Summary: A new study has uncovered the neural mechanisms behind how we process and memorize everyday events.
A new study by a University of Washington researcher offers new insights into how the brain takes longer to process and remember everyday events.
Zacharias Regh, assistant professor of psychology and brain sciences at Washington University of Arts and Sciences in St. Louis, and co-author Charan Ranganath of the University of California, Davis, used functional MRI scanners to monitor the brains of subjects watching short videos of scenes that could have come from real life. These included men and women working on laptops in a cafe or shopping at a grocery store.
“They were very common scenes,” Reg said. “No car chases or anything.”
Research subjects then immediately described the scenes in as much detail as they could. The mundane snippets led to intriguing findings, including that different parts of the brain work together to understand and remember a situation.
Networks in the frontal lobes of the temporal lobe, a region of the brain long known to play an important role in memory, focus on subjects regardless of their surroundings. But the posterior medial network, which involves the parietal lobe at the back of the brain, focuses more on the environment. These networks then send information to the hippocampus, Regg explains, which combines the signals to form a coherent picture.
Researchers have previously used very simple objects and scenarios – such as a picture of an apple on a beach – to study the different building blocks of memory. But life is not that simple, he says. “I was wondering if anyone had done this kind of research with dynamic real-word situations and, shockingly, the answer was no.”
New research suggests that the brain creates mental sketches of people that can be moved from one location to another, much like an animator might copy and paste a character into different scenes. “It may not seem intuitive that your brain can create a sketch of a family member as it moves from place to place, but it’s very efficient,” he said.
Some subjects may recall scenes from cafes and grocery stores more completely and accurately than others. Reg and Ranganath found that those with vivid memories used the same neural patterns when recalling scenes that they used when watching the clips.
“The more you can bring these patterns back online when describing an event, the better your overall memory will be,” he said.
At this point, Reg said, it’s not clear why some people seem more adept than others at reproducing the thought patterns needed to access memory. But it’s clear that many things can get in the way. “A lot of things can go wrong when you’re trying to retrieve a memory,” he said.
Even memories that seem crisp and vivid may not actually reflect reality. “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.
Rigg is one of the University of Washington faculty members involved in the research cluster “The Storytelling Lab: Bridging Science, Technology and Creativity,” part of the Incubator for Transdisciplinary Futures. Led by Jeff Jacques, Chair of the Department of Psychological and Brain Sciences, along with Ian Bogost and Colin Barnett, the Storytelling Lab explores the psychology and neuroscience of narrative.
In the future, Reg plans to study the brain activity and memory of people watching more complex stories.
“The Storytelling Lab fits perfectly with the scientific questions I find most exciting,” says Reg. “I want to understand how the brain creates and remembers narratives.”
Dr. with the news of this memory research
Author: Chris Woolston
Contact: Chris Woolston – WUSTL
Image: Image is in public domain
Original Research: Access to all.
“Flexible reuse of cortico-hippocampal representations during encoding and recall of natural events“By Zachariah M. Reg et al. Nature communication
Flexible reuse of cortico-hippocampal representations during encoding and recall of natural events
Although each life event is unique, there are considerable similarities between the events. However, little is known about whether or how the brain flexibly represents information about different event elements during encoding and remembering.
Here, we show that different cortico-hippocampal networks systematically represent specific elements of events depicted in videos, both during online experience and during episodic memory retrieval.
Regions in an anterior temporal network represent information about people, generalizing across contexts, whereas regions in a posterior medial network represent context information, generalizing across people.
The medial prefrontal cortex generalized across videos depicting the same event schema, whereas the hippocampus maintained event-specific representations. Similar effects were observed in real-time and at recall, suggesting reuse of event elements in overlapping episodic memory.
Together these representational profiles provide a computationally optimal strategy for folding memory for different high-level event elements, allowing efficient reuse for event comprehension, recollection, and imagination.