Representational dynamics of memories for real-life events

The continuous flow of experience that characterizes real-life events is not re-corded as such in episodic memory but is condensed as a succession of event seg-ments separated by temporal discontinuities. To unravel the neural basis of this representational structure, we recorded real-life events using wearable camera technology and used fMRI to investigate brain activity during their temporal un-folding in memory. We found that, compared to the representation of static scenes in memory, dynamically unfolding memory representations were associ-ated with greater activation of the posterior medial episodic network. Strikingly, by analyzing the autocorrelation of brain activity patterns at successive time points throughout the retrieval period, we found that this network showed higher temporal dynamics when recalling events that included a higher density of event segments. These results reveal the key role of the posterior medial network in representing the dynamic unfolding of the event segments that consti-tute real-world memories.