Poster D40, Monday, March 27, 8:00 – 10:00 am, Pacific Concourse
Dynamics of hippocampal-prefrontal cortex interactions supporting event segmentation
Anna Jafarpour1, Sandon Griffin1, Jack J. Lin2, Robert T. Knight1; 1University of California, Berkeley, California, 2University of California, Irvine, California
Event-segmentation is a process applied to the stream of perception that identifies the temporal-context of an episode. The stream of events is segmented based on their temporal relevance that starts with perception of a salient change. The intensity of changes in the stream of perception depends on the level of the new event saliency or novelty. The human prefrontal (PFC) and the medial temporal cortices (MTL) are critical for detecting salient events and establishing their temporal-context. We recorded intracranial-electroencephalography from the PFC and MTL of epilepsy patients (n=6) with electrodes implanted for clinical purposes. The patients watched movies and the degree of event saliency for every movie frame was established by an independent behavioral analysis. We used this behavioral regressor to examine the relationship between event saliency and neural activities. The results revealed that the power of low gamma band activity (30-70Hz) and high-gamma band (70-150Hz) activity in the hippocampus, PFC and OFC predicted the intensity of event saliency (corrected P<0.05). Moreover, the functional connectivity between the medial PFC and the MTL in the theta band changed according to the saliency of events. Our findings provide evidence for the dynamics of PFC-MTL interactions coordinating event segmentation in the stream of perception.
Topic Area: EXECUTIVE PROCESSES: Goal maintenance & switching