Other covariates: Age (months), sex, race, income, parental education and BMI levels (defined as lean, overweight or obese based on CDC guidelines. Note underweight children were excluded.

Statistical Analysis

Multivariate linear regression was used to assess the relationship between PPS and fMRI activity in the MID task. The following additional covariates were included in all analysis; age, sex, race, household income , parental education and scanner-type (in-scanner motion was not found to be a significant predictor and was thus not included in the final model). The final minimum model was as follows:
m <- lm(scale(MID) ~ scale(age_months) + sex + income_int + race_wbho + p_edu + device1 + scale(pps_sum), data=MID, na.action=na.omit)
False discovery rate (FDR) methods \cite{y1995} were used to correct cortical results for multiple comparisons.

Results

Mean Activation across the Cortex

A plot of mean activation per region, averaged across 2131 subjects is reported below (Figure \ref{709749}). Of note, subjects with activation greater than 3 standard deviations were excluded.