Aim: To investigate sex differences in the association between cortical thickness and behavioral inhibition of 9-10 years old American children.
Materials and methods: This cross-sectional investigation used data from the Adolescent Brain Cognitive Development (ABCD) study. Baseline ABCD data of 10249 American children between ages 9 and 10 were analyzed. The independent variable was cortical thickness measured by structural brain magnetic resonance imaging (sMRI). The primary outcome, behavioral inhibition, was measured based on the behavioral inhibition system (BIS), and behavioral approach system (BAS). Sex was the moderator. Age, race, ethnicity, socioeconomic status indicators, and intracranial volume were covariates.
Results: In the overall sample, high cortical thickness was not associated with behavioral inhibition in children. Sex showed a statistically significant interaction with cortical thickness's effect on children's behavioral inhibition, net of all confounders. The interaction indicated a statistically stronger positive effect of high cortical thickness on male behavioral inhibition compared to female children.
Conclusion: Cortical thickness is a determinant of behavioral inhibition for male but not female American children. Male but not female children show better behavioral inhabitation at higher levels of cortical thickness.
Keywords: behavioral inhibition; children; cortical thickness; magnetic resonance imaging (MRI); sex.