Response Inhibition Deficits and Altered Motor Network Connectivity in the Chronic Phase of Pediatric Traumatic Brain Injury

Poor response inhibition is a hallmark of pediatric traumatic brain injury (TBI). We assessed motor response inhibition by measuring commission error rates on Simple (minimized cognitive demands) and Motivation (monetary reward) Go/No-Go tasks, comparing 17 children with chronic TBI (>1 year post-injury) and 14 matched, uninjured peers. Using resting state functional magnetic resonance imaging (fMRI), we examined between-group differences in whole-brain intrinsic connectivity of the motor network as derived from the averaged time course of bilateral primary motor cortex seeds, to identify regions of interest (ROIs) for brain-behavior correlations. Independent sample t tests compared Go/No-Go performance and connectivity at the ROI level. Pearson correlations examined relationships between intrinsic connectivity at the ROI level and Go/No-Go performance. Adolescents with TBI showed poorer performance on Simple and Motivation Go/No-Go tasks compared with controls. In whole-brain contrasts, adolescents with TBI showed significantly reduced functional connectivity between the motor network and voxels within the left caudate. Furthermore, in ROI analyses, the group with TBI had significantly lower connectivity between the motor network and left caudate and numerically lower connectivity between the motor network and right caudate. In adolescents with TBI, lower motor network to left caudate connectivity correlated with poorer Simple task performance; lower motor network to right caudate connectivity correlated with poorer Simple and Motivation task performance. No significant brain-behavior relationships existed among controls. These results are consistent with previous pediatric TBI literature and suggest that disrupted intrinsic connectivity of a corticostriatal motor network may contribute to response inhibition deficits.