The present study aimed to find whether pre-sleep arousal caused by rumination gave rise to increased prefrontal cortical activity during subsequent sleep, and if this activity varied depending on pre-sleep rumination scores . Also, it aimed to see if post-sleep rumination is lower than pre-sleep rumination and if pre-sleep rumination lasts into subsequent wakefulness. It is not clearly understood that increased arousal lasts into subsequent sleep and whether post-sleep rumination is related to either pre-sleep rumination or prefrontal arousal during sleep. Targeting pre-sleep arousal may help alleviate sleep difficulty linked to rumination and subsequent post sleep rumination. 10 participants slept in a sleep laboratory for a two-hour daytime nap captured between 10:30am – 14:30pm, monitored with polysomnography (PSG) and fNIRS. PSG was used to measure sleep parameters and fNIRS monitored prefrontal activation during sleep. Rumination was elicited with two induction tasks pre- and post-sleep with state rumination measures pre- and post-induction. This provided a measure of induced rumination effectiveness. State rumination scores did not significantly differ, although increases were noted between both pre- and post-induction state rumination scores. Total haemoglobin was lowest in REM and highest during N3 . No significant main effect of pre-sleep rumination was found. A significant interaction effect of pre-sleep rumination scores on SWA and HbO during N3 was indicated. This may be indicative of ruminative thinking as a result of the pre-sleep induction. Overall, there was no profound effect of pre-sleep rumination on varying levels of neural activity across sleep stages in both cortical and EEG activity.
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