Discoveries Shed New Light on What the Eyes See
Brain Blocks Information from Awareness to Provide a Balanced View of the World
In life, it’s not always what we perceive, but also what we ignore that allows us to function with ease. Research by Bart Krekelberg and his lab at Rutgers University in Newark reveals that in the process of seeing our brain makes a very selective choice about the information it reports back to awareness.
As reported in the June 23, 2009 issue of Current Biology, Krekelberg and his former post-doctoral researcher Tamara Watson disproved the popularly held theory that holds that information obtained during eye movement is blocked as if by a camera shutter. Rather than being blocked, their research shows that information obtained during eye movements is processed by the brain, but the brain opts not to report that back to awareness. If that information were not blocked or reported back to awareness then vision would be like seeing the world through a jerky hand-held camera.
“What our research shows is that perceptual stability is not accomplished by suppressing stimuli encountered during eye movement, or removing them from processing, but rather that those signals are prevented from reaching awareness at a later stage of processing,” says Krekelberg.
The findings are an important step forward in providing a map of the neural activity involved in visual processing and could open the way for better treatment of visual dysfunctions involved in dyslexia and other disorders.
One reason why the brain does not function like a camera shutter, cutting information off from processing, may be that the visual input obtained during eye movement actually is needed to convey a stable image of the world.
“The visual signals generated by eye movements may be important for determining how much and how fast the eye moved so the brain can maintain perceptual stability,” says Watson. “It may be that these signals are useful for improving perceptual stability as long as they do not enter into awareness.”
The findings also show that a new approach is needed to gain a deeper understanding into the cognitive and neural functions involved in visual processing and perceptual stability. Until now, research largely has focused on pinpointing those areas of the brain that show lower activity during eye movement.
“What we are seeing now is that things are much more complex than we suspected,” says Krekelberg. “We shouldn’t just be looking at areas of reduced activity in the brain during eye movements, but for areas that may change their processing to make use of the input that arises during eye movements.”
Working under grants from the National Institute of Health, the Pew Charitable Trusts,and the Charles and Johanna Busch Foundation, Krekelberg hopes to pinpoint how those areas of the brain involved in visual perception and eye movements work together to provide us with a steady image of the world.
Born in the Netherlands, Bart Krekelberg earned his Ph.D. in mathematics from the University of London (King’s College) in 1997. He holds master’s degrees in theoretical astrophysics and cognitive artificial intelligence from Utrecht University. Prior to joining the Rutgers University faculty, he worked as a post-doctoral fellow at Ruhr University, in Bochum, Germany, and as a research associate at the Salk Institute in La Jolla, California. He joined Rutgers University in Newark in 2006 to establish the Krekelberg Neuroscience Lab at the Center for Molecular and Behavioral Neuroscience. In 2007, he was named one of 20 U.S. Pew Scholars in recognition of the importance of his work in vision and eye movement.
- Neural Dynamics of Saccadic Suppression, Journal of Neuroscience, October 7, 2009
- Recent History of Stimulus Speeds Affects the Speed Tuning of Neurons in Area MT, Journal of Neuroscience, October 10, 2007
- Interactions between Speed and Contrast Tuning in the Middle Temporal Area: Implications for the Neural Code for Speed, Journal of Neuroscience, August 30, 2006
- Neural Correlates of Implied Motion, Nature, August 1, 2003
- The Position of Moving Objects, Science, July 1, 2000
- Postsaccadic Visual References Generate Presaccadic Compression of Space, Nature, February 24, 2000
- Bart Krekelberg is named one of 20 U.S. Pew Scholars for 2007, EurekAlert, Aug. 7, 2007
- The brain blocks information from us, United Press International, June 8, 2009
- Discoveries shed new light on how the brain processes what the eye sees, Rutgers News Release, June 2, 2009
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