richardson did experiments with monkeys to find out first groups of neurons, which are involved in the pathogenesis conditioned learning and they revealed the role played by the neurotransmitter acetylcholine.
DeLong attended Harvard Medical School, completed his internship at Boston City Hospital and his residency training at Johns Hopkins Hospital in Baltimore with the professional doctorate in 1976. And, in 1971 he worked at the National Institute of Mental Health in Bethesda. He received his license in 1980 as a neurologist and researcher at the Johns Hopkins University. From 1990 he was at Emory University, where he is William Patterson Timmie Professor of Neurology since 1993. He is a member of the Dana Alliance for Brain Initiative. In 2014 he received the Breakthrough Prize in Life Sciences for defining the interlocking circuits in the brain that malfunction in Parkinson's disease.