Raw and spectral characteristics of forebrain EEG during activated and deactivated states were similar across during natural sleep and urethane anaesthesia.
A) Expanded neocortical and hippocampal EEG traces across natural sleep and urethane anaesthesia in the same animal showing examples of activated and deactivated patterns in both situations. Regardless of condition, activated and deactivated patterns were highly similar. B) Spectra of cortical and hippocampal EEG traces overlaid across conditions for the same electrographic patterns. Although the peak frequency of hippocampal theta power during REM was at a higher frequency (∼7 Hz) than during the activated state under urethane anaesthesia (∼4 Hz), all other spectra across conditions appear highly similar. Scatter plot of C) peak frequencies and D) power (right panel) for neocortical and hippocampal signals during the activated and deactivated state for each animal. Except for the peak frequency of hippocampal signals during activated patterns, there were no significant differences across natural sleep and urethane anaesthesia.