When you look at a picture, your brain has to put together lines, patterns and shapes to make a meaningful scene. New research by neuroscientists at the University of California, Davis and the University of Minnesota shows that higher regions of the brain can quickly recognize patterns and shapes and tell lower areas of the brain to stop processing the information. The finding confirms predictions from computer models and helps explain how the human brain makes sense of what the eyes see.

Scott Murray, Bruno Olshausen and David Woods from UC Davis and the VA Medical Center in Martinez, with Daniel Kersten and Paul Schrater from the University of Minnesota, Twin Cities, used functional magnetic resonance imaging (fMRI) to see which parts of the brain were active as subjects looked at different patterns and shapes.

Current theories hold that a lower area of the brain called the primary visual cortex responds to simple features such as edges and lines and passes this information on to higher, pattern-recognizing parts of the brain.

When the researchers showed subjects random patterns of lines, the primary visual cortex lit up on the fMRI scan. When the same lines were organized into a shape, a higher part of the brain called the lateral occipital complex (LOC) was activated, but the primary visual cortex was less active. That shows that when the LOC recognizes a pattern in the information it gets from the primary visual cortex, it can send a message back down the pathway to tell the lower area of the brain to stop responding.

"Things in the environment are not random. The higher areas of the brain expect order and pick it out," Murray said. The brain should be better able to detect new or different items if it can pick out common patterns first, he said.

The research is published in the October 28 issue of Proceedings of the National Academy of Sciences of the USA.