This article needs additional citations for verification .(August 2007)
Georg von Békésy
|Died||13 June 1972 73) (aged|
|Awards|| Nobel Prize in Physiology or Medicine (1961)|
ASA Gold Medal (1961)
Georg von Békésy (Hungarian : Békésy György, Hungarian pronunciation: [ˈbeːkeːʃi] ; 3 June 1899 – 13 June 1972) was a Hungarian biophysicist.
By using strobe photography and silver flakes as a marker, he was able to observe that the basilar membrane moves like a surface wave when stimulated by sound. Because of the structure of the cochlea and the basilar membrane, different frequencies of sound cause the maximum amplitudes of the waves to occur at different places on the basilar membrane along the coil of the cochlea.High frequencies cause more vibration at the base of the cochlea while low frequencies create more vibration at the apex.
He concluded that his observations showed how different sound wave frequencies are locally dispersed before exciting different nerve fibers that lead from the cochlea to the brain.
In 1961, he was awarded the Nobel Prize in Physiology or Medicine for his research on the function of the cochlea in the mammalian hearing organ.
Békésy was born on 3 June 1899 in Budapest, Hungary, as the first of three children (György 1899, Lola 1901 and Miklós 1903) to Alexander von Békésy (1860–1923), an economic diplomat born in Kolozsvár, Austria-Hungary (now Cluj-Napoca, Romania), and to his mother Paula Mazaly.
The Békésy family was originally Reformed but converted to Catholicism.His mother, Paula (1877–1974) was born in Čađavica, Austria-Hungary (now Croatia). His maternal grandfather was from Pécs.
Békésy went to school in Budapest, Munich, and Zürich. He studied chemistry in Bern and received his PhD in physics on the subject: "Fast way of determining molecular weight" from the University of Budapest in 1926.
He then spent one year working in an engineering firm. He published his first paper on the pattern of vibrations of the inner ear in 1928. He was offered a position at Uppsala University by Róbert Bárány, which he declined because of the hard Swedish winters.
Before and during World War II, Békésy worked for the Hungarian Post Office (1923 to 1946), where he did research on telecommunications signal quality. This research led him to become interested in the workings of the ear. In 1946, he left Hungary to follow this line of research at the Karolinska Institute in Sweden.
In 1947, he moved to the United States, working at Harvard University until 1966. In 1962 he was elected a Member of the German Academy of Sciences Leopoldina.After his lab was destroyed by fire in 1965, he was invited to lead a research laboratory of sense organs in Honolulu, Hawaii. He became a professor at the University of Hawaii in 1966 and died in Honolulu.
He became a well-known expert in Asian art. He had a large collection which he donated to the Nobel Foundation in Sweden. His brother, Dr. Miklós Békésy (1903-1980), stayed in Hungary and became a famous agrobiologist who was awarded the Kossuth Prize.
Békésy contributed most notably to our understanding of the mechanism by which sound frequencies are registered in the inner ear. He developed a method for dissecting the inner ear of human cadavers while leaving the cochlea partly intact. By using strobe photography and silver flakes as a marker, he was able to observe that the basilar membrane moves like a surface wave when stimulated by sound. Because of the structure of the cochlea and the basilar membrane, different frequencies of sound cause the maximum amplitudes of the waves to occur at different places on the basilar membrane along the coil of the cochlea.High frequencies cause more vibration at the base of the cochlea while low frequencies create more vibration at the apex.
Békésy concluded from these observations that by exciting different locations on the basilar membrane different sound wave frequencies excite different nerve fibers that lead from the cochlea to the brain. He theorized that, due to its placement along the cochlea, each sensory cell (hair cell) responds maximally to a specific frequency of sound (the so-called tonotopy). Békésy later developed a mechanical model of the cochlea, which confirmed the concept of frequency dispersion by the basilar membrane in the mammalian cochlea.
In an article published posthumously in 1974, Békésy reviewed progress in the field, remarking "In time, I came to the conclusion that the dehydrated cats and the application of Fourier analysis to hearing problems became more and more a handicap for research in hearing,"referring to the difficulties in getting animal preparations to behave as when alive, and the misleading common interpretations of Fourier analysis in hearing research.
(Budapest, 1899 –
Honolulu, 1972 )
Sándor Békésy (Kolozsvár, 1860 –
Budapest, 1923) (Calvinist)
(Debrecen, 1822 – Kolozsvár 1898)
Péter Békésy (Debrecen)
Debrecen 18... – Debrecen, 18...) (Calvinist)
apáczai Julia Szabó (Kolozsvár 1833 –
Kolozsvár, 1897) (Calvinist)
apáczai János Szabó
(Kolozsvár 18... – 18...) (Calvinist)
(Čađavica [ circular reference ]1877 – Budapest 1974) (Roman Catholic)
József Mazaly (Pécs, 1838 -
(x, 17... –
(17... – 18..) (Roman Catholic)
Alojzia Adler (Pécs, 1844 24/02. –
x, 1897) (Roman Catholic)
Julianna Thoma (Roman Catholic)
Békésy's honours include:
The inner ear is the innermost part of the vertebrate ear. In vertebrates, the inner ear is mainly responsible for sound detection and balance. In mammals, it consists of the bony labyrinth, a hollow cavity in the temporal bone of the skull with a system of passages comprising two main functional parts:
The cochlea is the part of the inner ear involved in hearing. It is a spiral-shaped cavity in the bony labyrinth, in humans making 2.75 turns around its axis, the modiolus. A core component of the cochlea is the Organ of Corti, the sensory organ of hearing, which is distributed along the partition separating the fluid chambers in the coiled tapered tube of the cochlea.
The basilar membrane is a stiff structural element within the cochlea of the inner ear which separates two liquid-filled tubes that run along the coil of the cochlea, the scala media and the scala tympani. The basilar membrane moves up and down in response to incoming sound waves, which are converted to traveling waves on the basilar membrane.
The organ of Corti, or spiral organ, is the receptor organ for hearing and is located in the mammalian cochlea. This highly varied strip of epithelial cells allows for transduction of auditory signals into nerve impulses' action potential. Transduction occurs through vibrations of structures in the inner ear causing displacement of cochlear fluid and movement of hair cells at the organ of Corti to produce electrochemical signals.
In physiology, sensory transduction is the conversion of a sensory stimulus from one form to another. Transduction in the nervous system typically refers to stimulus-alerting events wherein a physical stimulus is converted into an action potential, which is transmitted along axons towards the central nervous system for integration. It is a step in the larger process of sensory processing.
The auditory system is the sensory system for the sense of hearing. It includes both the sensory organs and the auditory parts of the sensory system.
The ear is the organ that enables hearing and, in mammals, balance. In mammals, the ear is usually described as having three parts—the outer ear, the middle ear and the inner ear. The outer ear consists of the pinna and the ear canal. Since the outer ear is the only visible portion of the ear in most animals, the word "ear" often refers to the external part alone. The middle ear includes the tympanic cavity and the three ossicles. The inner ear sits in the bony labyrinth, and contains structures which are key to several senses: the semicircular canals, which enable balance and eye tracking when moving; the utricle and saccule, which enable balance when stationary; and the cochlea, which enables hearing. The ears of vertebrates are placed somewhat symmetrically on either side of the head, an arrangement that aids sound localisation.
The acoustic reflex is an involuntary muscle contraction that occurs in the middle ear in response to loud sound stimuli or when the person starts to vocalize.
Sensorineural hearing loss (SNHL) is a type of hearing loss in which the root cause lies in the inner ear or sensory organ or the vestibulocochlear nerve. SNHL accounts for about 90% of reported hearing loss. SNHL is usually permanent and can be mild, moderate, severe, profound, or total. Various other descriptors can be used depending on the shape of the audiogram, such as high frequency, low frequency, U-shaped, notched, peaked, or flat.
In physiology, tonotopy is the spatial arrangement of where sounds of different frequency are processed in the brain. Tones close to each other in terms of frequency are represented in topologically neighbouring regions in the brain. Tonotopic maps are a particular case of topographic organization, similar to retinotopy in the visual system.
The Weber test is a screening test for hearing performed with a tuning fork. It can detect unilateral (one-sided) conductive hearing loss and unilateral sensorineural hearing loss. The test is named after Ernst Heinrich Weber (1795–1878). Conductive hearing ability is mediated by the middle ear composed of the ossicles: the malleus, the incus, and the stapes. Sensorineural hearing ability is mediated by the inner ear composed of the cochlea with its internal basilar membrane and attached cochlear nerve. The outer ear consisting of the pinna, ear canal, and ear drum or tympanic membrane transmits sounds to the middle ear but does not contribute to the conduction or sensorineural hearing ability save for hearing transmissions limited by cerumen impaction.
In audiology and psychoacoustics the concept of critical bands, introduced by Harvey Fletcher in 1933 and refined in 1940, describes the frequency bandwidth of the "auditory filter" created by the cochlea, the sense organ of hearing within the inner ear. Roughly, the critical band is the band of audio frequencies within which a second tone will interfere with the perception of the first tone by auditory masking.
Volley theory states that groups of neurons of the auditory system respond to a sound by firing action potentials slightly out of phase with one another so that when combined, a greater frequency of sound can be encoded and sent to the brain to be analyzed. The theory was proposed by Ernest Wever and Charles Bray in 1930 as a supplement to the frequency theory of hearing. It was later discovered that this only occurs in response to sounds that are about 500 Hz to 5000 Hz.
The round window is one of the two openings from the middle ear into the inner ear. It is sealed by the secondary tympanic membrane, which vibrates with opposite phase to vibrations entering the inner ear through the oval window. It allows fluid in the cochlea to move, which in turn ensures that hair cells of the basilar membrane will be stimulated and that audition will occur.
The Greenwood function correlates the position of the hair cells in the inner ear to the frequencies that stimulate their corresponding auditory neurons. Empirically derived in 1961 by Donald D. Greenwood, the relationship has shown to be constant throughout mammalian species when scaled to the appropriate cochlear spiral lengths and audible frequency ranges. Moreover, the Greenwood function provides the mathematical basis for cochlear implant surgical electrode array placement within the cochlea.
The tectoria membrane (TM) is one of two acellular membranes in the cochlea of the inner ear, the other being the basilar membrane (BM). "Tectorial" in anatomy means forming a cover. The TM is located above the spiral limbus and the spiral organ of Corti and extends along the longitudinal length of the cochlea parallel to the BM. Radially the TM is divided into three zones, the limbal, middle and marginal zones. Of these the limbal zone is the thinnest (transversally) and overlies the auditory teeth of Huschke with its inside edge attached to the spiral limbus. The marginal zone is the thickest (transversally) and is divided from the middle zone by Hensen's Stripe. It overlies the sensory inner hair cells and electrically-motile outer hair cells of the organ of Corti and during acoustic stimulation stimulates the inner hair cells through fluid coupling, and the outer hair cells via direct connection to their tallest stereocilia.
An analog ear or analog cochlea is a model of the ear or of the cochlea based on an electrical, electronic or mechanical analog. An analog ear is commonly described as an interconnection of electrical elements such as resistors, capacitors, and inductors; sometimes transformers and active amplifiers are included.
The cochlear amplifier is a positive feedback mechanism within the cochlea that provides acute sensitivity in the mammalian auditory system. The main component of the cochlear amplifier is the outer hair cell (OHC) which increases the amplitude and frequency selectivity of sound vibrations using electromechanical feedback.
Electrocochleography is a technique of recording electrical potentials generated in the inner ear and auditory nerve in response to sound stimulation, using an electrode placed in the ear canal or tympanic membrane. The test is performed by an otologist or audiologist with specialized training, and is used for detection of elevated inner ear pressure or for the testing and monitoring of inner ear and auditory nerve function during surgery.
Bone-conduction auditory brainstem response or BCABR is a type of auditory evoked response that records neural response from EEG with stimulus transmitted through bone conduction.
|Wikiquote has quotations related to: Georg von Békésy|