Iranian Researchers Discover How Brain Rhythms Organize Visual Perception

Sunday, October 6, 2019 - 10:56

Researchers from Iran University of Science and Technology, German Primate Center -- Leibniz Institute of Primate Research in Göttingen, Germany, and the Institute for Research in Fundamental Sciences in Tehran, Iran discovered the brain's specialized color and motion circuits use different frequencies to broadcast their output to brain areas that combine the various visual feature components into a unified percept.

According to the Science Daily report, neuroscientists measured the activity of individual nerve cells in the brain of rhesus monkeys, while the animals performed a visual perception task. The monkeys were trained to report changes in moving patterns on a computer screen. Using hair-thin microelectrodes, which are painless for the animals, the researchers measured the electrical activity of groups of nerve cells. These signals continuously oscillate over a broad frequency spectrum.

"We observed that faster responses of the animals occurred whenever the nerve cells showed a stronger oscillatory activity at high frequencies, suggesting that these oscillations influence perception and action," explains Stefan Treue, head of the Cognitive Neuroscience Laboratory at the German Primate Center and one of the senior authors of the study.

"Our computational analysis shows that high level regions could use these different frequencies to distinguish the source of neural activity representing the different features," explains Mohammad Bagher Khamechian, scientist at the Iran University of Science and Technology in Tehran and first author of the study.

The detailed knowledge of how the brain of rhesus monkeys enables perception as well as other complex cognitive functions provides insights about the same processes in the human brain. "The oscillatory activity of neurons plays a critical role for visual perception in humans and other primates," summarizes Stefan Treue.

"Understanding how exactly these activity patterns are controlled and combined, not only helps us to better understand the underlying neural correlates of conscious perception, but also may enable us to gain a better understanding of physiological deficits underlying disorders that involve perceptual errors, such as in schizophrenia and other neurological and neuropsychiatric diseases."

The research has been carried out by Mohammad Bagher Khamechian, Vladislav Kozyrev, Stefan Treue, Moein Esghaei, Mohammad Reza Daliri. Routing information flow by separate neural synchrony frequencies allows for “functionally labeled lines” in higher primate cortex.

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