Washington ? Spot a bear in the woods, and a different part of your brain will yell “pay attention” than if you were studying bears at the zoo.

New research shows it takes one part of the brain to start concentrating and another to be distracted. This discovery could help scientists develop better treatments for attention deficit disorder.

“This ability to willfully focus your attention is physically separate in the brain from distracting things grabbing your attention,” said Earl Miller, a neuroscientist at the Massachusetts Institute of Technology. He led the study, published in today’s edition of the journal Science.

There are two main ways the brain pays attention: “top down” or willful, goal-oriented attention, such as when you focus to read, and “bottom-up” or reflexive attention to sensory information – loud noises, bright colors or threatening animals.

Likewise, there are different degrees of attention disorders. Some people have a harder time focusing, while others have a harder time filtering out distractions.

Scientists knew that paying attention involved multiple brain regions but they did not know how, because studies have examined one region at a time.

Miller hooked painless electrodes onto monkeys to track how two key areas react together when the brain jumps to attention.

The monkeys were trained to take attention tests on a video screen in return for a treat of apple juice. Sometimes they had to concentrate, picking out, say, only the left-leaning red rectangle from a field of red rectangles. Other times bright rectangles – the attention-grabbers – flashed off the screen at the monkeys.

When the monkeys voluntarily concentrated, the so-called executive center in the front of the brain – the prefrontal cortex – was in charge. But when something distracting grabbed the monkeys’ attention, that signal originated in the parietal cortex, toward the back of the brain.

The electrical activity in these two areas began vibrating in synchrony as they signaled each other. But it was at different frequencies.

Sustaining concentration involved lower-frequency neuron activity. Distraction occurred at higher frequencies. So, Miller concluded, scientists one day might find a treatment that essentially turns up or down the volume to boost attention.

The study provides the first good look at how these physically distinct brain regions interact to govern at least part of attention, said Dr. Debra Babcock, a neurologist at the National Institutes of Health.

“Once we understand how attention works, we’ll understand how better to treat disorders of attention, and lord knows there are plenty of those,” Babcock said. “This could, in the long term, help us devise therapies.”