Rumination occurs when an individual becomes stuck and cannot navigate away from an unwanted thought. A high tendency to ruminate is linked to altered functioning of oscillations in the alpha (8-12Hz) and beta (13-30Hz) bands. Alpha and beta power dynamics are crucial for various cognitive functions, including episodic memory. Our study uses EEG recorded during a source memory task to assess how oscillatory dynamics in alpha and beta may change as a function of tendency to ruminate along with memory for contextual details (n=43). The source memory task instructs participants to remember an object and the side of the screen the object is presented on during study. During test, the previously studied objects are mixed with new objects and for each object the participant must make a recognition judgement of old left, old right, or new. Analysis of accuracy reveals that memory for contextual details is lessened for participants who have a high tendency to ruminate paired with higher anxiety. Reaction time did not appear to have a relationship with the predictor variables. During retrieval high ruminators exhibit less desynchronization in the beta band 250-1500ms post cue over right posterior parietal areas when successfully remembering just the object or remembering both the object and context. Alpha power shows less desynchronization 1000-1250ms post cue over parietal areas during retrieval when a high ruminator recalls the object and context, but there is greater desynchronization when they remember the object, but not the detail. Similar dynamics are observed during encoding for both oscillatory bands. The oscillatory differences between high and low ruminators suggest that high ruminators may encode a less detail rich memory trace and they may recruit more neural resources to focus retrieval when an attempt appears to be failing.
