The brain systems that help children maintain focus appear to function on a single, shared spectrum, regardless of whether the child has an attention disorder. A large new study shows that neurological markers of attentional abilities do not differ between children with and without a diagnosis of attention-deficit hyperactivity disorder. This study was published in the *Journal of Attenders*.
Attention is not simply an “all or nothing” quality. People have varying levels of what psychologists call “inhibitory attentional control.” This is a cognitive skill that allows you to focus on a specific task or stimulus while eliminating surrounding distractions.
This particular type of attention deficit is very common in neurodevelopmental conditions such as ADHD. Medical researchers want to understand the underlying brain physiology because this decline in attention can affect academic performance and daily life. This knowledge can help guide clinical therapy for those with the greatest challenges.
Traditionally, psychiatric research has relied heavily on categorical diagnostic groupings. This approach assumes that people with conditions like ADHD are fundamentally different from people without them. Although this traditional method helps physicians efficiently communicate treatment options, it can mask the large variation that exists within a single diagnostic group.
In contrast, modern frameworks propose studying human behavior along a continuous spectrum. In this model, cognitive abilities and cognitive impairments are seen as traits that are shared by everyone to varying degrees. New findings provide strong support for this dimensional approach to investigating neurodevelopmental outcomes.
To explore this concept, scientists use a tool called functional magnetic resonance imaging. This technology, commonly known as fMRI, measures brain activity by detecting subtle changes related to blood flow. When neurons are active, they require more oxygen, which is carried by the blood.
Specifically, scientists are looking at functional connections that map how different regions of the brain communicate and synchronize their resting activity. When multiple brain regions are activated systematically, complex functional networks are formed. These networks manage everything from processing visual information to managing complex movements.
Previous studies have linked specific brain networks to attention skills, while other lines of research have linked other networks to ADHD diagnoses. However, it remained unclear whether receiving a formal ADHD diagnosis changes the fundamental relationship between a person’s attention and brain connectivity. Answering this question will help psychologists determine the most effective way to model cognitive impairment.
Kelsey Harkness, a researcher at the University of Calgary Alberta Children’s Hospital Research Institute, led a new study to fill this gap. Her team wanted to test whether children with ADHD exist along the same continuum of brain-behavior associations as undiagnosed children. They approached the investigation from a purely analytical perspective to avoid past biases.
The researchers used information from the Adolescent Brain Cognitive Development Database. This is a large-scale, long-term national project that will collect neuroimaging and psychological data from children across the United States. This database is intended to provide a highly representative sample of the country’s youth for scientific research.
For this large-scale study, Harkness and her colleagues analyzed data from just over 7,000 children aged 9 or 10. Within this group, there were nearly 500 children currently diagnosed with ADHD. The remaining children served as the baseline control group.
To measure inhibitory control of attention, subjects completed a standardized assessment called the flanker task. During this test, children must identify the direction of the central arrow on the screen while ignoring surrounding arrows pointing in the same or opposite direction. The test determines your score based on both accuracy and reaction time.
The research team also analyzed resting-state fMRI scans of all the children involved. Unlike traditional fMRI studies, where subjects perform academic tasks in a scanner, resting-state scans observe a person’s brain while they are simply lying down and awake. This allows the scanner to record the brain’s default communication patterns.
Task-based imaging can be complex depending on the extent to which participants perform the required tests within the machine. Children who are anxious about the noisy, confined space of the MRI scanner may score lower and have skewed functional connectivity data. Resting-state scans minimize this performance pressure and allow scientists to identify unique communication pathways within the nervous system.
Data analysis revealed independent patterns linking resting-state brain connectivity to both attention scores and diagnostic status. For example, children’s performance on flanker tasks was correlated with connectivity in specific cortical circuits, such as the visual baseline network. It also matched areas associated with sensory and motor processing, particularly physical movements of the mouth and hands.
Separately, being diagnosed with ADHD was associated with connectivity patterns in entirely different brain regions. These connections primarily involve ventral attention and auditory networks. These systems typically help the brain adapt to unexpected sounds and new stimuli in the surrounding environment.
When researchers compared the networks associated with attention scores with those associated with ADHD, they found no overlap. The differences in brain connectivity associated with an ADHD diagnosis were completely different from the connectivity differences associated with basic attention skills. This difference suggests that different behavioral traits rely on distinct neural pathways.
Most importantly, the research team tested whether an ADHD diagnosis altered the relationship between children’s attention scores and brain connectivity. The results of this particular test were not statistically significant.
This lack of interaction means that the neural wiring associated with inhibitory control appears essentially identical in both groups. Children with ADHD who score low on attention tests have the same relevant brain connections as neurotypical children who score low.
This finding supports the idea that attentional abilities exist on a single continuous spectrum for all children. This suggests that researchers can study the basic cognitive characteristics of entire populations, rather than isolating individuals into strict diagnostic categories. This framework is fully consistent with the transdiagnostic model of mental health.
The discovery that distinct brain networks are associated with ADHD and attention also provides new insights into ADHD itself. This suggests that the differences in functional connectivity seen in children with ADHD may be caused by environmental factors or other symptoms. Diagnostic brain markers can be influenced by a wide range of developmental variables, as well as the ability to filter out distractions.
Despite the large sample size, the researchers noted several limitations to the current analysis. The study included only 9- and 10-year-old children, limiting the ability to generalize the results to younger children, teens, or adults.
Attention and brain networks develop and change rapidly as children grow. Certain networks become more robust during adolescence, while others shrink. Future developmental studies should follow participants across different age groups to see if this spectrum of unified attention is consistent throughout the human lifespan.
The research team also relied on a single computer assessment, the Flanker Task, to measure inhibitory control. Different types of attention tasks often involve slightly different brain networks. Using multiple assessments in combination may provide a more comprehensive picture of children’s cognitive function in future projects.
Finally, in this study, we extensively computed functional connectivity across a predefined large-scale cortical network. This macro-level perspective prevented the researchers from examining the influence of smaller, deeper brain structures. Aggregating the data into 12 comprehensive networks simplifies analysis but obscures detailed neurological mapping.
Deep regions such as the thalamus and striatum are known to play a role in controlling attention. It is also often a pharmacological target for stimulant treatments prescribed to children with hyperactivity. Future studies that look at the brain at finer spatial scales may reveal further details about the physiology of these states.
Ultimately, knowing exactly how cognitive impairment is related to brain structure will help medical professionals develop highly individualized interventions. By viewing attention as a continuum rather than a strictly binary trait, scientists hope to promote better long-term outcomes for all patients. Expanding these transdiagnostic frameworks has the potential to redefine how developmental disorders are diagnosed and treated in the future.
The study, “Relationship between inhibitory control of attention and fMRI functional connectivity with and without ADHD,” was authored by Kelsey Harkness, Matthias Wilms, Kate J. Godfrey, Signe Bray, and Kara Murias.
