Regional neuroanatomical changes between morning and evening sessions. A, Multivariate regression demonstrates a mostly negative relationship between time of day and gray matter volume (FDR at q < 0.05; nonsignificant test statistics were set to zero for interpretability). B, Gray matter volume in the striate cortex and temporal occipital regions are heightened in the morning and reduced in the evening. Abbreviations: GMV, gray matter volume. For additional regions, see Extended Data Table 3-1 and for regional cortical thickness changes, see Extended Data Table 3-2.