By Devin Powell
SEATTLE — About a year and a half after her stroke, a 36-year-old professor started to feel sounds. A radio announcer’s voice made her tingle. Background noise in a plane felt physically uncomfortable.
Now Tony Ro, a neuroscientist at the City College of New York and the Graduate Center of the City University of New York, might have figured out the cause of this synesthesia. Sophisticated imaging of the woman’s brain revealed that new links had grown between its auditory part, which processes sound, and the somatosensory region, which handles touch.
“The auditory area of her brain started taking over the somatosensory area,” says Ro, who used diffusion tensor imaging, which focuses on the brain’s white matter connections, to spot the change.
This connection between sound and touch may run deep in the rest of us as well, Ro and colleagues said during presentations May 25 at a meeting of the Acoustical Society of America. Both hearing and touch, the scientists pointed out, rely on nerves set atwitter by vibration. A cell phone set to vibrate can be sensed by the skin of the hand, and the phone’s ring tone generates sound waves — vibrations of air — that move the eardrum.