A recent study at the UC Davis Center for Mind and Brain shows evidence highlighting the importance of the disconnection between brain regions in attention deficit hyperactivity disorder (ADHD) in children.
The study, conducted by Ali Mazaheri and several colleagues, is the first to directly show that two brain areas fail to connect in children with ADHD as they perform an attention-demanding task.
“The study suggests a functional brain correlated of this attention disorder that will not permit important lines of experimentation to go forward,” said George Mangun, professor of psychology and neurology and researcher at the Center for Mind and Brain, in an e-mail interview.
In the study, researchers placed electrodes that recorded the brain waves in children with ADHD and volunteers without the disorder. The participants were then asked to perform an attention-intensive task.
The task required both groups to watch a computer monitor and press buttons indicating what they saw. After the task, researchers analyzed the data in correlation with the participant’s performance.
“We could then use sophisticated signal analysis techniques on the brains waves as a function of task performance,” Mangun said.
Researchers measured one specific electrical rhythm from the brain, the alpha rhythm. This wave is sent from the frontal cortex to other parts of the brain, especially the visual processing regions, to signal when attention is needed. As this occurs, the alpha rhythm activity should drop.
The study found that children with ADHD do not show this drop in alpha rhythm activity.
“This is one of the first investigations demonstrating evidence of a proposed functional disconnection between brain regions in individuals with ADHD,” said Blythe Corbett, associate clinical professor of psychology and neurology, in an e-mail interview. “These differences were observed between frontal regions, which are involved in higher order cognitive processing skills such as cognitive control, and the occipital cortex, which is especially involved in visual processing.”
By identifying exact differences in the brains of patients versus healthy individuals, diagnoses of the disorder will improve.
“This pattern could be related to one form of the disorder and not another, and that as a result, might improve the diagnosis,” Mangun said.
Importantly, the study makes reference to the fact that ADHD may have mechanisms that could signal a disruption in the brain’s voluntary control over the focus of attention, Mangun said.
Implications of the study focus mainly on discovering precise methods to deal with the disconnection between the brain regions.
“The immediate and long term goal is to pinpoint what may be different in the brain in patients with ADHD, and then go about developing the most effective methods to ameliorate the negative impact of the disorder, and improve the health and welfare of those afflicted,” Mangun said.
SADAF MOGHIMI can be reached at firstname.lastname@example.org.