FIG 2.

The role of LC (locus coeruleus) in global cognition and apathy. The MoCA (Montreal Cognitive Assessment) and Apathy Score (AS [Apathy Scale]) in PD and PSP (progressive supranuclear palsy) correlate with LC contrast. The spatial distributions within the LC contributing to global cognition and apathy are revealed from voxelwise regression models in 3D rendering and multiplanar views (MoCA: A and B, AS: D and E, threshold free cluster enhancement, 10,000 permutations, FWE [family‐wise error]‐corrected P < 0.05; age and LEDD [levodopa equivalent daily dose] were included as covariates of no interest). The linear relationships between atlas‐based LC CNR (contrast‐to‐noise ratio) and clinical scores over both disease groups were tested using mixed‐effect models, with individual variation illustrated by scatter plots for (C) MoCA and (F) AS, respectively (for visualization, fitted lines and confidence intervals were provided using linear regression models; see “Results” section for statistical tests using mixed‐effect linear models). [Color figure can be viewed at wileyonlinelibrary.com]