Summary: A new review explores how episodic memories are formed, stored and remodeled over time, revealing why our memories of past events often change. Rather than functioning as fixed files, memories consist of multiple components that can remain dormant until activated by environmental cues.
When retrieved, these components are combined with general knowledge, past experiences, and current context, creating updated versions of the original event. The findings help explain memory distortion and offer insights into mental health, learning, and legal settings where accuracy is important.
Key facts
Dynamic memories: Episodic memories are continually updated, not stored as perfect copies. Trigger-Based Recall: Hidden memory traces become conscious only when activated by cues. Real-world impact: Memory remodeling affects mental health, education, and legal decision-making.
Source: University of East Anglia
A study from the University of East Anglia is helping scientists better understand how our brains remember past events and how those memories can change over time.
A new paper published today explores episodic memory, the type of memory we use to remember personal experiences like a birthday party or a holiday.
The team says their work has important implications for mental health, education and legal settings where memory plays a key role.
Working in collaboration with the University of Texas at Dallas, the team demonstrates that memories are not simply stored as files on a computer.
Rather, they are made up of different parts. And while some are active and easy to remember, others remain hidden until something triggers them.
Importantly, the review shows that for something to count as a real memory, it must be linked to a real event from the past.
“But even then, the memory we remember might not be a perfect copy,” said lead researcher Professor Louis Renoult of the UEA Faculty of Psychology.
“It can include additional details from our general knowledge, past experiences, or even the situation we are in when we remember it.
“Memories of older events often go through a process called recoding, meaning the brain updates or reshapes the memory over time. This creates a chain of connections from the original experience to the version of the memory we can access now.
“This work helps us understand why our memories are not always reliable and how they can be influenced by time, context and even our own imagination.”
How the investigation occurred
The team examined nearly 200 psychology and neuroscience studies on memory representations, as well as philosophical articles and recent studies using animal models.
Professor Renoult said: “We wanted to suggest a new way of looking at things by combining ideas from different fields. The aim was to make sense of problems that have not yet been solved and generate new research.”
A key part of the study focused on how the brain physically stores memories, highlighting the role of the hippocampus, a part of the brain that helps form and organize memories.
The research explains how memory traces in the brain can remain latent and only become conscious representations when something (usually a signal from the environment) activates that memory trace.
“These conscious representations of our past are usually a combination of information recovered from the original experience, generic knowledge about the world and information relevant to the current situation,” Professor Renoult explained.
“While memories must have a causal link to past events to count as memories, they may differ each time they are retrieved.
“This means that memories can and do change. They could become less accurate or include new information, making them feel different from the original event.
A crucial part of our daily life.
“Understanding how memories are formed, stored and reshaped over time is crucial because memory underpins so much of our daily lives, from learning and mental health to decisions made in court.
“By revealing that memories are dynamic rather than fixed, this research helps us better understand why they can change and how that affects the way we think, feel and act,” he added.
Key questions answered:
A: Each retrieval combines traces of the original memory with generic knowledge and present context, transforming the memory into a revised version of the past.
A: It must be causally linked to an actual past event, although the remembered version may include altered or added details.
A: Understanding how memories evolve informs mental health treatment, supports better learning strategies, and highlights the limitations of eyewitness testimony.
Editorial notes:
This article was edited by a Neuroscience News editor. Magazine article reviewed in its entirety. Additional context added by our staff.
About this research news in memory and neuroscience
Author: Lisa Horton
Source: University of East Anglia
Contact: Lisa Horton – University of East Anglia
Image: Image is credited to Neuroscience News.
Original research: Open access.
“The cognitive neuroscience of memory representations” by Louis Renoult et al. Neuroscience and Biobehavior Reviews
Abstract
The cognitive neuroscience of memory representations.
This article considers the cognitive neuroscience of memory from a representational perspective with the aim of shedding light on current empirical and theoretical issues.
We focus on episodic memory, differentiating representations of active versus latent and cognitive versus neural memory. We adopt a causal perspective, according to which a memory representation must have a causal connection to a past event to count as a memory.
We note that, however, the retrieved episodic information may only partially determine the content of an active memory representation, which may comprise a combination of the retrieved information with semantic, schematic, and situational information.
We further observe that, especially in the case of memories of temporally remote events, recoding operations are likely to lead to a causal chain extending from the original experience of the event to its currently accessible memory trace.
We discuss how the reinstallation framework provides a mechanistic basis for the causal link between an experience, the memory trace that encodes it, and the episodic memory of the experience, highlighting the crucial role of hippocampal engrams in encoding neocortical activity patterns that, when active, constitute the neural representation of an episodic memory.
Finally, we analyze some of the ways in which a memory can be modified and, therefore, distanced from the episode that precipitated it.
