Related Experiment Video
Updated: Nov 11, 2025
Using Brain Activation nir-HEG/Q-EEG and Execution Measures CPTs in a ADHD Assessment Protocol
Published on: April 1, 2018
Relationship between GABA levels and task-dependent cortical excitability in children with
Ashley D Harris1, Donald L Gilbert2, Paul S Horn2
1Radiology, University of Calgary, Calgary, AB, Canada; Child and Adolescent Imaging Research Program, Alberta Children's Hospital Research Institute, University of Calgary, Calgary, AB, Canada; Hotchkiss Brain Institute, University of Calgary, Calgary, AB, Canada.
Objective:
Compared to typically developing (TD) peers, children with attention deficit hyperactivity disorder (ADHD) manifest reduced short interval cortical inhibition (SICI) in the dominant motor cortex measured with transcranial magnetic stimulation (TMS). This multimodal study investigates the inhibitory neurophysiology and neurochemistry by evaluating the relationship between SICI and γ-amino butyric acid (GABA+) levels, measured with magnetic resonance spectroscopy (MRS).
Methods:
Across two sites, 37 children with ADHD and 45 TD children, ages 8-12 years, participated. Single and paired pulse TMS to left motor cortex quantified SICI during REST and at times of action selection (GO) and inhibition (STOP) during a modified Slater-Hammel stop signal reaction task. MRS quantified GABA+ levels in the left sensorimotor cortex. Relationships between SICI and GABA+, as well as stopping efficiency and clinical symptoms, were analyzed with correlations and repeated-measure, mixed-models.
Results:
In both groups, higher GABA+ levels correlated with less SICI. In TD children only, higher GABA+ levels correlated with larger TMS motor evoked potentials (MEPs) at REST. In GO and STOP trials, higher GABA+ was associated with smaller MEP amplitudes, for both groups. Overall, GABA+ levels did not differ between groups or correlate with ADHD clinical symptoms.
Conclusions:
In children with higher motor cortex GABA+, motor cortex is less responsive to inhibitory TMS (SICI). Comparing the relationships between MRS-GABA+ levels and responses to TMS at REST vs. GO/STOP trials suggests differences in inhibitory neurophysiology and neurotransmitters in children with ADHD. These differences are more prominent at rest than during response inhibition task engagement.
Significance:
Evaluating relationships between GABA+ and SICI may provide a biomarker useful for understanding behavioral diagnoses.
More Related Videos
10:02Event Related Potentials ERPs and other EEG Based Methods for Extracting Biomarkers of Brain Dysfunction: Examples from Pediatric Attention Deficit/Hyperactivity Disorder ADHD
Published on: March 12, 2020
12:21Probing the Brain in Autism Using fMRI and Diffusion Tensor Imaging
Published on: September 12, 2011
