Maclean, Paul D.

Paul MacLean, through his scientific research, made significant contributions to the fields of physiology, psychiatry, and brain research. Over the course of his long career, MacLean was instrumental in proposing and defining the triune concept of the brain. MacLeans evolutionary Triune Brain theory proposed that the human brain was in reality three brains in one; the R-complex, the Limbic system and the neocortex.

Paul MacLean was born in Phelps, New York on May 1, 1913, the third of four sons of a Presbyterian minister. He received his bachelors degree in English from Yale in 1935 and intended to study philosophy in Edinburgh, Scotland, but after a family illness, spent a year completing pre-medical work in Edinburgh instead. MacLean received his medical degree from Yale in 1940. During World War II, MacLean served as a medical officer in the Army from 1942-46. During his service with Yales 39th General Hospital Brigade in New Zealand, MacLean worked together with Dr. Averill Liebow to show that the diphtheria bacillus was a cause of tropical ulcers, paving the way for successful prophylaxis and treatment.

After leaving the Army in 1946, MacLean practiced medicine in Seattle and held a clinical appointment at University of Washington Medical School. From 1947-1949, MacLean was a USPHS Fellow at the Harvard Medical School/Massachusetts General Hospital, studying with Dr. Stanley Cobb. During this time, MacLean did research on psychomotor epilepsy and published his paper on the visceral brain(for which he introduced the term limbic system in 1952).

In 1949, MacLean joined the faculty of the Yale Medical School with a joint appointment in physiology and psychiatry. During his time at Yale, he also studied the brain mechanisms of emotion with Dr. John Fulton. In 1956 MacLean became Associate Professor of physiology. He spent a year on a National Science Foundation Senior Postdoctoral Fellowship at the Institute of Physiology in Zurich, Switzerland.

In 1957, MacLean came to NIH as the head of a new section on the limbic system in the Laboratory of Neurophysiology, National Institute of Mental Health. MacLean received the Distinguished Research Award of the Association for Research in Nervous and Mental Disease in 1964 and in 1966, gave the Thomas William Salmon Lectures at the New York Academy of Medicine. MacLean also received the G. Burroughs Mider Lectureship Award from the NIH in 1972.

In 1971 MacLean became the Chief of the Laboratory of Brain Evolution and Behavior, NIMH, newly opened in Poolesville, Maryland. MacLean was chief of the Laboratory of Brain Evolution and Behavior from 1971 to 1985, after which he was a Senior Research Scientist, Emeritus in the Department of Neurophysiology at NIMH.

From the guide to the Paul D. MacLean Papers, 1936; 1944-1993, (History of Medicine Division. National Library of Medicine)