Related Experiment Video
Updated: Apr 12, 2026
Comparing Eye-tracking Data of Children with High-functioning ASD, Comorbid ADHD, and of a Control Watching Social Videos
Published on: December 7, 2018
Motor Circuit Anatomy in Children with Autism Spectrum Disorder With or Without Attention Deficit Hyperactivity
Rajneesh Mahajan1,2,3, Benjamin Dirlikov1, Deana Crocetti1
1From Center for Neurodevelopmental and Imaging Research, Kennedy Krieger Institute, Baltimore, Maryland.
Insights
Autism spectrum disorder (ASD) is linked to altered brain structure in motor regions. These changes, particularly in the somatosensory cortex, may affect motor skills and differ between children with and without comorbid attention deficit hyperactivity disorder (ADHD).
Area of Science:
- Neuroscience
- Developmental Psychology
- Pediatrics
Background:
- Autism spectrum disorder (ASD) and attention deficit hyperactivity disorder (ADHD) are common neurodevelopmental conditions.
- Motor skill deficits are frequently observed in children with ASD.
- The neurobiological underpinnings of motor impairments in ASD, especially concerning comorbid ADHD, require further investigation.
Purpose of the Study:
- To investigate cortical morphology in frontal-parietal regions associated with motor function in children with ASD.
- To explore the relationship between brain morphology, autism severity, and motor skills.
- To examine the impact of comorbid ADHD on these morphological and functional associations.
Main Methods:
- Utilized high-resolution 3T MPRAGE MRI scans for 126 school-age children (ASD only, ASD with ADHD, typically developing).
- Analyzed cortical morphology (gray matter volume, surface area, cortical thickness) in the precentral gyrus (M1), postcentral gyrus (S1), and inferior parietal cortex (IPC).
- Assessed motor functions, including praxis and manual dexterity, and correlated them with neuroimaging findings.
Main Results:
- Children with ASD exhibited increased gray matter volume and surface area in motor-related regions (M1, S1, IPC).
- Specific increases in S1 gray matter and right M1 volume were noted in ASD without ADHD.
- Increased left IPC surface area was observed in all children with ASD. Impaired praxis in ASD with ADHD correlated with increased right S1 gray matter volume.
- Differential relationships between S1 gray matter volume and manual dexterity were found between ASD with and without ADHD groups.
Conclusions:
- ASD is associated with abnormal morphology in cortical circuits critical for motor control and learning.
- Anomalous overgrowth in these regions, particularly S1, may contribute to motor skill impairments in ASD.
- Distinct morphological and functional patterns exist between children with ASD with and without ADHD, highlighting the influence of comorbid ADHD.
Abstract:
This study examined the morphology of frontal-parietal regions relevant to motor functions in children with autism spectrum disorder (ASD) with or without attention deficit hyperactivity disorder (ADHD). We also explored its associations with autism severity and motor skills, and the impact of comorbid ADHD on these associations. Participants included 126 school-age children: 30 had ASD only, 33 had ASD with ADHD, and 63 were typically developing. High resolution 3T MPRAGE images were acquired to examine the cortical morphology (gray matter volume, GMV, surface area, SA, and cortical thickness, CT) in three regions of interest (ROI): precentral gyrus (M1), postcentral gyrus (S1), and inferior parietal cortex (IPC). Children with ASD showed abnormal increases in GMV and SA in all three ROIs: (a) increased GMV in S1 bilaterally and in right M1 was specific to children with ASD without ADHD; (b) all children with ASD (with or without ADHD) showed increases in the left IPC SA. Furthermore, on measures of motor function, impaired praxis was associated with increased GMV in right S1 in the ASD group with ADHD. Children with ASD with ADHD showed a positive relationship between bilateral S1 GMV and manual dexterity, whereas children with ASD without ADHD showed a negative relationship. Our findings suggest that (a) ASD is associated with abnormal morphology of cortical circuits crucial to motor control and learning; (b) anomalous overgrowth of these regions, particularly S1, may contribute to impaired motor skill development, and (c) functional and morphological differences are apparent between children with ASD with or without ADHD.
Related Concept Videos
01:30Attention-Deficit/Hyperactivity Disorder
Diagnostic Criteria and Symptoms
To diagnose ADHD, symptoms must manifest before age 12 and be evident across multiple settings....
01:19Autism Spectrum Disorder
These core symptoms manifest differently among individuals, ranging from mild to severe. The disorder's complexity extends beyond its clinical presentation, encompassing a diverse range of biological, cognitive, and sociocultural influences.
01:26Modeling in Therapy
Participant Modeling
Participant modeling involves therapists demonstrating calm and effective behaviors in...
01:25Neural Circuits
Neuronal pools are collections of nerve cells with similar functions and interact through chemical and electrical signals. These pools include both interneurons (the central neural circuit nodes that...
01:18Hierarchy of Motor Control