The study analyzed differences in brain activity between children with Attention Deficit Hyperactivity Disorder (ADHD) and those without the disorder. The researchers observed a significant reduction in so-called “neural flexibility” in children with ADHD. This term refers to the brain’s ability to rapidly adjust communication between different neural networks according to the demands of a task, a process fundamental to cognitive flexibility.
Attention Deficit Hyperactivity Disorder (ADHD) is one of the most common neurodevelopmental disorders in children, affecting 3% to 5% of children globally.
This disorder is characterized by inattention, impulsivity, and hyperactivity symptoms, which are often developmentally inappropriate and interfere with the child’s ability to learn and interact socially. In many cases, these symptoms persist into adulthood, which increases the importance of early diagnosis and intervention.
The diagnosis of ADHD currently relies primarily on behavioral assessments performed after symptoms have manifested. However, the subjectivity involved in these assessments can compromise diagnostic accuracy, so there is great interest in more objective and standardized diagnostic methods.
With the advancement of machine learning (artificial intelligence, AI) and neuroimaging techniques, new possibilities for identifying ADHD and more accurately predicting clinical outcomes using specific brain data have emerged.
A recent focus is on “neural flexibility,” which refers to the ability of brain areas to change their communication between different networks, which is essential for cognitive flexibility, the ability to switch between tasks or adapt thinking to new contexts.
In children with ADHD, neuroimaging studies show reduced neural flexibility, indicating a reduced ability to adapt to functions such as planning, organizing, and responding to change, which are directly linked to executive functions.
Some people are more cognitively flexible than others. It’s just the luck of the genetic draw in some ways, though we can improve our cognitive flexibility when we realize that we’re being inflexible.
Think of it this way: We’re cognitively flexible when we can start dinner, let the onions boil, text a friend, go back to making dinner without burning the onions, and then finish dinner while also talking to our spouse.
We’re also cognitively flexible when we switch communication styles from talking to a friend to a daughter to a coworker, or when we’re creative problem solvers—say, when you realize you don’t have onions to make the dinner you want, so you need a new plan.
It’s part of our executive function, which includes accessing memories and displaying self-control. Poor executive function is a hallmark of ADHD in both children and adults.
When we’re cognitively inflexible, we can’t focus on certain tasks, picking up our phones and mindlessly scrolling through social media, forgetting what we’re doing while we’re cooking dinner.
In adults, but especially in children, this cognitive inflexibility can wreak havoc on an individual’s ability to learn and perform tasks. Many neuroimaging studies suggest that ADHD is linked to atypical organization and impaired functional connectivity (FC) between brain networks.
Brain connectivity in children with ADHD tends to show disruptions globally and within subnetworks, less efficiency in long-range connections, and reduced segregation between the default mode network (DMN), which deals with self-reflection and thinking at rest, and other task-specific networks.
Scientists at the University of North Carolina (UNC) conducted a neuroimaging study to explore a neural activity that corresponds to “cognitive flexibility”, the brain’s ability to adapt to new information and switch between tasks or thoughts efficiently. This ability is essential for learning and development, especially in children. The study was published in Molecular Psychiatry.
The study analyzed differences in brain activity between 180 children with attention deficit hyperactivity disorder (ADHD) and 180 without the disorder.
The researchers observed a significant reduction in the neural flexibility in children with ADHD.
By examining brain activity at different levels, including the whole brain and specific subnetworks (brain areas that communicate to perform certain functions), the scientists noted that children with ADHD showed less variation in communication between these regions.
A significant reduction in whole-brain neural flexibility was observed in individuals with ADHD compared to DCD. Consistent with this finding, the researchers observed that the modules were significantly more stable in individuals with ADHD.
To further examine whether the observed reduction in neural flexibility in ADHD was driven by specific functional brain systems or was a general feature of the whole brain, neural flexibility at the network level was compared between individuals with ADHD and DCD.
Compared to DCD, individuals with ADHD exhibited a significant reduction in neural flexibility in all networks except the cingulo-opercular and cerebellar networks.
The cingulo-opercular network (CON) is an executive network in the human brain that regulates actions. The CON is composed of a set of functionally coupled regions in the dorsal anterior cingulate cortex (dACC), dorsomedial prefrontal cortex (dmPFC), anterior insula (AI), supramarginal gyrus (SMG), areas responsible for attention, focus, social behavior, and impulsivity.
Visualization of systems 1 (ventral and dorsal attention, upper row) and 2 (cingulo-opercular and frontoparietal, bottom row) on a glass brain. DACC, dorsal anterior cingulate cortex; laPFC, left anterior prefrontal cortex; AI, anterior insula; raPFC, right anterior prefrontal cortex; SupF, superior frontal gyrus; LP, lateral prefrontal cortex; vmPFC, ventromedial prefrontal cortex; dmPFC, dorsomedial prefrontal cortex; PHG, parahippocampal gyrus; ITC, inferior temporal cortex; MFG, middle frontal gyrus; IPL, intraparietal lobule; IFG, inferior frontal gyrus; STG, superior temporal gyrus; FEF, frontal eye fields; IPS, intraparietal sulcus; dlPFC, dorsolateral prefrontal cortex; precun, precuneus. Image: Lidan Freedman et al. NeuroImage: Clinical
Additionally, the study examined the influence of ADHD medication on neural flexibility. A total of 46 individuals with ADHD were given medication.
Children with ADHD who were on medication showed increased neural flexibility compared to those who were not on medication, and their neural flexibility levels were similar to those of typically developing children. These findings suggest that medication may improve the brain organization of children with ADHD, promoting greater mental adaptability.
Finally, the researchers evaluated the hypothesis that neural flexibility could serve as a biomarker to differentiate children with ADHD from DCD. A biomarker is a measurable characteristic, such as a molecule, gene, or brain pattern, that indicates biological processes, health conditions, or response to treatment.
The researchers found that neural flexibility could significantly predict the presence of ADHD and the severity of symptoms. Using predictive models, neural flexibility was 77% accurate in differentiating children with ADHD from those without ADHD and was able to predict ADHD severity based on clinical symptom scales.
These findings suggest that neural flexibility may be a promising tool for both diagnosis and monitoring treatment response in children with ADHD, offering a new perspective for understanding and treating the disorder.
Successful prediction of ADHD status and severity using neural flexibility. (a) Precision, sensitivity, specificity, and AUC (accuracy) for the ADHD classification model, and (b) spatial distribution of the 24 most predictive regions using ranked importance scores. (c) Scores between analyzed groups, and (d) scatter plots comparing severity scores based on neural flexibility. (e) spatial distribution of the 28 most predictive regions using ranked importance scores.
These findings provide new insights into how neural flexibility impairments affect cognition and behavior in children with ADHD. The study highlights the role of neural flexibility as a potential tool for diagnosis and for creating personalized interventions aimed at improving cognitive flexibility and reducing symptoms of the disorder.
READ MORE:
Altered neural flexibility in children with attention-deficit/hyperactivity disorder.
Yin W, Li T, Mucha PJ. et al.
Mol Psychiatry 27, 4673–4679 (2022).
Abstract:
Attention-deficit/hyperactivity disorder (ADHD) is one of the most common neurodevelopmental disorders of childhood and is often characterized by altered executive functioning. Executive function has been found to be supported by flexibility in dynamic brain reconfiguration. Thus, we applied multilayer community detection to resting-state fMRI data in 180 children with ADHD and 180 typically developing children (TDC) to identify alterations in dynamic brain reconfiguration in children with ADHD. We specifically evaluated MR derived neural flexibility, which is thought to underlie cognitive flexibility, or the ability to selectively switch between mental processes. Significantly decreased neural flexibility was observed in the ADHD group at both the whole brain (raw p = 0.0005) and sub-network levels (p < 0.05, FDR corrected), particularly for the default mode network, attention-related networks, executive function-related networks, and primary networks. Furthermore, the subjects with ADHD who received medication exhibited significantly increased neural flexibility (p = 0.025, FDR corrected) when compared to subjects with ADHD who were medication naïve, and their neural flexibility was not statistically different from the TDC group (p = 0.74, FDR corrected). Finally, regional neural flexibility was capable of differentiating ADHD from TDC (Accuracy: 77% for tenfold cross-validation, 74.46% for independent test) and of predicting ADHD severity using clinical measures of symptom severity (R2: 0.2794 for tenfold cross-validation, 0.156 for independent test). In conclusion, the present study found that neural flexibility is altered in children with ADHD and demonstrated the potential clinical utility of neural flexibility to identify children with ADHD, as well as to monitor treatment responses and disease severity.
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