Juvenile plasticity returned to adult mice brains

By enabling the rigid brains of adult mice to return to the high levels of plasticity found in juvenile brains, scientists are opening new pathways to the treatment of brain injuries such as stroke. Back in 2013, researchers from YaleUniversity reported the discovery of a molecular switch that achieved this result, and now scientists at the University of California, Irvine, have managed to make an old brain young again using a different approach.

The UC Irvine technique involvedtransplanting a type of embryonic neuron into the brains of adult mice. Aftertransplantation, these neurons expressed GABA (gamma-Aminobutyricacid), a chief inhibitory neurotransmitter in the mammalian central nervoussystem that aids in motor control, vision and numerous other corticalfunctions.

This resulted in areturn to youthful plasticity in the mouse's adult brain that allowed rapid and robustchanges in neural pathways and synapses in response to learning and experience.

Like the Yaleteam, the UC Irvine researchers say their technique could be used toaccelerate rehabilitation following brain injuries, but addedthe research could lead to new treatments for developmental brain disorders,such as autism and schizophrenia, as well as therapies for currently incurablebrain disorders.

Demonstrating thepotential for future clinical applications for GABA neuron transplantation, theresearchers also used it to restore normal sight to adult mice with amblyopia,or lazy eye. Amblyopia is a long-lasting visual deficit that results when visualstimulation is transmitted through the optic nerve to the brain poorly, or notat all, for an unbroken period of time. In an attempt to correct the problem,UC Irvine neurobiologist Sunil Gandhi and his colleagues transplanted theGABA-expressing neurons into the visual cortex of adult mice with the condition.

"Several weeks after transplantation, when the donoranimal’s visual system would be going through its critical period, theamblyopic mice started to see with normal visual acuity," said MelissaDavis, a postdoctoral fellow and lead author of the study.

The team alsobelieves that such research could help shed light on the basic mechanismsresponsible for "critical periods" of brain development.

Their research appears in the journal Neuron.

Source: UC Irvine