Table 4.

Results from regression analyses with TBV-corrected volumes

	Regression with age				Regression with age and age2
	β	F	p	R2	F	p	R2	p age2a
Cortex volume	−0.83	384.98	1.98E-45	0.70	276.27	7.64E-54	0.77	1.94E-11
Cerebral WM	0.82	356.03	1.87E-43	0.68	230.68	6.59E-49	0.73	2.15E-8
Hippocampus	0.24	9.85	0.002	0.06	7.62	6.81E-4	0.08	0.025
Amygdala	0.34	21.64	6.62E-6	0.11	14.18	2.05E-6	0.14	0.015
Caudate	−0.20	6.74	0.010	0.04	4.26	0.016	0.05	0.188
Putamen	−0.41	34.55	2.16E-8	0.17	17.23	1.56E-7	0.17	0.754
Pallidum	−0.33	20.03	1.40E-5	0.11	10.00	7.87E-5	0.11	0.773
Accumbens	−0.31	17.44	4.75E-5	0.09	10.20	6.60E-5	0.11	0.097
Thalamus	0.10	1.83	0.177	0.01	0.91	0.403	0.01	0.963
Cerebellum GM	−0.27	13.03	4.04E-4	0.07	7.73	0.001	0.08	0.13
Cerebellum WM	0.45	41.66	1.10E-9	0.20	29.86	8.03E-12	0.26	1.79E-4
Brainstem	0.55	72.68	8.21E-15	0.30	45.43	1.70E-16	0.35	4.09E-4
Lateral ventricle	0.38	28.09	3.58E-7	0.14	14.42	1.67E-6	0.15	0.379
Inferior lateral ventricle	−0.07	0.82	0.367	0.01	0.410	0.664	0.01	0.936
Third ventricle	0.14	3.31	0.071	0.02	3.33	0.038	0.04	0.070
Fourth ventricle	0.02	0.07	0.796	3.96E-4	0.07	0.934	0.001	0.793

Results shown are from two separate regression analyses with TBV-corrected volumes, one with only age as the predictor variable and the other with both age and age² as predictor variables. Bold characters for R² indicate a statistically significant quadratic age relationship.

^aThe p value for the unique contribution of age² to the explained variance in brain volume.