Mouth clicks show how blind can learn to ‘see’ like bats

They make clicking noises with their mouths and listen to the returning echoes to make sense of their environment. A few are so adept that they use it to go mountain biking, play ball games, or explore unknown places.

Surprisingly, the echoes are processed using the visual part of the brain – not the auditory region that receives sound signals from the ears, scientists have discovered.

Researchers in Canada carried out functional magnetic resonance imaging (fMRI) scans to study the brain activity of two blind “echolocators”.

Tiny microphones were placed in the volunteers’ ears to record the clicks they made and pick up their very faint echoes.

Both male participants, one aged 43 and the other 27, were left completely blind in childhood.

Not only could they identify the shape and movement of objects from their echoes, but they focused the associated brain activity in regions that normally process visual information.

The study’s co-author Dr Stephen Anott, from the Rotman Research Institute in Toronto, said: “There is the possibility that even in sighted people who learn to echolocate, visual brain areas might be recruited.”