Supplementary material: Brain and behavior associations of executive functions: a global OCD study

The ridge plots attached here accompany Figures S4, S5, S6, S12 and S13 of the supplement to Brain and behavior associations of executive functions: a global OCD study (Rodrigues et al., 2026). These are the full results of Bayesian multilevel models run using the Regional Bayesian Analysis toolbox (RBA; Chen et al., 2019), depicting associations between structural brain measures and performance on the Tower of London (TOL) planning task and the visuospatial N-back (VSWM) task. Cortical analyses were parcellated into 210 regions of interest using the Brainnetome atlas (Fan et al., 2016), while subcortical gray matter volume was derived from 14 structures using the native FreeSurfer subcortical segmentation (aseg) atlas. Results are presented across three structural modalities: subcortical gray matter volume (GMV), cortical thickness (CTh), and surface area (SA), for the following effects of interest: [Task = TOL accuracy], [Task = TOL response time], and [Task = N-back accuracy].

P+ values denote the posterior probability that a given brain-behavior association is positive (i.e., that greater structural measure is associated with better task performance). We used the guidelines proposed by Chen et al. (2019) to infer the credibility of evidence: a P+ of >0.90 or <0.10 is taken as moderate evidence, >0.95 or <0.05 as strong evidence, and >0.975 or <0.025 as very strong evidence. In the whole-sample ridgeplots (Figures S12-13), posterior distributions shifted to the right of the zero-effect line indicate positive associations, while distributions shifted to the left indicate negative associations. Red color reflects positive associations and blue reflects negative associations, with color intensity scaling with evidence strength; grey indicates no credible evidence.

To interpret the group-difference ridgeplots (Figures S4–S6), pairwise comparisons are presented as Group 1 vs Group 2. Posterior distributions to the right of the zero-effect line represent regions in which individuals in Group 1 show credible evidence for a steeper positive brain–behavior association than individuals in Group 2; distributions to the left of this line indicate the reverse. Red color reflects a more positive brain-behavior association in Group 1, blue reflects a more positive brain-behavior association in Group 2, and grey indicates no credible evidence of a group difference. Three pairwise comparisons are shown: healthy controls (HC) vs OCD, HC vs siblings, and OCD vs siblings.

Brainnetome atlas region labels can be retrieved at https://atlas.brainnetome.org/bnatlas.html. FreeSurfer subcortical segmentation labels can be retrieved at https://surfer.nmr.mgh.harvard.edu/fswiki/FreeSurferVersion3.

Legends:

Figure S4. Group-differences in association beetwen subcortical gray matter volume and task performance. Posterior distributions illustrate the group difference in the association between the subcortical gray volume and the cognitive measures, with evidence strength indicated by the color scale (P+). Left: red reflects a more positive brain-behavior association of the HC group and blue reflects a more positive brain-behavior association in the OCD group; Middle: red reflects a more positive brain-behavior association of the HC group and blue reflects a more positive brain-behavior association in the Sibling group; Right: red reflects a more positive brain-behavior association of the OCD group and blue reflects a more positive brain-behavior association in the Sibling group. The credibility of evidence is classified as very strong (P+ > 0.975 or < 0.025), strong (0.975 ≥ P+ > 0.95 or 0.05 > P+ ≥ 0.025), and moderate (0.95 ≥ P+ > 0.90 or 0.10 > P+ ≥ 0.05).

Figure S5. Group-differences in association between cortical thickness volume and task performance. Posterior distributions illustrate the group difference in the association between the cortical thickness and the cognitive measures, with evidence strength indicated by the color scale (P+). Left: red reflects a more positive brain-behavior association of the HC group and blue reflects a more positive brain-behavior association in the OCD group; Middle: red reflects a more positive brain-behavior association of the HC group and blue reflects a more positive brain-behavior association in the Sibling group; Right: red reflects a more positive brain-behavior association of the OCD group and blue reflects a more positive brain-behavior association in the Sibling group. The credibility of evidence is classified as very strong (P+ > 0.975 or < 0.025), strong (0.975 ≥ P+ > 0.95 or 0.05 > P+ ≥ 0.025), and moderate (0.95 ≥ P+ > 0.90 or 0.10 > P+ ≥ 0.05).

Figure S6. Group-differences in association between surface area and task performance. Posterior distributions illustrate the group difference in the association between the surface area and the cognitive measures, with evidence strength indicated by the color scale (P+). Left: red reflects a more positive brain-behavior association of the HC group and blue reflects a more positive brain-behavior association in the OCD group; Middle: red reflects a more positive brain-behavior association of the HC group and blue reflects a more positive brain-behavior association in the Sibling group; Right: red reflects a more positive brain-behavior association of the OCD group and blue reflects a more positive brain-behavior association in the Sibling group. The credibility of evidence is classified as very strong (P+ > 0.975 or < 0.025), strong (0.975 ≥ P+ > 0.95 or 0.05 > P+ ≥ 0.025), and moderate (0.95 ≥ P+ > 0.90 or 0.10 > P+ ≥ 0.05).

Figure S12. Associations between cortical thickness and task performance. Posterior distributions illustrate the relationship between the cortical thickness of each region of interest and the cognitive measures, with evidence strength indicated by the color scale (P+): red reflects positive associations and blue reflects negative associations. The credibility of evidence is classified as very strong (P+ > 0.975 or < 0.025), strong (0.975 ≥ P+ > 0.95 or 0.05 > P+ ≥ 0.025), and moderate (0.95 ≥ P+ > 0.90 or 0.10 > P+ ≥ 0.05).

Figure S13. Associations between surface area and task performance. Posterior distributions illustrate the relationship between the surface of each region of interest and the cognitive measures, with evidence strength indicated by the color scale (P+): red reflects positive associations and blue reflects negative associations. The credibility of evidence is classified as very strong (P+ > 0.975 or < 0.025), strong (0.975 ≥ P+ > 0.95 or 0.05 > P+ ≥ 0.025), and moderate (0.95 ≥ P+ > 0.90 or 0.10 > P+ ≥ 0.05).