Tactile discrimination activates the visual cortex of the recently blind naive to Braille: a functional magnetic resonance imaging study in humans.
The occipital cortex of blind subjects is known to be activated during tactile discrimination tasks such as Braille reading. To investigate whether this is due to long-term learning of Braille or to sensory deafferentation, we used fMRI to study tactile discrimination tasks in subjects who had recently lost their sight and never learned Braille. The occipital cortex of the blind subjects without Braille training was activated during the tactile discrimination task, whereas that of control sighted subjects was not. This finding suggests that the activation of the visual cortex of the blind during performance of a tactile discrimination task may be due to sensory deafferentation, wherein a competitive imbalance favors the tactile over the visual modality.
Sadato
Norihiro
N
National Institute for Physiological Sciences, 38 Nishigonaka, Myodaiji, Okazaki, 444-8585, Japan. sadato@nips.jp
Okada
Tomohisa
T
Kubota
Kiyokazu
K
Yonekura
Yoshiharu
Y
D000328:Adult; D001766:Blindness / Q000503:physiopathology*; D004192:Discrimination, Psychological / Q000502:physiology*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D012682:Sensory Aids; D014110:Touch / Q000502:physiology*; D014793:Visual Cortex / Q000502:physiology*