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David H. Hubel

 
Scientist: David Hunter Hubel
 

Canadian–American neurophysiologist (1926–)

Born in Windsor, Ontario, Hubel was educated at McGill University and then worked at the Montreal Neurological Institute. He moved to America in 1954 and after working at Johns Hopkins joined the Harvard Medical School in 1959 where he was appointed professor of neurobiology from 1968 to 1982.

Beginning in the 1960s, Hubel, in collaboration with the Swedish neurophysiologist Torsten Wiesel (1924––sp;–sp;), published a number of remarkable papers that explained for the first time the mechanism of visual perception at the cortical level.

Their work was made possible by a number of technical advances. From the early 1950s onward it became possible to use microelectrodes to monitor the activity of a single neuron. Further, the work of Louis Sokoloff allowed workers to identify precise areas of neural activity. Using this latter technique it was thus possible to identify the region known as the striate cortex, located at the back of the cortex in the occipital lobes, as one of the key centers of activity during the visual process.

The cells of the striate cortex seemed to be arranged into columns, or ‘hypercolumns’ as they were soon described, that run the length of the cortex (3–4 millimeters) from the outer surface to the underlying white matter. Such hypercolumns were further clearly divided into distinct layers. Hubel and Weisel went on to probe the structure, function, and contents of such columns in great detail.

Above all they succeeded in establishing two crucial points. First that the retinal image was mapped in some way on to the striate cortex. That is, to each point on the retina there corresponded a group of cells in the striate cortex that would respond to a stimulation of that point and of no other.

Furthermore, the response could be evoked only by a relatively precise stimulus. Thus there were cells that would respond to a spot of light but not to a line. Cells that responded to lines would do so only to those lines with a specific tilt and if the angle of tilt was changed by as little as 10°, in either direction, the cells' ability to react would be diminished or even abolished.

As a result of such work the visual cortex has become the best known of all cortical regions. Hubel and Wiesel shared the 1981 Nobel Prize for physiology or medicine with Roger Sperry.

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(born Feb. 27, 1926, Windsor, Ont., Can.) Canadian-born U.S. neurobiologist. He studied medicine at McGill University and in 1959 joined the faculty of Harvard Medical School. In 1981 he shared a Nobel Prize with Torsten Wiesel and Roger Sperry for investigations of visual perception, one of their achievements being analysis of the flow of nerve impulses from the retina to the brain's sensory and motor centres.

For more information on David Hunter Hubel, visit Britannica.com.

 
Columbia Encyclopedia: David Hunter Hubel
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Hubel, David Hunter (hyū'bəl) , 1926–, American neurobiologist, b. Ont., Canada. In 1958, Hubel joined Torsten Wiesel at Johns Hopkins, and the two relocated to Harvard in 1959. Their most famous studies were in the area of visual perception, with particular emphasis on the nerve impulses mediating between the retina and the brain. They observed that various nerve cells were responsible for different types of visual stimuli. In 1981, Hubel and Wiesel received a Nobel prize for their research in neurophysiology.
 
Wikipedia: David H. Hubel
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David H. Hubel
David H. Hubel
David H. Hubel
Born February 27, 1926 (1926-02-27) (age 83)
Windsor, Ontario
Nationality Canada, USA
Fields Neurophysiologist
Known for Visual system
Notable awards Nobel Prize in Physiology or Medicine(1981)

David Hunter Hubel (born February 27, 1926) was co-recipient with Torsten Wiesel of the 1981 Nobel Prize in Physiology or Medicine, for their discoveries concerning information processing in the visual system; the prize was shared with Roger W. Sperry for his independent research on the cerebral hemispheres. In 1978, Hubel and Wiesel were awarded the Louisa Gross Horwitz Prize from Columbia University.

Contents

Research

The Hubel and Wiesel experiments greatly expanded the scientific knowledge of sensory processing. In one experiment, done in 1959, they inserted a microelectrode into the primary visual cortex of an anesthetized cat. They then projected patterns of light and dark on a screen in front of the cat. They found that some neurons fired rapidly when presented with lines at one angle, while others responded best to another angle. Some of these neurons responded differently to light patterns than to dark patterns. Hubel and Wiesel called these neurons "simple cells." Still other neurons, which they termed "complex cells," had identical responses to light and dark patterns. These studies showed how the visual system constructs complex representations of visual information from simple stimulus features (Goldstein, 2001).

Hubel and Wiesel received the Nobel Prize for two major contributions: 1. their work on development of the visual system, which involved a description of ocular dominance columns in the 1960s and 1970s; and 2. their work establishing a foundation for visual neurophysiology, describing how signals from the eye are processed by the brain to generate edge detectors, motion detectors, stereoscopic depth detectors and color detectors, building blocks of the visual scene. By depriving kittens from using one eye, they showed that columns in the primary visual cortex receiving inputs from the other eye took over the areas that would normally receive input from the deprived eye. This has important implications for the understanding of deprivation amblyopia, a type of visual loss due to unilateral visual deprivation during the so-called "critical period". These kittens also did not develop areas receiving input from both eyes, a feature needed for binocular vision. Hubel and Wiesel's experiments showed that the ocular dominance develops irreversibly early in childhood development. These studies opened the door for the understanding and treatment of childhood cataracts and strabismus. They were also important in the study of cortical plasticity (Goldstein, 2001). Furthermore, the understanding of sensory processing in animals served as inspiration for the SIFT descriptor (Lowe, 1999), which is a local feature used in computer vision for tasks such as object recognition and wide-baseline matching, etc. The SIFT descriptor is arguably the most widely used feature type for these tasks.

Biography

Hubel was born in Windsor, Ontario to American parents in 1926. His paternal grandfather emigrated as a child to the U.S.A. from the Bavarian town of Nördlingen. In 1929, his family moved to Montreal where he spent his formative years. From age six to eighteen, he attended Strathcona Academy in Outremont, Quebec about which he said, "[I owe] much to the excellent teachers there, especially to Julia Bradshaw, a dedicated, vivacious history teacher with a memorable Irish temper, who awakened me to the possibility of learning how to write readable English." He studied mathematics and physics at McGill University, and then entered medical school there. In 1954, he moved to the United States to work at Johns Hopkins University, but was drafted by the army and served at Walter Reed Hospital. There, he began recording from the primary visual cortex of sleeping and awake cats. At Walter Reed, he invented the modern metal microelectrode out of Stoner-Mudge lacquer and tungsten, and the modern hydraulic microdrive, for which he had to learn rudimentary machinists skills to produce. In 1958, he moved to Johns Hopkins and began his collaborations with Wiesel, and discovered orientation selectivity and columnar organization in visual cortex. One year later, he joined the faculty of Harvard University.

See also

References

  • Goldstein, B. 2001. Sensation and Perception, 6th ed. London: Wadsworth.

External links


 
 

 

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Scientist. A Dictionary of Scientists. Copyright © Market House Books Ltd 1993, 1999, 2003. All rights reserved.  Read more
Britannica Concise Encyclopedia. Britannica Concise Encyclopedia. © 2006 Encyclopædia Britannica, Inc. All rights reserved.  Read more
Columbia Encyclopedia. The Columbia Electronic Encyclopedia, Sixth Edition Copyright © 2003, Columbia University Press. Licensed from Columbia University Press. All rights reserved. www.cc.columbia.edu/cu/cup/  Read more
Wikipedia. This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "David H. Hubel" Read more