BöLköLs (Bekesy), Georg( Hungarian-American physicist, Nobel Prize in Physiology or Medicine, 1961)
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Biography BöLköLs (Bekesy), Georg
June 3, 1899, Mr.. - June 13, 1972
Hungarian-American physicist Georg von Bekesy was born in Budapest, the son of Alexander von Bekesy, diplomat, and Paula Bekesy (IASA). Through the diplomatic activity of his father B. able to obtain a truly broad education in schools in Budapest, Munich, Constantinople and Zurich. As a child having a good musical ability, B. wanted to become a concert pianist, but then chose a career scientist. In 1916, Mr.. he entered the University of Bern in Switzerland, and after some hesitation, chose to study physics. After the Hungarian revolution of 1918. B. returned to his homeland, as he later wrote, 'to participate in the construction of the new Hungary'. After serving for a short time in the army, he enrolled at the Budapest University and in 1923 he defended at the University doctoral thesis on issues of hydrodynamics. After that he enrolled in the research laboratory of the Hungarian Ministry of Communications, which was engaged in perfecting just installed the Hungarian telephone network.
. Due to the fact that some European telephone lines to pass through Hungary, in violation of the Hungarian telephone network caused complaints from other countries
. Therefore, one of the first orders B. was to determine which of the three blocks of the network - microphones, transmission lines or telephones - the most in need of improvement. In preliminary studies B. found that the weak link is the membrane of telephones that are heavily distorted sound vibrations, in contrast to the eardrum of the ear. Therefore B. began to investigate in detail the physical properties of the hearing.
When sound waves enter the auricle and external auditory canal, they get on the eardrum and cause its fluctuations. These vibrations through the auditory bones of the middle ear, acting like levers, are transmitted to cochlea - a spiral tube, located in a liquid-filled cavity of the inner ear. Throughout its length snail partitioned main diaphragm of the membrane is the so-called Organ of Corti, including the specialized hair cells. In the main oscillations of the membrane, these cells are excited and transmit signals to the auditory nerve fibers. By the mid 20-ies. anatomy of the inner ear has already been well studied, . and, . as he wrote later, B., . challenge the researcher basically boiled down to, . to solve a mechanical problem: how to vibrate the primary membrane by the action of the eardrum sound davleniyaN If the statement of the problem was a matter of relatively simple, . a statement of specific experiments was considerably more difficult,
. Snail rights - it is very little education (at the widest point of its cross-section of less than one centimeter), and, moreover, it is in the broadest part of the skull. Furthermore, as later recalled B., 'in those days it was generally accepted that the mechanical properties of the tissues of the ear after the death of rapidly changing, and therefore virtually impossible to study these properties of the inner ear'. One of the first achievements of B. was that it showed: These post-mortem changes are mainly due to dehydration, so the structure of the ear, taken from the corpses, you can successfully learn, if they remain, as in life, in a wet environment. Since many of their experiments B. placed on small laboratory animals like guinea pigs, . snail, which is less than, . than humans, . he had to develop new surgical tools and techniques for access, . study, . manipulation and recording the activity of various components of the inner ear.,
. This allowed B
. investigate the movement of the main membrane. In those days there were four theories to explain the perception of the ear, the sounds of different heights. According to one, . the sound of a certain height can cause fluctuations in a restricted area of the membrane, the second alleged, . the sound is a wave, . running along the length of the membrane, in accordance with the third theory, the sound is reflected from the end of the cochlea and forms a standing wave, and finally, . fourth read, . that the membrane oscillates as a whole,
. Subsequently B. wrote: "Although the scientific benefits greater emphasis on the differences between these four theories, I decided to approach the problem from the other side and understand what exactly they have in common '. B. developed a model membrane made of rubber and showed that by changing its thickness, can achieve any type of hesitation from those who predicted each theory. From this he concluded that in order to determine which of the four theories correctly describes the activities of the inner ear, it is necessary to measure its three-dimensional elasticity. His experiments showed that the oscillations of the membrane occurs by type traveling wave.
Main heterogeneous membrane, at the base (closer to the middle ear), it is thinner and more stretched, and at the top - thicker and more 'sags'. A wave of certain frequency, running on the cochlea, causing fluctuations in all parts of the membrane, but one of them to vibrate more rest. The location of this site depends on the frequency of the sound: if the sound is above, it is located closer to the middle ear, and if lower - closer to the top. In the auditory nerve fibers, emitted from the cochlea, the brain receives information about the localization of the maximum vibrating area and on this basis, recognize the sounds of different heights.
All of these studies B. were conducted in the laboratory of the Hungarian Ministry of Communications, where he worked all of the 30-ies. In 1939, Mr.. he was appointed professor of experimental physics at Budapest University, but continued to work in the laboratory of the Ministry of Communications. At the end of World War II, Budapest suffered from the bombing of the Allied air forces and was badly damaged, and in 1946. B. He emigrated to continue his studies at the Swedish Karolinska Institute. Having worked here for years, he went to the United States and enrolled in psychoacoustics lab at Harvard University.
The Harvard B. continued study of the basic biomechanical properties of the inner ear. Received in this regard with sufficient information, he developed an expanded model of the cochlea. This model consisted of a liquid-filled plastic tube containing a membrane length of 30 centimeters, when using the piston caused fluctuations in the liquid at one end of the tube, the membrane extended traveling waves. Instead of Corti's organ, containing the receptor apparatus of the auditory analyzer, B. used his own hand, which he put on the tube. 'While traveling wave propagates along the entire length of the membrane with almost the same amplitude, - wrote B., - I thought that vibrates only section of the membrane length of 2 ... 3 cm'. B. felt only the peak of a traveling wave, which, as the frequency of sound vibrations shifted along the cochlea. 'The simple fact that though the model fluctuations capture the whole hand, but only a small part of it seems vibrant, proves that the nerve inhibition must play an important role in the perception of sound' - concluded B. This conclusion is confirmed his previous ideas about the mechanism of the ear analysis of the frequency of sound vibrations. Such a mechanism could operate in the Corti's organ, in favor of this hypothesis and data by David Hubel and Torsten Vizela, . subsequently showed the example of the visual analyzer, . that inhibition around the most sensitive area of the excited widespread in the human nervous system.,
. By the end of the 50-ies
. B. recreated a complete picture of the biomechanics of the cochlea, which has led to significant progress in diagnosis and treatment of hearing impairment. Through the work of B. modern otohirurgi were able to implant the artificial ear drums made of skin or veins, and even replace the small hearing bones with plastic prostheses.
In 1961. B. was awarded the Nobel Prize in Physiology or Medicine "for his discovery of the physical mechanisms of perception of stimulation snail '. In his welcome speech, a researcher at the Karolinska Institute Carl Gustaf Bernhard said: 'B. equipped us with knowledge of the physical processes occurring in all key areas of sound transmission in the ear '. Furthermore, he added, 'the opening of B. made a vital contribution to the analysis of the relationship between mechanical and electrical phenomena in the receptors responsible for conversion of sound into nerve impulses. "
In 1966, Mr.. B. became a professor at the University of Hawaii, where he worked until the end of life. Being engaged in the study of the auditory analyzer, he became interested in the laws common to all kinds of sensitivity, particularly to touch and taste.
B. his life remained a bachelor, his passion was art. An avid art collector, especially the eastern, he bequeathed his entire collection of the Nobel Foundation. Died B. in 1972
In addition to the Nobel Prize, B. was awarded the medal Leibniz Germanskoy Academy of Sciences (1937), the Academic Prize of the Hungarian Academy of Sciences (1946) and the Howard Crosby Warren medal of the American Society experimental psychologists (1955). He was a member of the U.S. National Academy of Sciences and had honorary degrees from the University of William and the University of Berne.