Tactile perception recruits functionally related visual areas in the late-blind.
When blind people touch Braille characters, blood flow increases in visual areas, leading to speculation that visual circuitry assists tactile discrimination in the blind. We tested this hypothesis in a functional magnetic resonance imaging study designed to reveal activation appropriate to the nature of tactile stimulation. In late-blind individuals, hMT/V5 and fusiform face area activated during visual imagery of moving patterns or faces. When they touched a doll's face, right fusiform face area was again activated. Equally, hMT/V5 was activated when objects moved over the skin. We saw no difference in hMT/V5 or fusiform face area activity during motion or face perception in the congenitally blind. We conclude that specialized visual areas, once established through visual experience, assist equivalent tactile identification tasks years after the onset of blindness.
Goyal
Manu S
MS
Department of Neurology, Washington University School of Medicine, St Louis, Missouri, USA. msgoyal@gmail.com
Hansen
Peter J
PJ
Blakemore
Colin B
CB
D000328:Adult; D001766:Blindness / Q000145:classification / Q000503:physiopathology*; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008875:Middle Aged; D010100:Oxygen / Q000097:blood; D011932:Reading; D012682:Sensory Aids; D013997:Time Factors; D014110:Touch / Q000502:physiology*; D014793:Visual Cortex / Q000098:blood supply / Q000503:physiopathology*; D019987:Persons with Visual Disabilities
D010100:Oxygen