Trinity study finds way to bring back early childhood memories

13 Nov 2023

Image: © Jonathan/

Published in Science Advances, the study led by Dr Sarah Power shows how memories of early life are affected by forms of autism.

Scientists at Trinity College Dublin (TCD) have found that infantile amnesia, or forgetting memories from early childhood, is both preventable and reversible.

While it is common for humans to forget memories that formed before they were two years of age, the team based in TCD investigated how infantile amnesia is affected by forms of autism.

“Infantile amnesia is possibly the most ubiquitous yet underappreciated form of memory loss in humans and mammals,” explained Dr Tomás Ryan of TCD, who is a senior author of an article based on the study published in Science Advances last week.

“Despite its widespread relevance, little is known about the biological conditions underpinning this amnesia and its effect on the engram cells that encode each memory. As a society, we assume infant forgetting is an unavoidable fact of life, so we pay little attention to it.”

Autism in both humans and mice is known to be caused partly by the maternal immune response, which is triggered in response to infection during pregnancy. Ryan and the team found for the first time that this altered brain state also prevents the usual loss of memories formed during infancy.

Using a mouse model, their study showed that exposure to maternal immune activation, where inflammation is artificially induced during pregnancy in the absence of infection to alter a child’s brain development, acts as a safeguard against developmental memory loss in early life.

This is done by impacting the way specialist memory cells called engrams in the brain function.

“These new findings suggest that immune activation during pregnancy results in an altered brain state that alters our innate, yet reversible ‘forgetting switches’ that determine whether the forgetting of infant memories will occur,” Ryan explained.

“This research holds significant implications for enhancing our comprehension of memory and forgetting across child development, as well as overall cognitive flexibility in the context of autism.”

Dr Sarah Power, lead author of the study and a postdoctoral researcher at the Max Planck Institute for Human Development in Berlin, said that our brain’s “early developmental trajectories” seem to affect what we remember or forget as we move through infancy.

“We now hope to investigate in more detail how development affects the storage and retrieval of early childhood memories, which could have a number of important knock-on impacts from both an educational and a medical perspective.”

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Vish Gain is a journalist with Silicon Republic