Mark Hallett

Mark Hallett (1943 – November 2, 2025) was an American neurologist who researched the physiology of human movement and movement disorders including functional motor disorders at the NIH and served as Distinguished NIH Investigator Emeritus. Hallett worked at NIH for 40 years in the federal government, with several decades at the Human Motor Control Section and was previously chief of the Clinical Neurophysiology Laboratory at Brigham and Women's Hospital.

He was also considered a pioneer of the field of TMS and helped create the first conferences on TMS safety guidelines, as well as providing additional foundational research around principles of brain stimulation; he was awarded the 2019 International Brain Stimulation Award as a result.

Career Hallett graduated from Harvard with an AB and MD and trained at Peter Bent Brigham hospital and Massachusetts General Hospital. In the wake of diplomats suffering Havana Syndrome, Hallett was among the physicians asked to examine the diplomats. including reformulations of the Libet clock experiment, and an auditory paradigm to refine the measurement of the conscious intention to move. Furthermore, he investigated the potential causal role of conscious awareness in voluntary action, using a backward masking experiment.

Personal life and death Hallett was born in Philadelphia, Pennsylvania, in 1943 to Estelle (née Barg) and ophthalmologist Joseph W. Hallett. He married Judith Peller in 1966 shortly after her graduation from Wellesley College, and they had two children, Nicholas and Victoria. Hallett died from glioblastoma at home on November 2, 2025, at the age of 82.