Extended Data Fig. 9: Tight correlation between cerebral activity, physiology and skin brightness in sleeping chameleons.

a, Ten-minute sleep recording. From the top to the bottom, electromyogram (EMG); left and right electrooculogram (EOG); heart rate; breathing movement; beta power (10–40 Hz); local field potential (LFP) recorded in the dorsal ventricular ridge (DVR) represented in the frequency (color-coded map, from low (blue) to high power (yellow)) and the corresponding raw LFP signal (lower trace). b, Correlation between the beta power and skin brightness period (from different individuals represented by color-coded dots) relative to the temperature, showing that the cerebral and skin brightness infraslow rhythms are both temperature-dependent. c–i, The heart rate (c), beta power (d), muscle tone (e), left (f) and right (g) eye movement density, left (h) and right (i) eye opening relative to the breathing rate phase of the chameleon that was recorded with electrophysiology. The orange curve shows breathing rate relative to its own phase. The colored curve and shading show the mean and s.e.m. over all sleep bouts for this chameleon. j, The skin brightness, eye movement density and eye-opening relative to the breathing rate phase on the three chameleons where skin brightness was evaluated. The blue curve shows the breathing rate variations relative to its own phase. The colored curve and shading show the mean and s.e.m. over all trials and chameleons. On subfigures a–j, the gray arrows show the mean vector for each sleep bout. The color-coded arrows represent the average of all mean vectors. The vector length has been doubled for clarification. The p values were computed using a Rayleigh test, evaluating the uniformity of the sleep bout phase distribution. c–j, The number of individuals and replicates (sleep bouts) per species is indicated in Supplementary Table 1 (row ‘LFP/EEG’, ‘ECG’, ‘Breathing’, ‘EOG’, ‘EMG’). Phase-locking statistics were computed by testing the uniformity of the circular distribution using the Rayleigh test.