Progressive changes in cortical state before and after spontaneous arousals from sleep in elderly and middle-aged women

▶Cortical state exhibits systematic changes before and after a spontaneous arousal. ▶Cortical state is still altered after the end of a scored arousal. ▶Bursts of 0.2-2.0 Hz power pre-arousal lead to shorter arousals in middle-aged subjects only. ▶The effect of arousing stimuli may be modulated by the <1 Hz cortical oscillation.