Edgar Douglas Adrian Nobel Prize in Physiology or Medicine, 1932, jointly with Charles Sherrington Date of Birth: 30.11.1883 Country: Great Britain

1. Biography of Edgar Douglas Adrian
2. Research on Nerve Activity
3. Contributions to Sensory Perception
4. Later Years and Honors

Biography of Edgar Douglas Adrian

Edgar Douglas Adrian was a British electrophysiologist and researcher of the nervous system. He was awarded the Nobel Prize in Physiology or Medicine in 1932. Edgar was born to Alfred Douglas Adrian, a lawyer, and Flora Lavinia Adrian (Barton). He was the middle child in a family of three children. In 1908, Edgar graduated from prestigious Westminster School and entered Trinity College, Cambridge University to study natural sciences. Here, he worked under the guidance of physiologist Keith Lucas, who was studying the reactions of nerves and muscles to electrical stimulation. Edgar soon joined these studies. In 1871, it was established that the reaction of the heart muscle to electrical stimulation follows the "all or none" law - either the reaction is maximum or it does not occur at all. In 1905, Lucas showed that special reactions, determined by the change in the number of excited fibers and the frequency of their contraction, are characteristic not only for the heart but also for any other muscles. Although Lucas' subsequent experiments provided serious evidence that nerves also exhibit reactions that follow the "all or none" law, there was no direct evidence of this as there was no way to record the activity of individual nerve cells at that time. In their work, Edgar and Lucas studied whether the energy of the stimulus serves as a source of energy for the propagation of a nerve impulse (action potential), similar to how a bullet flies, or whether this process is a self-sustaining reaction, like the spread of flame along a wick. Their data supported the second assumption. However, it was not until the 1940s that Alan Hodgkin and Andrew Huxley revealed the mechanism of action potential generation. In 1911, Edgar graduated from Cambridge University and two years later became a research fellow at Trinity College. By this time, he had come to the conclusion that knowledge of medicine would help him in his scientific work, and shortly before the start of World War I, he began working at St. Bartholomew's Hospital in London. In record time - just over a year - Edgar completed his medical practice. During the war years, he remained in England, studying and treating concussions and neurological injuries.

Research on Nerve Activity

Until Lucas' death in an aviation accident in 1961, he and Edgar discussed possible methods of recording the electrical activity of individual nerve fibers. By that time, it was known that the duration of these impulses is only a few thousandths of a second, and their magnitude is a few microvolts. All this did not allow recording such impulses using the available equipment at that time. Lucas suggested trying to record electrical signals from nerves using thermionic tubes, similar to those invented by Guglielmo Marconi and Ferdinand Braun. However, since the influx of students had sharply increased after the war, Edgar had to devote a lot of time to teaching, and Lucas' idea could not be implemented for several years. However, although scientific activity took a back seat for Edgar, he made several important observations regarding the refractory period of nerves and muscles (i.e., the period of time immediately after an electrical impulse when the tissue is unexcitable), and in 1922, together with American neurobiologist Alexander Forbes, obtained convincing data in favor of the fact that sensory nerves, like motor ones, follow the "all or none" law. This discovery was unexpected, as at that time, most scientists believed that the information traveling along sensory nerves was too complex and could not be encoded by such simple impulses.

Contributions to Sensory Perception

In 1925, Edgar began using valve amplifiers in his experiments. By that time, Herbert Gasser and his colleagues from the Johns Hopkins Medical School had created an amplifier that made it possible to record action potentials in bundles of motor nerve fibers. Edgar constructed his own amplifier based on Gasser's scheme and tested it in experiments on nerves innervating frog muscles. Previously, Charles Sherrington had suggested that sensory nerves originate from muscles, perceiving the stretching of these muscles. Edgar was able to isolate a muscle fragment that contained only one sensory receptor; this receptor was excited when the muscle stretched. It turned out that all impulses in the nerve from this receptor have exactly the same duration and amplitude. However, as Edgar later wrote, "the frequency (of impulses) depends on the degree and rate of stretching, i.e., on the degree of excitation of the sensory organ. In this regard, impulse frequency carries much more information than just a signal that excitation has occurred." Over the next few years, Edgar and his colleagues studied impulse patterns in various sensory and motor nerves, and the results of their research became the basis for the development of a general theory of sensory perception. According to Edgar's ideas, human sensory receptors only respond to changes in the environment and adapt to the new situation after the change has occurred. The frequency of impulse generation in sensory nerves depends on the intensity of receptor excitation.

Later Years and Honors

In subsequent years, Edgar described the entire process from receptor excitation to its perception by the brain. He wrote, "Receptor excitation gradually fades, and as it fades, the intervals between impulses in sensory fibers become longer. These impulses are integrated through certain central processes, and thanks to this, the increase and decrease of sensation represents a fairly accurate copy of the increase and decrease of receptor excitation. As for the nature of sensation, it obviously depends on the path along which the impulses travel." In other words, all impulses in sensory nerves are the same. Light is perceived as light, and sound is perceived as sound not because there is any fundamental difference between the sensory processes in the organs of vision or hearing, but because the brain interprets any excitation of visual nerves as light and auditory nerves as sound. In experiments on motor nerves, Edgar discovered that "the possible variety of signals sent through motor nerves to muscles... is limited to the same extent as the occurrence of impulses in sensory nerves. Here, too, the magnitude of the effect is determined by the frequency of impulse generation and the number of excited fibers." Edgar's discoveries regarding adaptation and encoding of nerve impulses allowed researchers to conduct a comprehensive and objective study of sensations.

In 1932, Edgar, along with Charles Sherrington, was awarded the Nobel Prize in Physiology or Medicine "for discoveries regarding the functions of nerve cells." In his speech at the award ceremony, Goran Liljestrand, a researcher from the Karolinska Institute, said, "Edgar's work has made a significant contribution to our understanding of the principles of nerve cell activity and the adaptation of sensory organs." By that time, Edgar's interests had shifted from peripheral sensory organs to the brain. His studies on electrical signals in the brain in the early 1930s became an important contribution to the development of electroencephalography as a method for studying the brain.

For the next 20 years, Edgar experimentally studied various objects - the auditory analyzer, sensory cortex (areas of the brain responsible for processing complex sensory signals), cerebellum, vestibular apparatus, and olfactory organs. Perhaps all these studies were his stepping stones towards solving the general task of understanding the activity of the central nervous system as a whole. A skilled experimenter, he sometimes conducted experiments on himself. For example, once Edgar inserted a long needle into his shoulder and used it to record the activity of his own muscles for two hours.

In 1951, Edgar left his position as Professor of Physiology at Cambridge University and became the Master of Trinity College. Due to this, he had to devote a significant amount of time to administrative work, lecturing, and political activities. From 1950 to 1955, Edgar held the position of President of the Royal Society of London, of which he had been a member since 1923. As President of the Royal Society, he also served as President of the British Association for the Advancement of Science for a year, simultaneously leading both organizations, which was the third case in their history.
From 1957 to 1959, Edgar was Pro-Vice-Chancellor of Cambridge University, and from 1968 to December 1975, he served as its Chancellor. Alan Hodgkin recalled that "when Edgar became Chancellor, the Trinity College rowing team asked him to honor them by allowing them to row him upstream from Trinity College to the university center. Although Edgar was already 78 years old at the time, he agreed and, dressed in official attire, took the helm himself and successfully navigated the boat through numerous bridges against the current."

The highest honor in Edgar's life came in 1955 when Queen Elizabeth II granted him the title of Baron. As Baron Adrian of Cambridge, a peer of England, he often attended the House of Lords, delivering speeches on a wide range of topics - from lizards to nuclear disarmament.

In 1923, Edgar married Hester Pinsent, a descendant of Scottish philosopher David Hume. They had three children - a son and two daughters. Lord Adrian was a brave man who was passionate about fast car driving and mountaineering in his youth. He passed away in 1977.

Edgar was a member of over 40 scientific and professional organizations. He received numerous awards, including the Royal Medal (1934) and the Copley Medal (1946) from the Royal Society, the Gold Medal of the Royal Society of Arts (1953), the Distinguished Service Award from the British Medical Association (1958), and the Jeffcott Medal from the Royal Medical Society (1968).