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.