highly significantp < .001
As expected in the MoBaNeuroCog sample, all total brain measures and WM, were significantly non-linearly related to age, as indicated by estimated degrees of freedom (edf) substantially greater than 1 and highly significant smooth terms (area: edf=5.52, F=143.1, p < .001; volume: edf=7.17, F=78.7, p < .001; thickness: edf=5.23, F=62.0, p < .001; WM: edf =4.74, F=213.4, p < .001).