Figure 2

Representative cartoon of the angular distances between vectors representing resting state network (RSN) functional connectivity (FC) in different sleep–wake stages. Vectors exist in multidimensional space, with the number of dimensions dependent on the number of FC edges that are in a given category (e.g., each vector exists in 91-dimensional space for the category “ALL edges”). However, only two dimensions are represented here, for illustrative purposes. Indicated angles are the degree-equivalent of the angular distances between the mean vectors for each stage (indicated as colored arrows), with the mean wakefulness vector always used as the reference point. Angles between sleep stages are not indicated, however, the statistical significance of these differences is indicated by asterisks (single/double/triple asterisks indicate p < 0.05/0.01/0.001, respectively). Note that angles between any pair of vectors actually exist in separate dimensional planes and are only represented in the same plane for illustrative purposes. Also note that angle equivalents between sleep stages are not equal to differences in the individual angles relative to wake, as such angles exist in multidimensional space and must be calculated separately. Colored triangles indicate the spread of vectors for each stage, again for illustrative purposes, as they are actually spread across multidimensional space. (A) ALL edges (N = 91 dimensions). (B) ALL HIGHER-ORDER resting state network edges (N = 70). (C) Default mode network (DMN) & Fronto-Parietal network (F-P) edges (N = 46). REM rapid eye movement, NREM2 non-REM stage 2, SWS slow wave sleep.