Processing of visual information by the brain
The work of Roger W. Sperry, David H. Hubel and Torsten N. Wiesel was awarded a Nobel Prize in 1981.
In the 1950s, Roger W. Sperry began investigating the function of the left and right cerebral hemispheres of the brain. By studying monkeys, he found that the nerves connecting the left and right hemispheres could be severed without causing any drastic changes in the monkeys; each side of the brain was still able to learn, however, what was learned by one side could no longer be retrieved by the other.
In the 1960s Sperry worked with patients who had undergone a similar surgical process to treat their epilepsy. He found that, although structurally identical, the left and right hemispheres play different roles in the brain: the left is responsible for analytical and abstract thought, language and mathematical calculations, while the right side is responsible for spatial awareness and the processing of auditory input.
David H. Hubel and Torsten N. Wiesel used research on cats to learn more about visual processing. By following the path of visual impulses once they had reached the brain’s visual cortex, they found that signals pass systematically through many nerve cells arranged in a series of columns. Each nerve cell processes one small part of the image, until the entire image sent by the retina can be registered as a whole. Importantly, the pair found that the function of the visual cortex cells develops shortly after birth in response to visual stimulation, and that the absence of such stimulation can have long term effects on vision.