The neural mechanisms behind inattention in children with and without ADHD
Department
Psychology
Faculty Advisor
Aaron Mattfeld
Start Date
1-10-2020 9:00 AM
End Date
1-10-2020 10:00 AM
Abstract
Attention-deficit/hyperactivity disorder (ADHD) is the second most common mental condition among U.S. children and affects 6.1 million individuals between the ages of 2-17 years. Defined by two behavioral features - inattention and hyperactivity - identifying and studying ADHD, especially related periods of inattention, a defining characteristic, poses a significant limitation. Recent studies have identified high reaction time variability (RTV) as a reliable feature of ADHD that may be related to periods of inattention. However, the neural mechanisms behind RTV, and thereby inattention, are not well understood. We hypothesized that activation of the default mode network (DMN) during an externally directed task would be an internal distraction leading to increased RTV in ADHD. The DMN is a functional brain system responsible for internally-directed mental processes. During cognitively demanding externally directed tasks, the DMN is deactivated. We used blood-oxygen-level-dependent (BOLD) functional magnetic resonance imaging (fMRI) while participants with and without ADHD performed a standard sustained attention to response (SART) task. We then examined the DMN activation during episodes of increased vs. regular RTV in children with and without ADHD. In contrast to our prediction, we found that DMN activation was reduced during periods of high RTV in children with ADHD. On the other hand, children without ADHD displayed high DMN activation during periods of elevated RTV. We concluded that the neural mechanisms behind inattention might be more complex than previously assumed and potentially involve the interaction between the DMN with the dorsal attention network (DAN).
File Type
Event
The neural mechanisms behind inattention in children with and without ADHD
Attention-deficit/hyperactivity disorder (ADHD) is the second most common mental condition among U.S. children and affects 6.1 million individuals between the ages of 2-17 years. Defined by two behavioral features - inattention and hyperactivity - identifying and studying ADHD, especially related periods of inattention, a defining characteristic, poses a significant limitation. Recent studies have identified high reaction time variability (RTV) as a reliable feature of ADHD that may be related to periods of inattention. However, the neural mechanisms behind RTV, and thereby inattention, are not well understood. We hypothesized that activation of the default mode network (DMN) during an externally directed task would be an internal distraction leading to increased RTV in ADHD. The DMN is a functional brain system responsible for internally-directed mental processes. During cognitively demanding externally directed tasks, the DMN is deactivated. We used blood-oxygen-level-dependent (BOLD) functional magnetic resonance imaging (fMRI) while participants with and without ADHD performed a standard sustained attention to response (SART) task. We then examined the DMN activation during episodes of increased vs. regular RTV in children with and without ADHD. In contrast to our prediction, we found that DMN activation was reduced during periods of high RTV in children with ADHD. On the other hand, children without ADHD displayed high DMN activation during periods of elevated RTV. We concluded that the neural mechanisms behind inattention might be more complex than previously assumed and potentially involve the interaction between the DMN with the dorsal attention network (DAN).