Distractions turn on different part of our brains and do so more quickly than the daily grind of paying attention, neuroscientists have discovered.

Separate regions are responsible for the different ways our brain focuses on the world around us, according to the study by MIT researchers, and our brain waves even pulsate at different frequencies depending on the type of outside stimulus.

"Neural activity goes up and down in a regular periodic way, with everything vibrating together," said study co-leader and neuroscientist Earl K. Miller. "It is faster for automatic stimulus and slower for things we choose to pay attention to."

The findings, detailed in the March 30 issue of the journal Science, could help scientists develop treatments for Attention-Deficit/Hyperactivity Disorder (ADHD). About 4.4 million youth ages 4-17 in the United States have been diagnosed with ADHD, according to the Centers for Disease Control and Prevention.

Top-down approach

Scientists have always recognized two different ways that the brain processes information coming from the outside world. Willful focus (as occurs when you gaze at a piece of art) produces what are called "top-down" signals, while automatic focus (like when a wailing siren snaps you to attention) produces "bottom-up" signals.

What they didn't know was that these signals originate in completely different parts of the brain, said Miller.

Studying monkeys assigned to different tasks, Miller and co-author Timothy J. Buschman found that when a picture or object "popped out" at the creature, the parietal cortex jumped into action. When the monkeys were merely searching for the object, however, it was activity in the prefrontal cortex controlling the brain. This finding is the first to support this difference with concrete evidence.

Top-down and bottom-up brain waves also bounce around our noggins at different frequencies, the researchers found, like the different wavelengths found along points on a radio dial.

And the change in neural activity doesn't have to be due to a stimulus humans perceive as being dangerous, versus something harmless or benign, Miller noted.

"Anything that stands out as different from everything else - like a red apple in the middle of a green field - tends to grab your attention," and kick in the bottom-up or automatic reaction, Miller told LiveScience.

Hope for ADHD

The findings indicate that people suffering from ADHD (sometimes called just ADD) need particular care, depending on their individual symptoms. Some merely have a hard time focusing for long periods of time, while others are constantly distracted and tend to be hyperactive, for example.

Better treatments for the disorder could become available with further research, Miller hoped.

"The problem with neuro-psychotic drugs is that they tend to be very broad, while the goal of psychiatric medicine is to fix what's wrong specifically. Now that we know these are different mechanisms at work, maybe we can target them differently" and balance out or turn down the volume on frequencies that are too dominant, he said.