Adult ADHD
Visual Abstract
Toward systems neuroscience of ADHD: a meta-analysis of 55 fMRI studies
Samuele Cortese, M.D., Ph.D., Clare Kelly, Ph.D., Camille Chabernaud, Ph.D., Erika Proal, Ph.D., Adriana Di Martino, M.D., Michael P. Milham, M.D., Ph.D., and F. Xavier Castellanos, M.D.
Summarized by:
April 22, 2023
study source
Am J Psychiatry
Oct 2012
🧠
With functional MRI, scientists can see differences in brain activity in those with ADHD.
📚
This meta-analysis collected data from 55 studies to see what differences can be found in the brains of those with ADHD.
💡
They found that ADHD affects areas throughout the brain, including focus, memory, and vision centers.
How does ADHD affect the brain? We know that ADHD can affect how we behave, how we plan, and how we process information. Can it also affect activity within our brain?
Through an imaging technique called functional MRI, researchers and doctors can see which parts of the brain are activated differently in those with ADHD.
Toward systems neuroscience of ADHD: a meta-analysis of 55 fMRI studies
Study Quote
The authors performed a comprehensive meta-analysis of task-based functional MRI studies of attention deficit hyperactivity disorder (ADHD).
Method
Researchers collected 55 studies that used functional MRI to study ADHD brains while participants were asked to perform tasks.
They conducted a meta-analysis, which is a type of study that combines data from multiple studies to find better answers.
What is a meta-analysis?
Study Quote
The authors searched PubMed, Ovid, EMBASE, Web of Science, ERIC, CINAHAL, and NeuroSynth for studies published through June 30, 2011. Significant differences in brain region activation between individuals with ADHD and comparison subjects were detected using activation likelihood estimat...
Show More
Results
Researchers found that certain parts of the brain were more active in children with ADHD, and others were less active.
While our knowledge of the brain only scratches the surface of its complexity, we do know enough to understand which areas correspond to which functions.
With this information, scientists can see which brain functions are more or less active in those with ADHD.
Children with ADHD show more activity in the daydreaming, sensing, and movement regions of their brains. This is consistent with the attention deficit and hyperactivity symptoms of ADHD in children.
They also have less activity in the brain's parts responsible for executive function and attention.
These are brain functions that are typically lacking in those with ADHD.
The following areas were shown to be significantly different in activation levels in the brains of children with ADHD compared to their peers on fMRI scans.
The data in adults showed that adults with ADHD had less activity in the parts of the brain responsible for following goals and for their working memory. This is consistent with the challenges that some adults with ADHD have with performing long, complex tasks requiring deep focus.
They also had more activity in the parts of the brain responsible for visual thinking, visual learning, and daydreaming.
The following areas were shown to be significantly different in activation levels in the brains of adults with ADHD compared to other adults on fMRI scans.
These differences are consistent with the defining symptoms of ADHD. For example, individuals with ADHD often have trouble following goals, their working memory, and being present during activities and conversations:
The symptoms above are the key symptoms used to define and diagnose ADHD. Screening and diagnostic testing for ADHD often involves question that seek to find out whether a person has a sufficient number of the symptoms listed above to qualify for an ADHD diagnosis. These are adapted from the DSM-5.
Study Quote
Fifty-five studies were included (39 for children and 16 for adults). In children, hypoactivation in ADHD relative to comparison subjects was observed mostly in systems involved in executive function (frontoparietal network) and attention (ventral attentional network). Significant hypera...
Show More
Conclusions
The authors concluded that there are many parts of the brain affected by ADHD. ADHD affects activity levels throughout the areas responsible for how we think and how we sense the world.
They also noted that earlier studies were focused on the prefrontal cortex, which is the part of the brain responsible for executive function.
What is executive function?
This study builds upon earlier studies by providing insights into how ADHD affects a broader array of brain areas and functions.
Study Quote
A growing literature provides evidence of ADHD-related dysfunction in multiple neuronal systems involved in higher-level cognitive functions but also in sensorimotor processes, including the visual system, and in the default network. This meta-analytic evidence extends early models of AD...
Show More