Effects of the FITKids Randomized Controlled Trial on Cognitive Control and Conflict Monitoring in Children

Abstract

PURPOSE: We investigated the influence of a 9-month physical activity intervention (FITKids: NCT01619826, NCT01334359) on cognitive control and conflict monitoring. METHODS: Three hundred eight preadolescent children (8-9 years old) were randomized into an afterschool physical activity intervention (n=139) or a wait-list control group (n=169). The FITKids intervention occurred following every school day and provided a sum of 70-minutes of moderate-to-vigorous physical activity per session. All children completed a fitness assessment and a cognitive control task (i.e., flanker task) at pre- and post-test. Event-related brain potentials (ERPs) were recorded during flanker performance to determine neuroelectric underpinnings of frontally mediated changes in conflict monitoring (i.e., error-related negativity or ERN). RESULTS: Results revealed greater improvements in fitness from pre- to post-test for the intervention group (1.8 mL/kg/min; 5.4% change) compared to the control group (0.6 mL/kg/min; 2.1% change) [t(306)=2.3, p=0.02]. Further, increased performance was observed for the flanker task, requiring variable amounts of cognitive control, with greater change for the intervention group (9.3% accuracy; -8.5 omission errors, -2.0 omission error runs) compared to the control group (6% accuracy; -4.1 omission errors, -0.7 omission error runs) [F’s(1, 306)≥6.1, p’s≤0.02]. Additionally, results revealed larger ERN amplitude at post-test (-6.3 μV) compared to pre-test (-5.0 μV), only for the wait-list group [F’s(1, 306)≥9.6, p’s≤0.01] with no such change observed for the intervention group (pre-test: -5.7 μV; post-test: -5.7 μV) [F’s(1, 306)≤0.6, p’s≥0.46], suggesting greater cognitive efficiency in that no additional adjustments in neural indices of performance monitoring were observed to underlie improved performance at post-test. Lastly, a dose-response relation was observed for children in the intervention such that greater improvements in cardiorespiratory fitness were related to greater reductions in ERN amplitude (r=.20, p=0.02). CONCLUSIONS: These findings demonstrate that daily physical activity not only serves to improve fitness but also facilitates behavioral and functional neural processes associated with effective conflict monitoring in young children.