Fig. 1

a point densities of 2D state space plots of an “average” animal with distinct clusters at the parietal lobe across 4 selected days. Each plot shows 6 h of EEG activity, and each point represents 1 s of EEG activity after application of a 20 s wide Hanning window. Warm colors indicate regions where the average density is high and cool colors indicate low average density. The numbers in the color bar are arbitrary. b “Average” state space densities at the 4 selected days, projected into ratio 2. Each of the vigilance state space point densities (not shown) was projected separately into ratio 2. Blue wake, green REM, Red NREM and Black summation of all vigilance sleep states. Note that the peak of the Wake vigilance state is located at lower ratio 2 than the peak of NREM