Hubel and Wiesel

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Original contributed by Chris Dyer

David Hubel and Torsten Wiesel received the Nobel Prize in Medicine in 1981 for their work on information processing in and the neurophysiology of the primary visual cortex. Although they tended to avoid direct entanglements with abstract or "higher" level questions about, for example, perception, their results have been of immense interest to philosophers of mind.

A crucial aspect of their work was the exploration of the role that the environment plays in shaping the neural physiology of the visual system and establishing perceptual behaviors. In the primary visual cortex of normal cats (and all sighted mammals), individual neurons show selective responses to differing visual stimuli, such as to particular patterns of motion, lines oriented in a particular way, and so forth. However, by depriving cats of appropriate visual stimuli during their infancy (for example, by suturing a single and both eyes), they demonstrated that the cellular columns that normally would have processed the information from the blinded eye atrophied. If a normal visual environment was restored, the animals failed to develop normal vision even if the deprivation occurred during a certain developmental window, which Hubel and Wiesel refered to as the critical period. Deprivation of visual stimuli after the critical period did not have any effect.

References

  • Hubel, David H. (1981) "Evolution of Ideas on the Primary Visual Cortex, 1955-1978: A Biased Historical Account", Nobel lecture.
  • Wiesel, Torsten N. (1981) "The Postnatal Development of the Visual Cortex and the Influence of the Environment", Nobel lecture.