Edward Evarts
Encyclopedia
Edward Vaughan Evarts was an American neuroscientist
. He pioneered single-unit recordings from the brains of awake, behaving monkey
s.
and an M.D. degree from Harvard Medical School
in 1948. Evarts undertook an internship at Boston's Peter Bent Brigham Hospital, worked with Karl Lashley
at Yerkes Laboratories of Primate Biology in Orange Park, Florida, and at the National Hospital for Nervous Diseases in London. After a residency in psychiatry at the Payne Whitney Institute in New York, Evarts joined NIMH in Bethesda, Maryland where he was appointed as head of the Section on Physiology at the Laboratory of Clinical Science and became chief of the Laboratory of Neurophysiology in 1970. Evarts remained in that position until he died, in his laboratory, July 2, 1985.
Evarts started his neurophysiological research by conducting ablation studies of visual and auditory cortex in monkey
s. 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 ("go-cue") is being prepared. "Transcortical reflex" describes the operation of motor cortex in the way similar to spinal reflexes that influence spinal motoneuron firing.
. His followers use single electrodes and electrode arrays temporarily inserted or implanted in the brain to record brain signals during different types of behavioral and cognitive activity and thereby gain knowledge about how the brain works. The knowledge accumulated in this research recently resulted in creation of brain-computer interface
s—electronic devices that sample neuronal activity in the brain, decode its meaning and use decoded information to operate external devices, such as robot
s.
Neuroscientist
A neuroscientist is an individual who studies the scientific field of neuroscience or any of its related sub-fields...
. He pioneered single-unit recordings from the brains of awake, behaving monkey
Monkey
A monkey is a primate, either an Old World monkey or a New World monkey. There are about 260 known living species of monkey. Many are arboreal, although there are species that live primarily on the ground, such as baboons. Monkeys are generally considered to be intelligent. Unlike apes, monkeys...
s.
Life
Evarts received his undergraduate degree at Harvard CollegeHarvard College
Harvard College, in Cambridge, Massachusetts, is one of two schools within Harvard University granting undergraduate degrees...
and an M.D. degree from Harvard Medical School
Harvard Medical School
Harvard Medical School is the graduate medical school of Harvard University. It is located in the Longwood Medical Area of the Mission Hill neighborhood of Boston, Massachusetts....
in 1948. Evarts undertook an internship at Boston's Peter Bent Brigham Hospital, worked with Karl Lashley
Karl Lashley
-External links:*...
at Yerkes Laboratories of Primate Biology in Orange Park, Florida, and at the National Hospital for Nervous Diseases in London. After a residency in psychiatry at the Payne Whitney Institute in New York, Evarts joined NIMH in Bethesda, Maryland where he was appointed as head of the Section on Physiology at the Laboratory of Clinical Science and became chief of the Laboratory of Neurophysiology in 1970. Evarts remained in that position until he died, in his laboratory, July 2, 1985.
Evarts started his neurophysiological research by conducting ablation studies of visual and auditory cortex in monkey
Monkey
A monkey is a primate, either an Old World monkey or a New World monkey. There are about 260 known living species of monkey. Many are arboreal, although there are species that live primarily on the ground, such as baboons. Monkeys are generally considered to be intelligent. Unlike apes, monkeys...
s. He also studied effects of LSD
LSD
Lysergic acid diethylamide, abbreviated LSD or LSD-25, also known as lysergide and colloquially as acid, is a semisynthetic psychedelic drug of the ergoline family, well known for its psychological effects which can include altered thinking processes, closed and open eye visuals, synaesthesia, an...
and post-tetanic potentiation
Post-Tetanic Potentiation
Post-Tetanic Potentiation is a form of synaptic plasticity which is short-lived and results in increased frequency with no effect on amplitude in the spontaneous postsynaptic potential. It usually lasts in the range of several minutes...
in the cat visual system. Evarts made his most significant contribution to the field of neuroscience
Neuroscience
Neuroscience is the scientific study of the nervous system. Traditionally, neuroscience has been seen as a branch of biology. However, it is currently an interdisciplinary science that collaborates with other fields such as chemistry, computer science, engineering, linguistics, mathematics,...
and motor control
Motor control
Motor control are information processing related activities carried out by the central nervous system that organize the musculoskeletal system to create coordinated movements and skilled actions...
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 ("go-cue") is being prepared. "Transcortical reflex" describes the operation of motor cortex in the way similar to spinal reflexes that influence spinal motoneuron firing.
Influence
The work of Evarts gave rise to a new field in neuroscienceNeuroscience
Neuroscience is the scientific study of the nervous system. Traditionally, neuroscience has been seen as a branch of biology. However, it is currently an interdisciplinary science that collaborates with other fields such as chemistry, computer science, engineering, linguistics, mathematics,...
. His followers use single electrodes and electrode arrays temporarily inserted or implanted in the brain to record brain signals during different types of behavioral and cognitive activity and thereby gain knowledge about how the brain works. The knowledge accumulated in this research recently resulted in creation of brain-computer interface
Brain-computer interface
A brain–computer interface , sometimes called a direct neural interface or a brain–machine interface , is a direct communication pathway between the brain and an external device...
s—electronic devices that sample neuronal activity in the brain, decode its meaning and use decoded information to operate external devices, such as robot
Robot
A robot is a mechanical or virtual intelligent agent that can perform tasks automatically or with guidance, typically by remote control. In practice a robot is usually an electro-mechanical machine that is guided by computer and electronic programming. Robots can be autonomous, semi-autonomous or...
s.