Adrian Edgar( English physiologist, Nobel Prize in Physiology or Medicine, 1932)
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Biography Adrian Edgar
November 30, 1889, Mr.. - August 4, 1977
English physiologist Edgar Douglas Adrian was born in London. His parents were Alfred Douglas Adrian, Legal Adviser, Adrian and Flora Lavinia (Burton). The family had three children, Edgar was a middle-age. In 1908, Mr.. Edgar graduated from the prestigious high school in Westminster and enrolled at Trinity College at Cambridge University to study natural sciences. Here he worked under the guidance of physiologist Keith Lucas, who studied the reactions of nerves and muscles to electrical stimulation. Soon, Edgar joined in this work.
In 1871, Mr.. it was found that the reaction of the heart muscle to electric effect obeys the 'all or nothing' - either this response is maximal or not occur at all. In 1905, Mr.. Lucas found that not only the heart, but also for any other special characteristic of muscle response due to variations in the number of excited fibers and reduce the frequency of their. Although in subsequent experiments, Lucas received significant data in favor of, . that nerves characteristic reaction, . obey the law 'all or nothing', . direct evidence of this was, . since then there was no way of registration activity of single nerve cells.,
. In his works, E
. and Lucas studied, . is whether the energy of the stimulus energy source for the spread of the nerve impulse (action potential), . just as it does when flying bullets, . or whether this process is self-sustaining reaction - such as the spread of flame on a wick,
. Their data showed the benefit of the second assumption. However, only in 40-ies. Alan Hodgkin and Andrew Huxley revealed the mechanism of the action potential.
In 1911, Mr.. E. graduated from Cambridge University and two years later became a Fellow of Trinity colleges, Ms.. By this time he came to the conclusion that the knowledge of medicine will help him in scientific work, and shortly before the First World War began working in a London hospital of St.. Bartholomew. In record time - a little more than a year - E. was practicing medicine. The war years he spent in England, studying and treating concussions and neurological lesions.
Until his death, Lucas, who died in a plane crash in 1961, they E. discussed possible ways of recording the electrical activity of single nerve fibers, by the time it was known that the duration of these pulses is only a few thousandths of a second, and the value of them - the order of several microvolts. All this is not possible to register such pulses using existing equipment while. Lucas proposed to try to record electrical signals from nerves, using them to enhance thermionic lamps such as those that have been invented by Guglielmo Marconi, Ferdinand and Brown.
. Since after the war has sharply increased flow of students and E
. had to devote much time to teaching, the idea of Lucas several years failed to implement. However, although scientific activity for E. and moved to second place, he made several important observations concerning the period of refractoriness of nerves and muscles (ie. period of time immediately after the electric pulse, when the excitable tissue), and in 1922. with the American neuroscientists Alexander Forbes has received strong evidence in favor of the fact that the sensory nerves, as well as motor, obey the law 'all or nothing'. This discovery was unexpected, because at that time, most scientists believed that the information coming from sensory nerves, too complicated and can not be coded as simple pulses.
In 1925, Mr.. E. was used in their experiments, tube amps. By the time Herbert Gasser and his colleagues from medical school at Johns Hopkins have created a power with which it became possible to record action potentials in bundles of motor nerve fibers. E. constructed under the scheme Gasser its own power and tested it in experiments on the nerves innervating the muscles of the frog. Earlier, Charles Sherrington suggested that from the muscles are sensitive nerves perceive stretching these muscles. E. able to make such a piece of muscle, which contained only one sensitive receptor; tensile muscles, this receptor was excited. It turned out that all the impulses in the nerve of this receptor have the exact same duration and amplitude, but, as he wrote E. later, 'frequency (pulses) depends on the degree and speed of stretching, ie. the degree of excitation of sensory organ. In connection with this impulse is much more information than just a signal that the excitement has happened '.
In the next few years, E. and his colleagues studied the pulsation in the various sensory and motor nerves, and their findings were the basis for a general theory of sensitivity. In accordance with the representations of E. sensitive human receptors only respond to environmental change, and after the change occurred, adapting to new situations. From the intensity of excitation of receptors depends on the frequency of impulses in the sensory nerves.
Subsequently, E. described the entire process, from the excitation of receptors to the perception of his brain. He wrote: 'Excitation of receptors gradually decreases, and the extent of this decline intervals between impulses in the sensory fibers are becoming more. These pulses are integrated by means of some central processes, and thereby increase and decrease of sensation is a fairly exact copy of the rise and decay of excitation of receptors. As for the nature of sensation, it obviously depends on the path along which the impulses'. In other words, all the impulses in the sensory nerves of the same. Light is perceived as light, . and the sound - the sound is not because, . between the sensitive processes in the organs of vision or hearing, there is no fundamental difference, . and therefore, . that the brain sees any stimulation of the optic nerves as light, . and hearing - as sound.,
. In experiments E
. on the motor nerves, it was found that 'possible variety of signals coming from the motor nerves to the muscles ... limited to the same extent as in the occurrence of impulses in sensory nerves, are also determined by the magnitude of the effect the frequency of impulses and the number of excited fibers'. Discovery of E. on adaptation and coding of nerve impulses allowed the researchers to conduct a full and objective examination of sensation.
In 1932, Mr.. E. together with Sherrington was awarded the Nobel Prize in Physiology or Medicine "for discoveries concerning the functions of nerve cells'. In his speech at the awards ceremony a researcher at the Karolinska Institute Goran Liliestrand said: 'E Portfolio. made a vital contribution to our understanding of the principles of nerve cells and the adaptation of the sense organs'
By the time the interests of E. moved from the peripheral sense organs to the brain. His work on the electrical signals from the brain, carried out in the early 30's. Have become an important contribution to the development of electroencephalography as the method of brain research.
During the next 20 years, E. experimentally studied a variety of objects - the auditory analyzer, . sensory cortex (areas of the brain, . responsible for the processing of complex sensory signals), . cerebellum, . vestibular apparatus, . olfactory organs, perhaps, . All these studies were for him the approaches to solving common problems - to understand the central nervous system as a whole,
. Excellent experimentalist, he often experimented on himself. Thus, once E. injected himself in the shoulder by a long needle and using it within two hours of recorded the activity of their muscles.
In 1951, Mr.. E. left the post of professor of physiology at Cambridge University and head of Trinity College. In this regard, most of the time he had to devote administrative work, lectures and political activities. From 1950 to 1955. E. served as President of the Royal Society of London, of which he was with the 1923. As president of this society, it is during the year was also the president of the British Association for the Advancement of Science, and thus, at the same time led both of these organizations, which was the third occasion in their history.
From 1957 to 1959. E. was Provost of the University of Cambridge, and since 1968. December 1975. - The Principal. Alan Hodgkin recalled that, 'when E. became the rector, the staff of Trinity College, boating, appealed to him to give them the honor to bring his boat up the river from the Trinity College to the University Center. Although E. then it was already 78 years old, he agreed and, in the official garb, he sat behind the wheel and successfully held the boat through a lot of bridges upstream '.
Highest honors in his life E. was awarded in 1955, when Queen Elizabeth II bestowed on him the title of Baron. As Baron Adrian of Cambridge, peer of England, he often visited the House of Lords, giving speeches on various topics - from foot and mouth disease to nuclear disarmament.
In 1923, Mr.. E. married Esther Pinsent, one of the descendants of the Scottish philosopher, David Hume. They had three children - a son and two daughters. Lord E. was a brave man, who was interested in youth-speed ride in a car and mountaineering. He died in 1977
E. was a member of more than 40 scientific and professional organizations. He was awarded many prizes, t. h. Royal medal (1934) and the Copley medal (1946) Royal Society, . Albert Gold Medal of the Royal Society of Arts (1953), . medal for outstanding achievements of the British Medical Association (1958) and medals Dzhefkotta Royal Society of Medicine (1968).,