Effortful Control and Cortical Brain Structure in 5‐Year‐Old Children: Findings From the FinnBrain Birth Cohort Study

The aim of this study was to explore the associations between an aspect of self-regulation (SR), effortful control (EC) and cortical brain structure in 5-year-old children. Efficient EC is a predictor of many attributes and important outcomes in life, such as social-emotional functioning, finance, psychiatric and somatic health. The early brain correlates of EC are not widely studied, and a better understanding of them would aid in understanding how self-regulatory capacities emerge over development. Participants (N = 155) were a part of the FinnBrain Birth Cohort Study in Finland. T1-weighted brain magnetic resonance images were processed using FreeSurfer. The data were statistically analysed with a vertex-wise general linear model. At the age of 5 years, EC was assessed via parental report using The Children's Behaviour Questionnaire. We found positive associations between EC and cortical volume in the left supramarginal region and in the right inferior temporal region. We also found positive associations between EC and surface area on the left hemisphere in the superior parietal region. We extended the previous literature by shedding light on early structural brain correlates of EC in a large sample of typically developing 5-year-olds. The main results differed significantly from previous findings in older children. The results were only present with questionnaire- and not task-based evaluation of EC. Both questionnaire and task-based evaluations are required to consider different aspects of EC and SR. In addition, longitudinal studies are needed to better understand the neural underpinnings of SR throughout development.