In a groundbreaking study, researchers have understood that the human brain replays past events to make sense of the present occurrence.

This phenomenon extends beyond spatial experiences and occurs during non-spatial experiences as well. It provides insights into how our brains create narratives and helps us make sense of the world.

The findings, published in Nature Neuroscience, indicated the process mirrors the mental replay observed in rodents to understand their spatial environment.

Researchers at the University College and the Queen Mary University in London delved into the idea that the human brain engages in the replay of past events, even in non-spatial contexts, and found the reactivation process of past events in the human brain appears to be more intricate than what is observed in rodents.

"We know that the brain can 'replay' information that was encountered in the past, although this has mainly been studied in navigation tasks involving rodents," Avital Hahamy, one of the researchers who carried out the study, told Medical Xpress. "We also know that the human brain chunks our ongoing experience into smaller events that we can later recall as a narrative of our daily experience (e.g., your morning events might include taking the tube to work, reaching the office, going into a meeting, etc.).

"We wondered whether the human brain also replays past information to connect these different events into an overarching understanding of our experiences (e.g., allowing us to understand why a meeting started without us by linking this present event to a past event, such as the tube running late)."

The researchers asked participants to watch a movie or listen to narrated stories, while their brain activity was recorded using an fMRI scanner considering they invoke real-world experiences. The study found the human brain replays past events during engagement with narratives. This replay process aids in comprehending ongoing experiences. Unlike rodents, this replay occurs while events are unfolding rather than during periods of rest.

"We found that the same brain regions that replay spatial information in the rodent brain also replay narrative events in the human brain," Hahamy said. "In other words, replay, previously thought to mainly support spatial navigation, could also underlie the human ability to make sense of narratives. Moreover, while research in rodents proposed that replay is used to store past events into memory, mostly when rodents rest or sleep, we suggest it can also be used to make sense of the present, on the fly, while events are unfolding."