Youngsters with attention disorders may struggle to concentrate on boring tasks because part of their brain does not switch off in the same way as those without the condition, researchers say.
Brain scans studied by researchers at the University of Nottingham found that when incentives were low, children with attention deficit hyperactivity disorder did not “switch off” brain regions involved in mind-wandering.
When the incentives were high, or when the youngsters took their medication, their brain activity was the same as a child without the condition.
Professor Chris Hollis, of the School of Community Health Sciences, said: “For the first time we are beginning to understand how in children with ADHD incentives and stimulant medication work in a similar way to alter patterns of brain activity and enable them to concentrate and focus better,” he said.
“It also explains why in children with ADHD their performance is often so variable and inconsistent, depending as it does on their interest in a particular task.”
Researchers from the Motivation, Inhibition and Development in ADHD Study (MIDAS) group used a “Whac-a-Mole” style game to assess 18 youngsters aged between nine and 15 years old, against scans of a similar group of children without the condition.
The children with ADHD were tested when they were taking their methylphenidate and when they were off their medication. All participants were given extra points incentives at certain points in the game.
By studying the brain scans, the researchers found that typically developing children switched off their default mode (DMN) network whenever they saw an item requiring their attention.
However, children with ADHD did not switch off their DMN unless the incentive was high, or they had taken their medication. Incentives made no difference to children without ADHD; activity in their DMN was switched off by items requiring their attention regardless of the incentive on offer.
Dr Martin Batty, of the MIDAS group, said: “Most people are able to control their ‘daydreaming’ state and focus on the task at hand. This is not the case with children with ADHD.
“If a task is not sufficiently interesting, they cannot switch off their background brain activity and they are easily distracted. Making a task more interesting — or providing methylphenidate — turns down the volume and allows them to concentrate.”
Task-related Default Mode Network modulation and inhibitory control in ADHD: effects of motivation and methylphenidate. Journal of Child Psychology and Psychiatry
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