Brain Plasticity Boosts Sense of Sight in Deaf

Dr. Stephen G. Lomber of the Centre for Brain and Mind at the University of Ontario in Canada lead a team of researchers that found that the brain reorganizes parts of itself normally used for hearing in order to boost sight in deaf people. The research was published online in the journal Nature Neuroscience.

The specific study involved studying the brains of cats that were born deaf. It has been known that deaf and blind people often report an enhanced ability in other senses but it was not known how this process came about neurologically. The research team found that the brain has a certain “plasticity” to reassign areas normally dedicated to one sense in order to boost the performance of a remaining sense. More specifically, the team found that the brains of the deaf utilize the redundant auditory brain areas to improve visual performance in two ways: enhancing peripheral vision and detecting how fast things around them are moving. Lomber said, “The brain is very efficient, and doesn’t let unused space go to waste,” further hypothesizing that, “cross-modal reorganization of deaf auditory cortex may provide the neural substrate mediating compensatory visual function.” After putting congenitally deaf cats and hearing cats through a series of tests, it was found that the deaf cats had superior localization in the peripheral field and lower visual movement detection thresholds. When the posterior auditory complex (part of the brain that detects peripheral sound) was deactivated through surgery, it was found that the cats lost their enhanced peripheral visualizing skills. This lead the team to suggest that the function of the brain area to detect peripheral signals stayed the same but it switched from auditory to visual in nature. Lomber concluded that, “Our results indicate that enhanced visual performance in the deaf is caused by cross-modal reorganization of deaf auditory cortex and it is possible to localize individual visual functions in discrete portions of reorganizaed auditory cortex.”

I found this article to be interesting because of the analysis of the brain’s characteristic quality of “plasticity” that allows it to modify itself to suite new situations. This quality of the brain encompasses much of the focus of our course on human physiology which is the body’s response to different stimulate in an attempt to maintain a homeostasis. In this example, the body has lost one of its senses and therefore the information from the physical world associated with that sense. In response, the body boosts another intact sense to allow another avenue for more information to be processed. This fascinating plasticity of the brain was also explored in one of our SNBAL assignments. Brain plasticity has a promising future for teaching us more about the brain and its manipulation in order to prevent and treat different diseases that affect the brain.

Article Source: http://www.medicalnewstoday.com/articles/204333.php
Alexander J. Quante '13 -- VTPP 434