NIH Researchers Identify Brain Circuits Responsible for Visual Acuity
Researchers at the National Institutes of Health (NIH) says they have identified specific brain circuits vital to visual acuity and uncovered how these circuits are disrupted by damage to retinal cells, a discovery that could reshape the future of vision restoration therapies. The research, published in The Journal of Neuroscience, suggests that effective vision repair must go beyond the retina to address the broader neural pathways responsible for processing visual information.
“A huge amount of progress has been made in repairing the eye, however little attention has been paid to the functional consequences beyond the eye,” Farran Briggs, PhD, senior investigator at the NIH’s National Eye Institute (NEI) and lead author of the study, said in an NIH article. “Brain circuits downstream of damaged or dying retinal cells in the eye may also undergo some loss of function following changes to their retinal inputs.”
Visual processing begins with photoreceptor cells in the retina that convert light into electrical signals, which travel through the optic nerve to the brain’s visual centers. Retinal ganglion cells (RGCs) act as intermediaries in this process, relaying visual information to the lateral geniculate nucleus (LGN), a key brain relay center. From there, signals are forwarded to the visual cortex to be interpreted as coherent images.
The NIH research team sought to understand how LGN neurons are impacted when RGCs are damaged. Using a ferret model, they recorded responses in two types of LGN neurons: X-LGN cells, which support visual acuity and fine detail, and Y-LGN cells, which process motion. After inducing RGC injury, the scientists found that X-LGN neurons showed a significant reduction in visual responsiveness, while Y-LGN neurons remained largely unaffected.
“These findings indicate that visual acuity pathways are more sensitive to retinal degeneration than motion pathways,” said Dr. Briggs. “This highlights the need for therapies that go beyond simply repairing or replacing cells in the retina and instead consider the broader visual processing network.”
While current therapies like gene and stem-cell treatments focus on restoring retinal function, this study emphasizes the need to address changes occurring in the brain as well. The researchers propose that future therapies could incorporate vision training techniques—such as video game-based exercises or behavioral interventions—to help retrain and re-engage affected brain circuits.
In addition to vision loss caused by ocular disease or injury, the study's insights may also be relevant to neuropsychiatric disorders like schizophrenia, where abnormal visual perception is common. The team hopes their model can be used in future studies to explore how changes in the retina and brain impact visual processing in these conditions.
The study was supported by the in-house research program at NIH/NEI.
Reference:
Yang, J., et al. (2025). Differential impact of retinal lesions on visual responses of LGN X and Y cells. The Journal of Neuroscience, June 4, 2025. https://www.jneurosci.org/content/45/23/e0436252025