David H. Hubel

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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.

Contents 1 Research 2 Biography 3 See also 4 References 5 External links

[edit] 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).

[edit] Biography

Hubel was born in Windsor, Ontario to American parents in 1926. 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 math 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.

[edit] See also

Torsten Wiesel

Single Unit Recording

[edit] References

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

[edit] External links

• Nobel Prize Biography
• Eye, Brain, and Vision - online book