Fig. 1: Low-dimensional population activity in midbrain and pons during sleep.
From: Low-dimensional population dynamics in the brainstem gate REM sleep
a, Schematic illustrating Neuropixels recording in pons and midbrain areas of a C57BL/6J mouse. b, Example recording session, including hypnogram, normalized EEG spectrogram, EMG amplitude and heat map representing the firing rates of 185 simultaneously recorded neurons. Each row color-codes the z-scored firing rate of a single unit. Neurons are sorted by brain region and depth. The color bar on the right indicates the brain regions. FR, firing rate; PSD, power spectral density. c, Anatomical reconstruction of electrode tracts within the 3D Allen Mouse Brain Reference Atlas from six animals. d, Coronal brain schematic depicting recorded brain areas and number of neurons per area. e, Percentage of the shared variance in the population activity captured by increasing numbers of PCs. Gray dots indicate the mean across mice; error bars denote 95% confidence intervals (CIs); black dots represent individual mice (n = 6). f, Hypnogram, normalized EEG σ power (Methods), EMG amplitude and PC1/PC2 (both PCs are plotted using the same scaling). g, Mean absolute amplitude of PC1 to PC22 during REM sleep. Repeated-measures (RM) analysis of variance (ANOVA), P = 2.79 × 10−60, F(21,105) = 102.90; two-sided paired t-tests comparing PC1 with PC2, …, PC22, P < 0.0043; n = 6 mice. Dots indicate individual mice; error bars denote 95% CIs. See Supplementary Table 1 for statistical details. h, Normalized cross-correlation between PC2 and EEG σ power during NREM sleep (Methods). Black line indicates the mean across mice; gray lines denote individual mice. Two-sided one-sample t-test, P = 7.42 × 10−7, T(5) = 30.24; n = 6 mice. i, Power at ISO peak frequency for PC1 to PC22. For each animal, we calculated the peak ISO frequency in the EEG σ power (fiso, Extended Data Fig. 1e) and then determined for each PC its power at fiso. RM ANOVA, P = 2.19 × 10−37, F(21,105) = 33.90; two-sided paired t-tests with Bonferroni correction comparing PC2 with PC1, PC3, …, PC22, P < 0.041; n = 6 mice. Error bars indicate 95% CIs. See Supplementary Table 1 for statistical details. a.u., arbitrary units.
