Edward Evarts
Edward Vaughan Evarts was an American neuroscientist. He pioneered single-unit recordings from the brains of awake, behaving monkeys.
Life
Evarts was born in New York City in 1926 to Yachdiel Evarts and Mary Bowen Porter Evarts. His father was born to Russian parents who had immigrated to the US from Germany in 1890, when Edward Mark Evarts was one year old. Edward Vaughan Evarts received his undergraduate degree at Harvard College and a M.D. degree from Harvard Medical School in 1948. Evarts undertook an internship at Boston's Peter Bent Brigham Hospital. He worked with Karl Lashley at Yerkes Laboratories of Primate Biology in Orange Park, Florida beginning in 1949. Evarts married Josephine Semmes, a neuropsychologist. Evarts also worked at the National Hospital for Nervous Diseases in London. After a residency in psychiatry at the Payne Whitney Institute in New York, Evarts joined the National Institute of Mental Health in Bethesda, Maryland in 1953. He had initially been turned down by the Public Health Service because of a heart murmur, but Robert Felix and Robert Cohen had arranged a waiver for him. Evarts was appointed as head of the Section on Physiology at the Laboratory of Clinical Science of the NIMH and became chief of the Laboratory of Neurophysiology in 1970. Evarts remained in that position until he died, of a heart attack, in his laboratory, July 2, 1985.Evarts started his neurophysiological research by conducting ablation studies of visual and auditory cortex in monkeys. He also studied effects of LSD and post-tetanic potentiation in the cat visual system. Evarts made his most significant contribution to the field of neuroscience and motor control by pioneering electrophysiological recordings from single cortical neurons in awake monkeys. In his early studies using this technique, he compared sleep and waking states. He then conducted experiments that involved single-unit recordings from sensorimotor cortex in monkeys performing operantly conditioned movements. He observed modulations in the activity of single neurons that reflected movement parameters.
Based on these observations, he developed the concepts of "motor set" and "transcortical reflex". "Psychomotor set" describes neural activity that occurs when a motor action in response to a stimulus is being prepared. "Transcortical reflex" describes the operation of motor cortex in the way similar to spinal reflexes that influence spinal motoneuron firing.