Surprising discovery about the ability of the adult brain to restore sight

The discovery of how some visually impaired adults came to perceive vision provides a new vision of what the brain can do. The discovery that the adult brain may partially recover from hereditary blindness comes from a collaboration between researchers at the University of California, Irvine School of Biological Sciences and School of Medicine.their thesis biology today.¹

According to a news release, the team was investigating a treatment for Leber Congenital Amaurosis, known as LCA. The term refers to a group of hereditary retinal disorders distinguished by severe visual impairment at birth. Due to mutations in any of more than 20 genes, this condition causes degeneration or dysfunction of retinal photoreceptors.

The university said researchers had found that administering chemical compounds that target the retina called synthetic retinoids could significantly restore vision in children with LCA. I wanted to find out if it works for adults with the condition.

“Frankly, I was amazed at how much this therapy saved the brain circuits involved in vision. He is also a member of the Research Center: “Seeing requires more than an intact, functioning retina. It starts with the eye sending signals throughout the brain. Central circuit.”

Scientists have long believed that the brain needs to receive these signals early in life so that the central circuits can wire themselves correctly.

Collaborators who worked with rodent models of LCA were surprised by their findings.

“Central visual pathway signaling, particularly the circuits handling information from both eyes, was significantly restored in adults,” Gandhi said in a news release. “Directly after treatment, signals from the dominant pathway in mice, the contralateral eye, activated twice as many neurons in the brain.”

But even more surprising, Gandhi said in a news release, that signals from the same-side eye pathway activated five times more neurons in the brain after treatment, and this impressive effect lasted for a long time. is.

“The recovery of visual function at the brain level was much greater than expected from the improvements seen at the retinal level,” Gandhi said in a release. The fact that it works so well supports the new concept that there is visual potential waiting to be triggered.”

According to the news release, the discovery broadens the scope of research possibilities.

“Whenever there is a disappointing discovery about the potential of the brain to adapt and rewire, it tells us a broader concept,” said Gandhi. “This new paradigm may aid in the development of retinoid therapies that more fully rescue the central visual pathway in adults with this condition.”

Gandhi and lead author Dr. Carey Huh, who initiated the project, teamed up with Krzysztof Palczewski, a prominent professor of ophthalmology. Palchewski, director of the Center for Translational Vision Research, is best known for his work on retinoids and the visual cycle. Philip Kiser, Associate Professor of Physiology and Biophysics, an expert in visual cycle biochemistry, helped lead the group. A co-appointment in ophthalmology, Kaiser is a member of the Center for Translational Vision Research.

This study was funded by the National Institutes of Health, the Veterans Administration, and the Research Foundation for Blindness Prevention.

reference

Sunil Gandhi; Carrie Huh. Krzysztof Palczewski. Henri Lainonen; Taylor Nakayama, Julia R. Tomasello et al. Retinoid therapy restores eye-specific cortical responses in adult mice with retinal degeneration. current bioroti. Published September 23, 2022. DOIs: https://doi.org/10.1016/j.cub.2022.09.005