Hearing-specialized brain regions adapt to visual input© Amee J. McMillanA new study of deaf cats may help explain why some deaf people have great vision. In hearing cats (left), visual information is processed in one place (yellow) and sound information is processed somewhere else (orange), but in deaf cats, parts of the auditory regions become visual (small yellow areas).
Some deaf people have extraordinarily keen vision, and a new study of cats may explain why. The results, published online October 12 in
Nature Neuroscience, show how parts of the brain normally dedicated to a sense that has been lost can pitch in to augment another type of input.
For years, researchers have known that deaf people often have superior peripheral vision and motion detection, but just how the brain creates these advantages was unclear. "Over the years, we've speculated about how these changes might be taking place," says neuroscientist Helen Neville of the University of Oregon in Eugene, but a clear cause has been elusive.
In the new study, researchers led by Stephen Lomber found that in deaf cats, brain regions important for hearing get co-opted to enhance vision. Instead of processing sound, these regions lend a hand to the visual system. For the first time, the study establishes a causal link between particular auditory regions and vision enhancements.