A blind man's clicks activate the visual part of his brain, not the auditory one
Daniel Kish, blind from infancy, navigates by making tongue clicks and reading the echoes, a skill called human echolocation. Brain scans of Kish and another expert echolocator showed the incoming echoes activated their visual cortex rather than their auditory cortex, while sighted non-echolocators showed no such activation. Researchers think the brain is repurposing visual processing to build a spatial picture out of sound.