(July 7, 2012) Lacking
sound input, the primary auditory cortex "feels" touch
People who
are born deaf process the sense of touch differently than people who are born
with normal hearing, according to research funding by the National Institutes
of Health. The finding reveals how the early loss of a sense — in this case
hearing — affects brain development. It adds to a growing list of discoveries
that confirm the impact of experiences and outside influences in molding the
developing brain. The study is published in the July 11 online issue of The
Journal of Neuroscience.
"This research
shows how the brain is capable of rewiring in dramatic ways," said James
F. Battey, Jr., M.D., Ph.D., director of the NIDCD. "This will be of great
interest to other researchers who are studying multisensory processing in the
brain."
The researchers, Christina M. Karns, Ph.D., a postdoctoral
research associate in the Brain Development Lab at the University of Oregon,
Eugene, and her colleagues, show that deaf people use the auditory cortex to
process touch stimuli and visual stimuli to a much greater degree than occurs
in hearing people. The finding suggests that since the developing auditory
cortex of profoundly deaf people is not exposed to sound stimuli, it adapts and
takes on additional sensory processing tasks.