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Separating movement from sight when studying the brain’s visual cortex

November 2, 2023

In primates, activity in the visual cortex—a part of the brain that processes signals from the eyes—is largely unaffected by the body’s own movements, according to a new study from scientists at the National Eye Institute (NEI). The findings allay recent concerns about the validity of prior research studying signals in the visual cortex, which failed to fully account for body movements.

“Our study also shows the importance of comparing research like this across species,” said Hendrikje Nienborg, Ph.D., chief of the NEI Visual Decision Making Section and lead author of a report about the study. 

Kang, Talluri and Nienborg

From left, Incheol Kang, Ph.D.; Bharath Talluri, Ph.D.; and Hendrikje Nienborg, Ph.D.

For decades, researchers have explored how our brains process visual information. During these experiments, the researchers often ignored the animals’ own body movements. However, animals interact with the environment by moving their bodies. In recent studies in rodents, researchers found neural activity from body movements throughout many areas of the brain, including the visual cortex. While it is possible – with modern technology – to account for these movement signals, many earlier studies in primates (including humans) have not directly done so. The findings from the rodent studies put the validity of years of research in doubt.

In a new study, scientists led by Nienborg, have found that, unlike in rodents, movement creates very little neural activity in the primate visual cortex. Further, the small amount of movement-related neural activity the scientists found turned out to be simply due to changes in visual information from the eye moving, not the movement itself.

Incheol Kang, Ph.D., and Bharath Talluri, Ph.D., in Nienborg’s lab, are co-first authors of the study. The research was supported by the NEI, the German Research Foundation, and the National Science Foundation.

Talluri BC*, Incheol K*, Lazere A, Quinn KR, Kaliss N, Yates JL, Butts DA, and Nienborg H. “Activity in primate visual cortex is minimally driven by spontaneous movements.” Nat Neurosci. 2023 Oct 12. doi: 10.1038/s41593-023-01459-5

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Nienborg, Kang and Talluri discuss the study's findings.