As we go about our lives, we experience a continuous stream of information. Yet when thinking about the past, we remember it as discrete events – ‘I attended a meeting’; ‘I went to see a movie’. How is our continuous experience transformed into these separate memories? Research has shown that people naturally segment experience into events, with relatively high agreement between them as to when transitions between events (event boundaries) occur. The current project is aimed at revealing how event boundaries affect the memory systems in our brain in charge of encoding new memories. An intriguing hypothesis, which we set out to test, is that event boundaries trigger activity in brain regions in charge of memory encoding. We found that event boundaries indeed trigger a strong response in the hippocampus, a key region involved in encoding of new episodes, and that the response was stronger for more salient boundaries. Moreover, the hippocampus responded primarily during these boundaries, and relatively little at other points in time. Together, this suggests that during continuous experience, event boundaries may trigger encoding activity that wraps up the preceding event as a cohesive unit, separating it from the next event. This project is part of a global objective to understand how we form memories for entire events. Memory research has traditionally focused on how the brain encodes memories for simple items, such as words, or pictures. By expanding our knowledge to uncover how the brain encodes whole episodes, which are much more similar to our real-life experience, we are laying the foundations for a better understanding of memory disorders.
