To account appropriately for multiple comparisons over the eight traits in our analysis, we first examined the degree of independence between each trait. We generated an 8 × 8 correlation matrix based on the Pearson’s correlation between all pair-wise combinations of the mean volumes of each structure in the QTIM study. Using the matSpD software38 we found that the effective number of independent traits in our analysis was 7. We therefore set a significance criteria threshold of P < (5 × 10−8/7) = 7.1 × 10−9.
