Table 4.

Summary of parallel mediation analyses of race-related effects on GMV accounting for adversity.

Brain Region	Total Effect (c)	p-value	Total Indirect Effect (ab)	p-value	Direct Effect (c’)	p-value	Percentage Mediated
Caudal anterior cingulate+	−0.17	< .001	−0.04	0.006	−0.13	< .001	26.04%
Caudal middle frontal+	−0.29	< .001	−0.09	< .001	−0.20	< .001	30.58%
Lateral orbitofrontal+	−0.45	< .001	−0.03	0.034	−0.41	< .001	7.40%
Medial orbitofrontal	−0.03	0.333	−0.02	0.287	−0.01	0.748	-
Pars opercularis	−0.31	< .001	0.01	0.613	−0.32	< .001	2.57%
Pars triangularis+	0.13	< .001	0.06	< .001	0.08	0.02	42.42%
Pars orbitalis+	−0.19	< .001	−0.04	0.008	−0.15	< .001	21.88%
Rostral anterior cingulate	−0.29	< .001	−0.03	0.098	−0.27	< .001	8.93%
Rostral middle frontal	0.02	0.597	−0.09	< .001	0.10	0.001	-
Superior frontal+	−0.20	< .001	−0.10	< .001	−0.10	0.003	50.76%
Frontal pole+	−0.19	< .001	−0.04	0.006	−0.15	< .001	23.28%
Insula	0.05	0.116	0.02	0.155	0.02	0.501	-
Hippocampus	−0.12	< .001	−0.01	0.765	−0.11	< .001	4.27%
Amygdala	−0.14	< .001	−0.01	0.582	−0.13	< .001	6.67%

Note: Gray matter volume (GMV) estimated from residuals of linear mixed effects models that included age, gender, scanner, and family relatedness (i.e., the isolated race-related effect). Percentage mediated is calculated by ab/c * 100.

⁺Symbol indicates model met criteria for partial or full mediation. Percentage mediated omitted for regions in which no significant total effect was observed.