Evidence of ADHD brain disconnect found

DAVIS, Calif., Jan. 14 (UPI) -- Two brain sectors fail to connect when children with attention deficit hyperactivity disorder try a task measuring attention, U.S. researchers say.

Researchers, whose study results were published in Biological Psychiatry, found two brain areas that usually connect when children react to a cue did not do so in children with ADHD.

"This is the first time that we have direct evidence that this connectivity is missing in ADHD," study researcher Ali Mazaheri of the Center for Mind and Brain at the University of California-Davis said in statement. "The brains of the children with ADHD apparently prepare to attend to upcoming stimuli differently than do typically developing children."

Mazaheri and colleagues measured electrical rhythms from the brains of child volunteers with and without ADHD as they performed tests during which they were asked to react to color or sound cues. The researchers especially looked at the alpha rhythm that showed the brain is disengaged from optimally receiving or processing information.

In children without ADHD there was a drop in alpha wave activity when the tests prompted the visual processing area at the back of the head to prepare to pay attention to a color.

However, children with ADHD showed no such drop in alpha activity and a disconnection between the center of the brain that allocates attention and the visual processing regions.