New insight into how blind people 'see with sound'

Posted Mar 15, 2014 by Tim Sandle
New research shows how, by converting sights to sounds, the brains of congenitally blind people respond similarly to various objects in a similar way to people who can see.
It has been long established that the brains of people blind from a young age compensate for the lack of visual input by putting more emphasis on the other senses. A new insight has been provided in the way that sounds help blind people to "see."
In a new study, blind participants used an augmented reality system that converts images into sounds. It was found that the brains of blind and sighted people sometimes react to similar objects in much the same way, despite vastly different sensory inputs. Augmented reality (AR) is a live, copy, view of a physical, real-world environment whose elements are augmented (or supplemented) by computer-generated sensory input such as sound, video, graphics or GPS data
Scanning the brains of blind and sighted people presented with different objects in this system, researchers at the Hebrew University of Jerusalem found that in response to the outline or silhouette of a human body, the cerebral cortex became active in both blind and sighted people. And in both blind and sighted subjects, human body shapes also elicited activation in a brain region called the temporal-parietal junction, which may be involved in determining the intentions of others.
The augmented reality system allowed blind people to accurately classify 78 percent of objects they were presented in one of three groups: people, everyday objects, or textured patterns. Moreover, the soundscapes emitted by the system also portrayed information about a person’s position, for example, among other details.
Lead researcher Ella Striem-Amit told Science Now "The brain, it turns out, is a task machine, not a sensory machine. You get areas that process body shapes with whatever input you give them—the visual cortex doesn’t just process visual information."
The research has been published in the journal Current Biology, in a paper titled "Visual Cortex Extrastriate Body-Selective Area Activation in Congenitally Blind People “Seeing” by Using Sounds."