Association between neuroticism and brain-wide structural outcomes: Mediation by vascular and mental conditions

Figures

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  Figure 1.. Brain-wide association between neuroticism and imaging-derived phenotypes (IDPs) by structural group. T statistics for the linear regression between neuroticism and brain-wide IDPs. Red dashed line indicates the Bonferroni threshold (1,747 tests, p = 2.86 × 10−5, T statistics = ±4.18) and blue dashed line indicated the False Discovery rate threshold (1,747 tests, p = 0.007, T statistics = ±2.70). See Supplementary Table S5 for regression coefficients and 95% confidence intervals. FA, ‘fractional anisotropy’; ICVF, ‘intra-cellular volume fraction’; ISOVF, ‘isotropic volume fraction’; OD, ‘orientation dispersion’; CSF, ‘cerebrospinal fluid’.

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  Figure 2.. Associations between neuroticism and white matter microstructure indices across white matter tract regions. aStructures with only a global measure (left and right hemisphere estimates are duplicated). Asterisks indicate Bonferroni-adjusted significant associations (p < 2.86 × 10−5); squares indicate FDR-adjusted significance at the same threshold (p < 0.007). FA, ‘Fractional Anisotropy’; λax, ‘Axial Diffusivity’; λrad, ‘Radial Diffusivity’; MD, ‘Mean Diffusivity’; ICVF, ‘Intra-Cellular Volume Fraction’; ISOVF, ‘Isotropic Volume Fraction’; OD, ‘Orientation Dispersion’.

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  Figure 3.. Total effect of neuroticism on significant imaging-derived phenotypes (IDPs) and indirect effects mediated by preselected health conditions. Light purple bars represent the total effect, dark purple bars indicate significant (Bonferroni-adjusted) indirect (mediating) effects, and grey bars denote insignificant (Bonferroni-adjusted) or directionally inconsistent indirect (mediating) effects. See Supplementary Table S2 for regression coefficients and mediation proportions. CV, ‘Cortical Volume’; CSA, ‘Cortical Surface Area’; CT, ‘Cortical Thickness’; subCV, ‘Subcortical Volume’; G/W, ‘Grey-White Matter Contrast’; FA, ‘Fractional Anisotropy’; λax, ‘Axial Diffusivity’; λrad, ‘Radial Diffusivity’; MD, ‘Mean Diffusivity’; ICVF, ‘Intra-Cellular Volume Fraction’; ISOVF, ‘Isotropic Volume Fraction’; OD, ‘Orientation Dispersion’.

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  Figure 4.. Inverse-variance weighted (IVW) estimates for the bidirectional Mendelian randomization. aOnly one genome-wide significant and independent SNP identified, but it was not available in the outcome GWAS; bNo SNP remained after harmonization due to all being palindromic with minor allele frequency > 0.42 or unknown; cNo genome-wide significant and independent SNPs identified for use as IVs. IV, instrumental variable; SNP, single nucleotide polymorphism; GWAS, ‘genome-wide association studies’; ‘F_DKT’, ‘derived from FreeSurfer DKT atalas’; ‘F_w’, ‘derived from FreeSurfer Desikan white atlas’; ‘F_w’, ‘derived from FreeSurfer Desikan pial atlas’. See Supplementary Tables S8 and Table S10 for regression coefficients and 95% confidence intervals.