Brain Region that Recognizes Human Hand Gestures Develops Even in the Blind

It turns out that the region of the brain that recognizes human hand gestures is the same for both blind and sighted individuals. The findings reveal that the neural network responsible for this recognition forms the same way, even without visual information.

Our brains perceive human gestures and then interpret them. A part of our brains, called the visual cortex, processes the gestures that we see and actually supports this mechanism. That's why scientists wanted to see whether the same pathways were activated when it came to blind individuals.

In this latest study, scientists tested both blind and sighted volunteers. Individuals were instructed to touch plastic casts of hands, teapots and toy cars and identify the shape with their eyes closed. In the end, both sighted and blind individuals could make identification with the same accuracy.

Then, the researchers used functional magnetic resonance imaging (fMRI) to measure the activated brain region. Scientists actually pinpointed a common activated brain region for both sighted and blind individuals when it came to the plastic casts of hands. In addition, the researchers found that there was a region that showed signs of activity dependent on the duration of the visual experience; this region functioned as a supplement when recognizing hand gestures.

"Many individuals are active in many parts of the society even with the loss of their sight as a child," said Ryo Kitada, one of the researchers, in a news release. "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."

The findings are published in The Journal of Neuroscience.