June 8, 2009

The brain blocks information from us

U.S. scientists have found a widely held theory concerning the brain and perception is incorrect and that the brain blocks some information from awareness.

Rutgers University researchers have discovered visual input obtained during eye movements is processed by the brain, but blocked from our awareness.

The process of seeing requires the eyes to move so light can hit the photoreceptors at the center of each retina, which then pass that information to the brain, the scientists said. "If we were cognizant of the stimulus that passes before the eyes during the two to three times they move every second, however, vision would consist of a series of sensations of rapid motion rather than a stable perception of the world.

To achieve perceptual stability, current theory has held that visual information gained during an eye movement is eliminated, as if cut off by a camera's shutter, and removed from processing, they said.

But the new study led by Assistant Professor Bart Krekelberg and researcher Tamara Watson shows that theory is incorrect and what the brain is actually doing is processing information gained during eye movement, but blocking it from being reported.

The findings, among other things, show a new approach is needed to gain additional understanding into cognitive and neural functions involved in visual processing and perceptual stability, the researchers said.

The study appears in the journal Current Biology.