Brain Process Underlying Recognition of Hand Gestures Found to Develop Even When Blind

Researchers have discovered by using neuroimaging that activated brain regions of congenitally blind individuals and activated brain regions of sighted individuals use common brain 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 investigators set out to find out if a distinctive mechanism occurs in the brain of congenitally blind individuals when understanding and learning others’ gestures and whether it is the same process that occurs in sighted individuals. 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 were published July 23, 2014, in the Journal of Neuroscience. Brain processes perceive human bodies from inanimate objects and shows a particular response. A part of a region of the visual cortex region of the brain that processes visual information supports this mechanism. Because visual data are mostly used in perception, this is understandable, however, for perception using haptic information and also for the recognition of one’s own gestures, it has been recently determined that the same brain region is triggered. The investigators believe 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 Assist. Prof. Ryo Kitada of the National Institute for Physiological Sciences, National Institutes of Natural Sciences (Okazaki, Aichi, Japan). With their eyes closed, they were told to touch toy cars, plastic casts of hands, and teapots, and identify the shape. Sighted individuals and blind individuals were found to both make an identification with the same accuracy.

By measuring the activated brain region using functional magnetic resonance imaging (fMRI) scanning, for plastic casts of hands and not for teapots or toy cars, the researchers were able to locate a common activated brain region, irrespective of visual experience. However, it also revealed a region showing signs of activity that is dependent on the duration of the visual experience, and that this region acts as a supplement when recognizing hand gestures.

As Assist. Prof. Ryo Kitada noted, “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.”

Related Links:
Japanese National Institute for Physiological Sciences