Predictive performance of the SCN-based brain age estimator as a function of ICA orders. The predictive performance of the brain age estimator increased with ICA order size; MAE ranged from 4.92 to 3.74 and R² from 0.49 to 0.69. Increasing predictive performance inflected at 40 ICs (MAE = 3.97 years, R² = 0.66). Red/blue shading: ±1 standard error. Abbreviations: MAE, mean absolute error; and R², coefficient of determination.