Three Pioneers of the Brain

Mapping the mind wins Nobels for researchers in the U.S.

The human brain is a whole universe, and of all the questions that it can conceive, none is more mysterious or intriguing than precisely how it works. For tracing some of the elusive answers through the intricate corridors of consciousness and perception, three scientists, two American and one Swedish, last week were awarded Nobel Prizes in Medicine. For his pioneering research into the differing functions of the brain's two cerebral hemispheres, Roger Sperry, 68, of the California Institute of Technology, won half of the $181,818 prize. The other half was divided between David Hubel, 55, and Torsten Wiesel, 57, both professors of neurobiology at Harvard Medical School, for discovering how images are transferred from the eye's retina to the brain.

Sperry's research, carried out over three decades, forms the theoretical basis for much of the modern research into how the brain processes information. Previously it was thought that one hemisphere of the brain was dominant, and the other was a minor one that lacked the capacity for higher mental functions. Working first with test animals, Sperry surgically severed the network of hundreds of millions of nerve fibers connecting the two hemispheres. He discovered that the animals could still perform learned tasks when stimulated solely on one hemisphere, but that the other hemisphere could be taught to perform similar tasks, demonstrating that each hemisphere, independently, contained the ability to learn.

Sperry then studied epileptics who had undergone similar surgery to control seizures. Surprisingly, the patients had suffered no obvious changes in mental capacity. Sperry's test procedures proved that each cerebral hemisphere in such patients had its own separate world of consciousness, perceptual experience, emotions, thoughts and memory. In subsequent research, the right hemisphere, far from being inferior to the left, as was once thought, proved clearly superior in some respects, including the capacity for intuitive thinking, interpreting auditory impressions and comprehending spatial relationships. Said the Nobel Committee of Sperry's achievements: "He has provided us with an insight into the inner world of the brain which hitherto had been almost completely hidden from us."

Hubel and Wiesel have provided a road map of a small portion of that world. By measuring electrical impulses given off by the neurons of the visual cortex, the researchers discovered that the cells in the cortex are arranged in a regular pattern in columns organized into equally regular "hypercolumns." Each cell within each column, they discovered, has a specific responsibility to perceive and analyze incoming images according to contrast, linear patterns and movement on the retina. Within the columns, the analysis also occurs in a formal sequence. Eventually all this information is relayed to the higher centers in the brain where the "full picture," or visual impression, is assembled and a memory of it stored.

Later researchers have based much of their work on the theories and techniques devised by Sperry, Hubel and Wiesel, but the workings of the brain remain largely a mystery. Hubel insists the puzzle can be solved. Says he: "We can think differently about the mind now. It is not a mystical thing, but something that can be understood."

This file is automatically generated by a robot program, so viewer discretion is required.