Figure 4.

(a), (c) Estimated leading subject level first-stage eigenfunctions, $\{{\varphi }_k^{(1)}(t|s)\},k=1,2$, respectively, for the TD group. (b), (d) Estimated leading subject level second-secondstage eigenfunctions $\{{\psi }_{kk\prime }^{(1)}(s)\},k,k\prime =1,2$.