Table 3.

Heritability of global and hemispheric phenotypes

CS trait	h2± SE	p value	Covariate variancea
Average depth (left and right)	0.56 ± 0.11	2.9 × 10−8	8%
Average length (left and right)	0.66 ± 0.12	1.2 × 10−9	4%
Left average depth	0.59 ± 0.09	10−7	6%
Right average depth	0.41 ± 0.11	10−5	6%
Left average length	0.47 ± 0.12	5 × 10−6	4%
Right average length	0.60 ± 0.12	3 × 10−7	3%

Global phenotypes were calculated by averaging CS measurements from both hemispheres; hemispheric phenotypes were calculated by averaging measurements from each hemisphere separately.

^aVariance explained by demographic covariates: age, age², sex, age × sex, and age² × sex, which were included in all genetic analyses.