To determine whether FH density predicted BOLD response in regions that reliably activated to SWM relative to vigilance, the average activations for 15 of these 19 clusters were entered as dependent variables for hierarchical regressions performed in SPSS 14.0 (Chicago, IL). The right cerebellar tonsil cluster was excluded as a statistical outlier (see above). Three other clusters (left cerebellar tonsil, and left and right precentral motor cortices) were not entered into the equation because FH effects were not expected in these regions. Bulk motion in the roll and pitch directions were included as covariates, and FH density was entered on the second step. The presence of conduct disorder was not related to independent or dependent variables, and mothers’ education was related to FH but not activation, and therefore not included. Bonferroni correction was applied, and regressions were considered significant at α ≤ 0.003.
