Fig. 4: Low dimensional dynamic signature across brain states.
From: Sleep fMRI with simultaneous electrophysiology at 9.4 T in male mice
a Spatial maps for the first four principal components (PCs) of BOLD signals. b Major brain divisions on 3D surface viewing as in (a). Abbreviations of ROI names were listed in Supplementary Data 1. c Circular distribution of temporal weights of PCs (tPCs) from the start to the end of each brain state: AW (left, n = 2703 epochs), NREM (middle, n = 2498 epochs) and REM (right, n = 165 epochs). Epochs with short durations (<60 s) were excluded and further applied to the following analysis. Radius of radar plots, tPCs; Color line, mean tPCs; gray shadow, the 95% confidence interval (CI) of null control (1000 shuffling). d Transition probability of brain states. e Averaged electrophysiological power spectrogram (upper panel) and mean (+/− SEM) tPCs of BOLD signals (lower panel) relative to brain state transitions (“AW to NREM”, n = 1803 epochs; “NREM to AW”, n = 1720 epochs; “NREM to REM”, n = 140 epochs; “REM to AW”, n = 128 epochs). Gray shadow, the 95% CI of null control. f Low dimensional manifold of BOLD signals traversed by the brain state across first three PCs, with arrows depicting the directions of flow along the manifold. g Similar to (f) but in two-dimensional electrophysiological space. Color dots, states per second. h Asymmetric trajectories of brain state transitions between AW and NREM states. Large distance of low dimensional manifolds in electrophysiological (f) and BOLD (g) spaces between “AW to NREM” and reversed “NREM to AW” transitions. Statistical significance was calculated by one-tailed t-test. Colored shadow, SEM. a.u. arbitrary unit. Source data are provided as a Source Data file.
