A new study by a team of researchers headed by Dr. Ehud Zohary of the Department of Neurobiology at the Alexander Silberman Institute of Life Sciences at the Hebrew University of Jerusalem provides a better understanding of this phenomenon through closer examination of how and where information is processed in the brains of blind people. An article on his work appears in the current online edition of Nature Neuroscience magazine. It is believed that this work could open a window towards future enhancement of the quality of life for blind people.
Humans, like other primates, rely primarily on vision to direct their behavior. The areas devoted to vision constitute some 25 percent of the human brain. The prevailing thought up to now was that the loss of vision due to blindness renders these regions useless. New evidence, however, shows that the "unemployed" occipital cortex in the brain -- which usually functions in connection with vision -- is utilized in the blind for other purposes.
For example, neuroimaging techniques have shown that the occipital cortex of congenitally blind people is active during Braille reading, indicating that this so-called "sight" region of the brain becomes reoriented for information processing connected with the sense of touch.
Yet, Braille reading involves more than just fine tactile judgments, since reading involves language and memory processes as well. Using functioning imaging (fMRI) in the congenitally blind, Zohary, together with his doctoral students Amir Amedi and Noa Raz, found that extensive regions in the occipital cortex are activated not only during Braille reading, but also during performances of verbal memory tasks, such as recalling a list of abstract words.