Eye-opening discovery about the adult brain’s ability to restore sight

A discovery about how some visually impaired adults can begin to see offers new insight into the potential of the brain. The discovery that the adult brain has the ability to partially recover from inherited blindness comes from a collaboration between researchers at the University of California, Irvine School of Biological Sciences, and the School of Medicine. Their paper appears in current biology.

The team was examining a treatment for Leber’s congenital disease, known as LCA. The term refers to a group of inherited retinal diseases characterized by severely impaired vision at birth. The condition, which is caused by mutations in any of more than twenty genes, causes degeneration or impairment of the photoreceptors of the retina.

Administration of chemical compounds that target the retina, called synthetic retinoids, can restore a remarkable amount of vision in children with LCA. The UCI team wanted to see if treatment could make a difference for adults with this condition.

“Honestly, we were astounded by how much the treatment saved the brain circuits associated with vision,” said Sunil Gandhi, professor of neuroscience and behavior and corresponding author. Gandhi is a fellow at the UCI Center for the Neurobiology of Learning and Memory and a member of the Transitional Vision Research Center. “Vision involves more than a healthy, working retina. It begins in the eye, which sends signals throughout the brain. It’s in the brain’s central circuits where visual perception actually originates.” Until now, scientists believed that the brain must receive these signals in childhood in order for the central circuits to properly communicate themselves.

Working with rodent models of LCA, collaborators were surprised by what they found. “Central visual pathway signals are significantly restored in adults, especially the circuits that deal with information from both eyes,” Gandhi said. “Immediately after the treatment, the signals coming from the other side of the eye, which is the dominant pathway in the mouse, activate the neurons in the brain to weaken. Most surprisingly, the signals come from the same – the lateral eye pathway activated five times as many neurons in the brain after the treatment and it was This impressive long-term effect.The restoration of visual function at the level of the brain was much greater than expected from the improvements we saw at the level of the retina.The fact that this treatment works well in the central visual pathway in adulthood supports a new concept, that there is a possibility Latent vision just waiting to be triggered.”

This discovery opens up exciting research possibilities. “When you have a discovery that goes against your expectations about the possibility of the brain being adaptive and rewiring, it teaches you a broader concept,” Gandhi said. “This new model could aid the development of retinoid therapies to fully salvage the central visual pathway in adults with this condition.”

Gandhi and first author Kari Huh, Ph.D., who started the project, teamed up with Krzysztof Balchowski, distinguished professor of ophthalmology. Palczewski, director of the Translational Vision Research Center, is best known for his work on retinoids and the visual cycle. Philip Keser, assistant professor of physiology and biophysics, and expert in visual course biochemistry, helped lead the group. Keser, who holds a joint appointment in ophthalmology, is a member of the Transitional Vision Research Center.

The research was funded by the National Institutes of Health, the Department of Veterans Affairs and the Blindness Prevention Research Foundation.

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