Scientific studies – but especially anecdotal evidence – would suggest that people who lose their sight develop a better sense of hearing. But what really happens in the brain? Researchers have answered this question.
According to the World Health Organization (WHO), approximately 1.3 billion people worldwide suffer from some form of visual impairment (from mild vision problems to blindness), and this number is only expected to increase. . We have all heard the stories of people who have developed better hearing after losing their sight, some even a better sense of touch. The brain would adapt to allow visually impaired people to move around using their other senses. Researchers wanted to verify this theory scientifically.
What’s really going on in the auditory cortex of a blind person? This new study, published in the Journal of Neuroscience sought to identify the real changes that occur in the brains of people who lose their sight at a young age.
A more efficient auditory cortex in the visually impaired
Previous studies have shown that when people have early visual impairment, the occipital cortex – usually responsible for “deciphering” visual information from the eyes – adapts to processing information from other parts of the body. But this new study shows that another part of the brain, the auditory cortexalso adapts to process sound differently and “compensate” for loss of sight.
To reach this conclusion, the study’s lead author, Kelly Chang, and her team studied these changes in people with early onset blindness, especially anophthalmia (a rare disease in which children are born without an eye or with only one eye). They compared them to a control group of sighted individuals. The researchers studied the MRI activities of the participants’ brains when they heard sounds – sounds that sounded the same at different frequencies – and analyzed what was happening in their auditory cortex. These analyzes revealed that although blind and visually impaired participants had a similar sized auditory cortex, this region captured frequencies better in visually impaired people.
To better understand the mysteries of our brain and its ability to adapt, the team of researchers now wants to study what happens in the brains of people who have lost their sight later in life, but also in those of people who were able to regain their sight.
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