A study led by neuroscientists at Georgetown University in the US has revealed that the part of the brain that receives and processes visual information in sighted people develops a unique connectivity pattern in people who are born blind or visually impaired. The scientists say this pattern in the primary visual cortex is unique to each person, like a fingerprint.
The findings, published July 30, 2024, in the journal PNAS, suggest that the discovery has profound implications for understanding brain development and could help inform personalized rehabilitation and vision restoration strategies.
What we know and what we don’t know
Scientists have known that the visual cortex of people born blind responds to a variety of stimuli, including touch, smell, sound localization, memory recall, and language. But the lack of a common thread linking the tasks that activate primary areas of the visual cortex has puzzled researchers. The new study, led by postdoctoral researcher Lina Amaral and Ella Stremm-Amit, an assistant professor of neuroscience at Georgetown University School of Medicine, offers a compelling explanation: differences in how each individual’s brain is organized.
“We don’t see this level of variability in visual cortex connectivity across sighted individuals,” said Stremm-Amit, who leads the Sensory and Motor Plasticity Lab at Georgetown University, according to EurekAlert. “Visual cortex connectivity is usually very consistent. The connectivity pattern in people born blind is much more variable across people, like an individual’s fingerprint, and is consistent over time, to the point that an individual person can be identified by their connectivity pattern.”
the study
The study involved a small sample of people who were born blind and underwent functional magnetic resonance imaging (fMRI) scans over a two-year period. The researchers used a neuroimaging technique to analyze neural connections across the brain.
“The visual cortex of people born blind showed remarkable stability in its connectivity patterns over time,” explains researcher Amaral. “Our study found that these patterns did not change significantly based on the task at hand, whether participants were identifying sounds, identifying shapes, or simply resting. Instead, the connectivity patterns were unique to each individual and remained stable over the two-year study period.”
brain plasticity
“These findings tell us how the brain grows,” said researcher Streim-Amit. “Our findings suggest that experiences after birth shape the diverse ways in which our brains can grow, especially if we grow up blind. Brain plasticity in these cases allows the brain to grow, and perhaps even to use the visual cortex differently among different people who are born blind.”
Researchers hypothesize that understanding each person’s individual brain connectivity may be important for improving rehabilitation and vision restoration solutions for individuals with blindness, based on their unique neural connectivity pattern.