Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Attention acts as visual glue

02.08.2002


When you gaze at a bowl of fruit, why don’t some of the bananas look red, some of the apples look purple and some of the grapes look yellow?

This question isn’t as nonsensical as it may sound. When your brain processes the information coming from your eyes, it stores the information about an object’s shape in one place and information about its color in another. So it’s something of a miracle that the shapes and colors of each fruit are combined seamlessly into distinct objects when you look at them.

Exactly how the brain recombines these different types of visual information after it has broken them apart is called the "binding problem" and is currently the subject of considerable controversy in the neuroscience community. But the results of a brain mapping experiment, published online by the Proceedings of the National Academy of Sciences on July 29, provide significant new support for the theory that attention is the glue that cements visual information together as people scan complex visual scenes.



The study was a collaboration among René Marois, assistant professor of psychology at Vanderbilt; John C. Gore, who recently moved from Yale to become a Chancellor’s University Professor at Vanderbilt; and Yale graduate student Keith M. Shafritz.

"There are more than a dozen places in the brain involved with processing visual information, each specializing in information with slightly different attributes," says Marois. "Some specialize in processing color, some specialize in processing shape, while others specialize in movement. These areas are not clustered together, but distributed widely around the back of the brain."

There are two leading theories about how the brain reintegrates this information.

One view proposes that the neurons in the scattered areas are bound together in a way that allows them to act simultaneously. When you look at a banana, the neurons that store information about the banana’s shape fire simultaneously with the neurons in a different region of the brain that store information about the banana’s color. It is the direct functional interaction between neurons located in different visual areas that binds together an object’s numerous visual properties.

In the 1980’s, Anne M. Triesman at Princeton and her colleagues advanced an alternative mechanism. She proposed that visual binding is mediated by the parietal cortex, an area of the brain known to be involved in spatial attention. She suggested that the act of focusing one’s attention on an object’s spatial location provides the key that binds the different types of visual information together. If an apple is sitting on the table in front of a woman, then her brain, specifically the parietal cortex, associates the information about its color and shape with its location and uses the spatial information to bind together the visual information whenever she focuses her attention on the apple.

The description of a patient who, following a brain injury in the parietal lobe, had difficulty associating colors with more than one object at a time gave Marois the idea for the basic experiment. When the person was presented with objects one at a time, he had no problem properly pairing their shapes and colors. When presented with two or more objects at the same time, however, he often mismatched the color of one object with the shape of another.

So Marois designed a series of trials that asked subjects to concentrate on the shape only, the color only or both shape and color of pairs of objects displayed on a computer screen while their brain activity was monitored using the technique called functional MRI. The researchers presented these pairs to the individuals either sequentially in the same location or simultaneously at different locations and recorded the areas in the brain that were most active.

"The purpose of our study was really to test the attention theory as strongly as we could," says Marois. "I was actually surprised that it worked because we had to adopt such stringent testing conditions."

Despite their stringency, the tests showed that activity in the parietal region increased significantly whenever the individuals were presented with more than one object at the same time.

"This provides strong evidence in favor of the theory that spatial attention is the binding glue that the brain uses to integrate visual objects whenever it is presented with more than one object at the same time, which is most of the time," says Marois.

While the study results support the attention theory, they do not rule out other mechanisms. "In fact," he adds, "it is practically certain that the brain uses several mechanisms to solve this fascinating problem."


The project was funded by a grant from the National Institute of Neurological Disorders and Stroke.

For more news about research at Vanderbilt, visit Exploration, Vanderbilt’s online research magazine at http://exploration.vanderbilt.edu.


David F. Salisbury | EurekAlert!
Further information:
http://exploration.vanderbilt.edu
http://www.vanderbilt.edu/

More articles from Life Sciences:

nachricht Colorectal cancer risk factors decrypted
13.07.2018 | Max-Planck-Institut für Stoffwechselforschung

nachricht Algae Have Land Genes
13.07.2018 | Julius-Maximilians-Universität Würzburg

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: First evidence on the source of extragalactic particles

For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.

To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...

Im Focus: Magnetic vortices: Two independent magnetic skyrmion phases discovered in a single material

For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.

Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...

Im Focus: Breaking the bond: To take part or not?

Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.

A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...

Im Focus: New 2D Spectroscopy Methods

Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.

"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....

Im Focus: Chemical reactions in the light of ultrashort X-ray pulses from free-electron lasers

Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.

Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Leading experts in Diabetes, Metabolism and Biomedical Engineering discuss Precision Medicine

13.07.2018 | Event News

Conference on Laser Polishing – LaP: Fine Tuning for Surfaces

12.07.2018 | Event News

11th European Wood-based Panel Symposium 2018: Meeting point for the wood-based materials industry

03.07.2018 | Event News

 
Latest News

Leading experts in Diabetes, Metabolism and Biomedical Engineering discuss Precision Medicine

13.07.2018 | Event News

Research finds new molecular structures in boron-based nanoclusters

13.07.2018 | Materials Sciences

Algae Have Land Genes

13.07.2018 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>