For the first time, researchers have verified that the part of the brain involved in processing the sense of sight is also necessary for the sense of touch. Results of an Emory University study confirming the role of visual cortex in tactile (touch) perception are reported in this week's issue of the journal Nature.
"The findings are relevant to understanding not only how the brain normally processes sensory information, but also how such processing is altered in conditions such as blindness, deafness or numbness and ultimately, to improving methods of communication for individuals afflicted with these disorders," says lead author Krishnankutty (Krish) Sathian, M.D., Ph.D., associate professor of neurology and joint associate professor of rehabilitation medicine at the Emory University School of Medicine and a faculty member in the interdisciplinary Neuroscience Program at Emory University.
Until recently, scientists believed separate brain regions processed information gathered by the various senses. This view is now being challenged.
"The kind of interaction among the senses identified in our work may be more common than generally appreciated," Dr. Sathian says. "Recent findings that visual cortex is active during Braille reading in the blind are perhaps less surprising if viewed in this context."
In one of the tasks used in Dr. Sathian's laboratory, a grooved object is impressed onto the fingertip (grating) of human volunteers. With their eyes closed or blindfolded, the subjects attempt to distinguish, via touch, the orientation of the grooves, i.e., the direction in which the grooves run (along vs. across the finger).
"People who performed this task told us they were visualizing 'with the
mind's eye' the orientation of the grating on the fingertip, suggesting to us
that visual imagery facilitates this tactile task," Dr. Sathian says. "I had
thought for some t
Contact: Sarah Goodwin
Emory University Health Sciences Center