August 12, 2015

Brain plasticity after vision loss has an ‘on-off switch’

A molecular on-off switch in the brain controls which senses
compensate for vision loss in one eye © Shutterstock

(August 12, 2015)  KU Leuven biologists have discovered a molecular on-off switch that controls how a mouse brain responds to vision loss. When the switch is on, the loss of sight in one eye will be compensated by the other eye, but also by tactile input from the whiskers. When the switch is off, only the other eye will take over. These findings may help improve patient susceptibility to sensory prosthetics such as cochlear implants or bionic eyes. 

Our brain adjusts to changes of all kind. This brain plasticity is useful for neural development and learning, but also comes into play when the nervous system is damaged. For instance, when we lose sight in one eye, our brain no longer receives sensory input from that eye, but it will compensate for that loss.

Research in adult mice has revealed two types of neuroplasticity in response to vision loss. “When a mouse loses sight in one eye, the remaining eye starts sending additional signals to the area in the brain that used to be served by the lost eye,” biochemist Julie Nys from the KU Leuven Laboratory for Neuroplasticity and Neuroproteomics explains. “After a while, the whiskers of the mouse – its sense of touch – step in as well. After a couple of weeks, the ‘lost’ area in the brain is entirely reclaimed and its brain activity is almost as high as it was before.” This phenomenon, whereby the brain responds to sensory loss by combining input from several sensory systems, is known as cross-modal neuroplasticity.

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