It's a no-brainer - we are all multi-nationals

(Agencies)
Updated: 2009-03-04 09:53

The brain behaves like an international corporation to perform even the simplest of tasks, says a new study.

Sending an e-mail or eating a sandwich provoke a complex decision-making process in a key region of the brain called the pre-frontal cortex, located just behind the forehead.

"It is among the strongest evidence to date for a systemic organization of the frontal cortex," says lead author David Badre of Brown University in Providence, Rhode Island.

The entire path requires the brain to make out both abstract and concrete decisions but when any of the tissues is damaged, only the abstract decisions - choosing the sandwich, for example - are impaired, leaving the more mechanical task of actually bringing the food to one's mouth is unaffected.

Earlier research had shown that the pre-frontal cortex handles so-called "executive functions", for instance resolving conflicting thoughts, achieving goals and exercising social control over sexual and emotional urges.

Neuroscientists have been widely agreed that its role also requires it controls the capacity to plan, reason, conduct higher-level thinking and connect what we know about the world to how we behave.

Quite how the information pouring in from all the senses is organized, however, has been hotly debated.

The new study adds weight to theories pointing to a flow of decision-making within the pre-frontal cortex in which abstract trumps concrete.

"It is like a hierarchy in a company. The CEO (chief executive officer) can direct the people directly below him, or all the way down to the lowest levels," says Badre. "But the person in the mail room can't direct the CEO, so there is an asymmetry of influence."

Badre's team arrived at these conclusions by studying 11 stroke victims who had suffered damage to different parts of the frontal lobe.

The patients were given a series of four tests that required progressively greater degrees of complexity and abstract thinking. The location of their lesions along the abstract-to-concrete axis in the frontal lobe corresponded to how well they performed.

"If you take out the middle manager" - the equivalent of damaged brain tissue - "the people in the mailroom can still operate," Badre says, extending the metaphor. "But they can no longer be directed, even if they need to be."

The findings, published in the journal Nature Neuroscience, fill in an important piece of the puzzle of how this part of the brain affects human behavior and, says Badre, could also lead to new treatments for stroke victims.