Summary: A new study reveals how the brain organizes and reuses neural representations to perceive and remember everyday events.
Source: WUSTL
A new study from Washington University provides fresh, detailed insight into how the human brain encodes and later recalls ordinary, real-world events.
Zachariah Reagh, an assistant professor of psychological and brain sciences at Washington University in St. Louis, together with co-author Charan Ranganath of the University of California, Davis, used functional MRI to track brain activity while volunteers watched short, realistic video clips. The scenes were deliberately ordinary—people working on laptops in a café or shopping in a grocery store—so researchers could study how the brain handles everyday experience rather than dramatic, cinematic moments.
“They were very ordinary scenes,” Reagh said. “No car chases or anything.”
Immediately after viewing each clip, participants described what they had seen in as much detail as they could. Those descriptions, paired with the brain imaging data, revealed a coordinated system in which distinct brain networks emphasize different elements of an event and then converge on the hippocampus to form a unified memory.
Specifically, activity in anterior temporal networks—regions toward the front of the temporal lobe—encoded information about people in the scenes regardless of the surrounding context. In contrast, the posterior medial network, which spans areas near the back of the brain including the parietal lobe, concentrated on environmental and contextual details. Both streams of information were relayed to the hippocampus, which integrated them into a coherent event representation.
Previous laboratory research often relied on simplified stimuli—an isolated object against an unrelated backdrop—to parse the building blocks of memory. Reagh noted that such simplified designs leave open the question of how those components operate during dynamic, naturalistic experiences. “I wondered if anyone had done these types of studies with dynamic real-world situations and, shockingly, the answer was no,” he said.
The new findings suggest that the brain forms flexible, transferable sketches of people and contexts. In other words, the neural pattern that represents a person can be reused across different locations in memory, much like an animator reuses a character across multiple scenes. This efficient reuse of component representations supports rapid understanding and flexible recall of overlapping events.
Not all participants remembered the clips equally well. Reagh and Ranganath found that those who produced the most accurate and detailed descriptions tended to reinstate the same neural patterns during recall that had been present while watching the videos. In short, stronger overlap between encoding and retrieval patterns correlated with clearer, more complete memories.
“The more you can bring those patterns back online while describing an event, the better your overall memory,” Reagh explained. Why some people are better at reinstating these patterns is still unclear. He cautions that many factors can interfere with retrieval: attention, interference from other memories, and the complexity of the event itself can all disrupt the process.
Reagh also emphasizes a broader point about the nature of memory. Even vivid memories are not perfect recordings. “I tell my students that your memory is not a video camera. It doesn’t give you a perfect representation of what happened. Your brain is telling you a story,” he said, underscoring that recollection involves reconstruction as well as retrieval.
This research is part of a larger effort at Washington University called the Storytelling Lab: Bridging Science, Technology, and Creativity, which is housed in the Incubator for Transdisciplinary Futures. Led by Jeff Zacks with collaborators Ian Bogost and Colin Burnett, the lab explores how narrative structure and brain processes interact—an ideal environment for Reagh’s interest in how the brain builds and remembers narratives.
Looking ahead, Reagh plans to extend this work to more complex narratives and longer, multi-stage stories to see how cortico-hippocampal systems support comprehension and recall when events overlap or evolve over time. Such follow-up studies aim to bridge laboratory findings with the messy realities of everyday life.
About this memory research news
Author: Chris Woolston
Source: WUSTL
Contact: Chris Woolston – WUSTL
Image: The image is in the public domain
Original Research: Open access. “Flexible reuse of cortico-hippocampal representations during encoding and recall of naturalistic events” by Zachariah M. Reagh et al., published in Nature Communications.
Abstract
Flexible reuse of cortico-hippocampal representations during encoding and recall of naturalistic events
Although every life event is unique, events share substantial commonalities. This study examines whether and how the brain represents different components of events—such as people, context, and schemas—both while experiencing them and later during episodic recall.
The results show that distinct cortico-hippocampal networks systematically represent specific event components in videos, during both online experience and memory retrieval. Regions in an anterior temporal network encoded person-specific information that generalized across contexts, while regions in the posterior medial network encoded contextual information that generalized across people.
Medial prefrontal cortex generalized across different videos that shared the same event schema, whereas the hippocampus preserved event-specific representations. Comparable patterns appeared both during viewing and during recall, indicating the flexible reuse of component representations across overlapping episodic memories.
Together, these representational profiles suggest a computationally efficient strategy: different brain networks specialize in distinct high-level event components, enabling flexible reuse for comprehension, recollection, and imagination of everyday experiences.