Examination of neural activation patterns and neural connectivity during response inhibition tasks may help distinguish adolescents with ADHD from their unaffected siblings, two recent Dutch studies report.
Dysfunctional response inhibition is one of the key executive function impairments associated with ADHD. In these studies*, neural correlates of response inhibition and functional connectivity during response inhibition task completion were evaluated in adolescents with ADHD (n=185; mean age = 17.3 years), their unaffected siblings (n=111; mean age = 17.3 years) and healthy controls (n=124; mean age = 16.5 years). Response inhibition was assessed using the stop signal task; during completion of the task, functional MRI measurements of neural activation were taken; and functional connectivity was assessed using a psycho-physiological interaction analysis.
Stop-signal task reaction times were longer and more errors were made by adolescents with ADHD, compared with unaffected siblings† and controls‡. Adolescents with ADHD showed increased connectivity within the default mode network (DMN) compared with the other two groups, with stronger connectivity in the DMN correlated with ADHD severity. Siblings showed connectivity patterns similar to controls during successful response inhibition and to adolescents with ADHD during failed inhibition.
Furthermore, hypoactivation in the frontal-striatal and frontal-parietal networks was identified in both participants with ADHD and their unaffected siblings, compared with controls.
Researchers concluded that although adolescents with ADHD showed impaired response inhibition compared with unaffected siblings; the similar connectivity and hypoactivation patterns observed between these groups during response inhibition task completion support the familiar nature of the dysfunction.
*Participants were part of the NeuroIMAGE Dutch follow-up of the International MultiCenter ADHD Genetics (IMAGE) study
†Versus unaffected siblings: reaction times, β=-15.4, p=0.015; error rate, β=-1.8, p<0.013
‡Versus control: reaction times: β=-13.8, p=0.05; error rate: β=-2.5, p<0.001
- van Rooij D, Hoekstra PJ, Mennes M, et al. Distinguishing adolescents with ADHD from their unaffected siblings and healthy comparison subjects by neural activation patterns during response inhibition. Am J Psychiatry 2015; 172: 674-683.
- van Rooij D, Hartman CA, Mennes M, et al. Altered neural connectivity during response inhibition in adolescents with attention-deficit/hyperactivity disorder and their unaffected siblings. Neuroimage Clin. 2015; 7: 325-335.