BRAIN MECHANISM UNDERLYING RECOGNITION OF HAND GESTURES DEVELOPS EVEN WHEN BLIND
Does a distinctive
mechanism work in the brain of congenitally blind individuals when
understanding and learning others' gestures? Or does the same mechanism as with
sighted individuals work? Japanese researchers figured out that activated brain
regions of congenitally blind individuals and activated brain regions of
sighted individuals share common regions when recognizing human hand gestures.
They indicated that a region of the neural network that recognizes others' hand
gestures is formed in the same way even without visual information.
The findings are
discussed in The Journal of Neuroscience.
Our brain mechanism
perceives human bodies from inanimate objects and shows a particular response.
A part of a region of the "visual cortex" that processes visual
information supports this mechanism. Since visual information is largely used
in perception, this is reasonable, however, for perception using haptic
information and also for the recognition of one's own gestures, it has been
recently learned that the same brain region is activated. It came to be
considered that there is a mechanism that is formed regardless of the sensory
modalities and recognizes human bodies.
Blind and sighted
individuals participated in the study of the research group of Assistant
Professor Ryo Kitada of the National Institute for Physiological Sciences,
National Institutes of Natural Sciences. With their eyes closed, they were
instructed to touch plastic casts of hands, teapots, and toy cars and identify
the shape. As it turned out, sighted individuals and blind individuals could
make an identification with the same accuracy. Through measuring the activated
brain region using functional magnetic resonance imaging (fMRI), for plastic
casts of hands and not for teapots or toy cars, the research group was able to
pinpoint a common activated brain region regardless of visual experience. On
another front, it also revealed a region showing signs of activity that is
dependent on the duration of the visual experience and it was also learned that
this region functions as a supplement when recognizing hand gestures.
As Assistant
Professor Ryo Kitada notes, "Many individuals are active in many parts of
the society even with the loss of their sight as a child. Developmental
psychology has been advancing its doctrine based on sighted individuals. I wish
this finding will help us grasp how blind individuals understand and learn
about others and be seen as an important step in supporting the development of
social skills for blind individuals."
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