Figure 3
From: The sleep EEG envelope is a novel, neuronal firing-based human biomarker
An illustration of EEG envelopes, the colliding window method and its results. (A) Illustrates the colliding window method. (B) Shows a single epoch of illustrative envelope and MUA data (ECoG low delta envelope and smoothed MUA from the fifth IME channel located in cortical layer III). The Pearson correlation of the two signals is shown for reference. Both the ECoG envelope and the MUA is detrended and demeaned, but not z-transformed. (C) Shows the distribution of available sleep data after artifact rejection using the colliding window method. For each participant, black lines mark the data segments used in analysis. The lower panel shows the total number of participants with available data as a function of time after recording start. Note the lack of systematic undersampling of any part of the night. (D) Illustrates the log-transformed envelope spectra. All data was z-transformed by frequency band to eliminate mean differences. The frequency axis is shown on a log scale to enhance the low frequency ranges which are of particular interest. Note spectral peaks at ~ 0.05–0.06 Hz, ~ 0.25 Hz and ~ 1 Hz, the latter most prominent in the beta range.
