Brain activity is structured into brain rhythms that differ in frequency, with different frequencies reflecting different mental states. But these brain waves, especially the alpha waves at 10Hz, also have functional roles that still need to be clarified.

By recording brain activity on the surface of the scalp and using electroencephalographic and mathematical techniques of inverse correlation, Rufin VanRullen and Diego Lozano-Soldevilla showed that alpha waves were true “perceptual echoes” propagating over several cycles and in a very precise organization. This organization makes it possible to postulate that perceptual echoes behave like “radar screens” that would scan the visual field rhythmically every 100ms, thus making it possible to locate an object in space and time; each position in the surrounding space is scanned at different times and in a well-defined order. These results published in Cell Reports make it possible to propose for the first time a functional role for these brain waves at 10 Hz, which would be a direct reflection of the cortical processing of sensory information. Link for article