Why do distracted rats and humans act similarly?

Distracted rats and humans tend to act similarly when they have to choose an object from a specific lot.

The process known as 'feature binding' enables the brain to choose only the required object rather than any other object.

For example, when offered a basket full of fruits, the brain immediately gets to work, connecting (binding) information about each item's shape to its colour to ensure that we select the green apple we are craving instead of a green pear.

But when any kind of distraction impairs feature binding, we end up by sinking out teeth into the green pear instead.

It was well known which areas of the brain are involved in feature binding, but it was unclear which neurotransmitters (brain chemicals) were active in the process.

Psychologists Leigh C.P. Botly and Eve de Rosa of the University of Toronto wanted to investigate if acetylcholine is involved in feature binding.

Acetylcholine is a neurotransmitter that is important for attention and seemed like a good candidate for playing a role in feature binding as well.

A group of volunteers participated in a feature binding task (choosing among various shapes and colours), with some of them being distracted throughout the duration of the task.

The psychologists also developed a feature binding task for rats (having them choose among variously scented food bowls) and treated some of the animals with the drug scopolamine, which temporarily blocks the effects of acetylcholine.

The results, showed that patterns of behaviour were very similar in distracted humans and rats on scopolamine, said a release of the Association for Psychological Science.

Both the drug treated rats and distracted humans had a decreased ability to complete the feature binding task, although their ability to process just single features of an object (specific colour or odour) was not affected.

The authors note that "acetylcholine may provide the attentional 'glue' for feature binding".

Their findings could open the way to improved therapies for disorders like Alzheimer's.

The study was reported in the November issue of Psychological Science.

Last updated on Nov 19^th, 2008 at 10:32 am IST--IANS