Table 2.

Association of age and sex with cortical indices

Region	Age F	Age p	Sex T	Sex p	R 2 (%)
Intrinsic curvature
Frontal	38.42	1.03 × 10 −7 ***	−3.42	7.54 × 10 −4 *	24
Parietal	38.23	7.67 × 10 −8 ***	−0.50	0.62	16
Temporal	19.77	1.89 × 10 −4 **	−2.14	0.03	15
Occipital	2.32	0.13	−0.34	0.73	0
Cingulate	19.88	1.31 × 10 −5 ***	2.14	0.03	7
Insula	28.84	1.95 × 10 −7 ***	0.61	0.54	13
Cortical thickness
Frontal	92.32	3.77 × 10 −19 ***	0.96	0.34	36
Parietal	120.06	5.11 × 10 −24 ***	−0.03	0.97	38
Temporal	61.19	1.43 × 10 −13 ***	−0.42	0.67	25
Occipital	113.54	7.03 × 10 −23 ***	1.72	0.09	37
Cingulate	73.52	8.39 × 10 −16 ***	−2.44	0.02	25
Insula	27.31	3.94 × 10 −7 ***	0.92	0.36	12
Local gyrification index
Frontal	81.39	3.29 × 10 −17 ***	6.08	5.57 × 10 −9 ***	40
Parietal	84.05	1.99 × 10 −15 ***	7.32	5.17 × 10 −12 ***	42
Temporal	32.94	3.01 × 10 −8 ***	7.85	1.99 × 10 −13 ***	35
Occipital	17.85	3.50 × 10 −5 ***	6.19	3.04 × 10 −9 ***	22
Cingulate	19.50	1.57 × 10 −5 ***	4.85	2.42 × 10 −6 ***	18
Insula	32.05	4.51 × 10 −8 ***	8.10	4.12 × 10 −14 ***	36
Surface area
Frontal	0.59	0.44	9.18	3.70 × 10 −17 ***	28
Parietal	3.07	0.08	9.87	3.54 × 10 −19 ***	33
Temporal	5.97	0.14	10.32	1.72 × 10 −20 ***	34
Occipital	10.06	0.02	7.94	1.15 × 10 −13 ***	30
Cingulate	0.78	0.38	7.07	2.13 × 10 −11 ***	19
Insula	1.00	0.32	8.61	1.56 × 10 −15 ***	25

Results in bold were statistically significant

Statistics reported are from models including sex, scanner, and familiarity for each index. R² is for the full model. Statistics for LGI, IC, and CT models that also included SA as a covariate were negligibly different regarding age in each case. However, within the LGI model, the inclusion of SA was seen to eliminate all significant effects of sex. Similarly, in the IC model, the significant sex effect in the frontal region disappeared upon inclusion of SA. Adjusted significance level is p < 0.002. *p < 2 × 10⁻³, **p < 4 × 10⁻⁴, ***p < 4 × 10⁻⁵.