Neural Correlates of Inhibitory Control in Children: Evidence Using MRI and fNIRS.

Inhibitory control (IC) develops in stages from infancy through adolescence and is associated with numerous developmental disorders and learning outcomes. This study examined how neural architecture - in particular myelination - underlies brain activation patterns observed during IC tasks in a sample of 28 children aged 4-10 years old. IC was observed using reaction times during go/no-go and flanker IC tasks. Myelination was measured using quantitative longitudinal relaxation rate (R1) mapping obtained from selected white matter regions of interest (ROIs). Brain activation was defined as task-related changes in hemoglobin oxygenation as measured by functional near-infrared spectroscopy (fNIRS) averaged within ROIs. Results indicated that myelination in ROIs was higher in older children and fNIRS activation in frontal channels was significantly and positively associated with go/no-go mean reaction time. Myelination in the corona radiata and superior longitudinal fasciculus was positively associated with frontal fNIRS activation, while myelination was negatively associated with go/no-go and flanker mean reaction times across white matter ROIs. Overall, significance level notably varied across models. Independently of inhibitory control constructs, these regions may be of interest in future structure-function studies across development.