Scientists unravel how brain always gets it right

December 19th, 2008 - 5:54 pm ICT by IANS  

Sydney, Dec 19 (IANS) What does your brain do as soon as you notice a door handle? It is already hard at work, noticing more and more details. A simple door handle turns into a silver-plated antique-style-door-handle facing-right. Information about the handle also reaches the part of your brain responsible for planning movements, allowing you to turn the handle with your right hand and open the door.

However, this is not necessarily a simple process for the brain. For instance, how do we end up turning the door handle with our right hand, instead of with the other?

During this analysis, the brain is bombarded with a lot of irrelevant information, so it relies on a control system to filter out unnecessary information.

In the visual system, this control mechanism is known as centre surround inhibition (CSI) and it works by activating only the neurons that are required for further action.

In other words, if any extra neurons are turned on, this CSI will shut them off, so that the brain can focus on the relevant information.

Although the CSI system has been well documented it was not known if this type of control mechanism exists in the motor regions of the brain.

Daniel Loach, psychologist from Macquarie University, Sydney and his colleagues conducted a set of experiments to explore inhibitory mechanism in the areas of the brain involved in planning movements.

A group of participants were successively shown two door handles and had to press a left or right button which corresponded to the texture (either wood or metal) of the second handle.

Some of the pairs had both of the handles in the same orientation, in other pairs the two handles would be rotated at varying angles, said a university release.

In addition, the researchers noted which hand was used to make the response - if it was compatible or incompatible with the direction the handle was facing (for example, the right hand was compatible for handles that were facing right).

These results indicate that there is a common mechanism which acts in both perception and movement. These findings also tell us how information travels throughout the brain and how the motor system and visual system interact.

The results were published in the December issue of Psychological Science, a journal of the Association for Psychological Science.

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