A study shows that when remembering something from our past, the entire event can be reactivated in the brain, including incidental information, such as what music may have been playing. “When we recall a previous life event, we have the ability to re-immerse ourselves in the experience,” said Dr. Aidan Horner of UCL.
“We remember the room we were in, the music that was playing, the person we were talking to, and what they were saying. When we first experience the event, all these distinct aspects are represented in different regions of the brain, yet we are still able to remember them all later on. It is the hippocampus that is critical to this process, associating all these different aspects so that the entire event can be retrieved.”
The researchers showed that associations formed between the different aspects of an event allow one aspect to retrieve all the other aspects, a process known as pattern completion. For example, when remembering who we saw, we often remember other details, such as what they were holding and where they were. This means that the entire event can be re-experienced in full, the researchers say.
Using fMRI, the researchers discovered that different aspects of an imagined event are reflected in activity in different regions of the brain. When asked about one aspect of an event, activity in the hippocampus correlates with reactivation in these regions, including those incidental to the task, and that this reactivation corresponds to the full event coming to mind.
“This work supports a long-standing computational model of how memory might work, in which the hippocampus enables different types of information to be bound together so that they can be imagined as a coherent event when we want to remember what happened,” added senior author Professor Neil Burgess.