At 12 months of age, the hippocampus is already able to codify memories: a difficult recovery would explain why we do not remember the first years of life.
Because we remember practically anything of our first three years of life – except for some sporadic episode that we believe we remember, but which often, unfortunately, is false? The origins of childhood amnesia are one of the most discussed and mysterious aspects of neuroscience.
Now a study in functional magnetic resonance imaging (FMRI) shows that The children’s brain is able to codify memories already at 12 months of age. And suggests that childhood amnesia is not a problem of “writing” of memories, but rather of theirs re -enactmentas already emerged in animal studies. The research was published on Science.
A coding problem? For a long time it has been assumed that the impossibility of reminding us specific events of the first years of life depended on a not yet complete development of the hippocampus, the brain structure that has a central role in the formation of new memories and which completes its training during adolescence. The problem is that verifying this and other theories about childhood amnesia is very complex.
Remember, but can’t say it? The peculiarity of the episodic memorythe ability to remember specific events located over time is in fact the possibility of describing those memories to others. A difficult process, when having to describe He is a child under 3 years of ageoften still in the pre-verbal phase.
For the new study, the researchers under the guidance of Nicholas B. Turk-Browne, neuroscientist of the Wu Tsai Institute at the University of Yale (Connecticut, USA), used a particular approach that allowed to understand if children from 4 to 24 months of life they had memorized An image seen just before.
This is not new to me … The little ones were able to observe images never seen before a face, a scene or an object. After being subjected to other images “in the middle”, they were put in front of the unpublished photos seen previously and to others completely new. The children focused longer to observe the images they had already met – as if in fact were familiar.
Active hippocampus. In the meantime, scientists have subjected them to a type of functional magnetic resonance imaging (FMRI) that can be performed on firm and moving children, and who showed the activity of their hippocampus.
The greater the activity in the hippocampus when a child or newborn looked at a new image, the longer that same image was observed when he reappeared the second time.
So the hippocampus was codifying new memories, with a particularly intense activity in the rear of the hippocampuswhat in adults is associated with episodic memory.
The ABC of reality. What was observed earned for all 26 children, but in particular for those with more than 12 months (half of the sample). The idea is that The hippocampus develops to support learning functions. Past studies had hypothesized that before the year and already 3 months of life, children learn with a form of learning non -episodic but statisticalwhich extracts recurring patterns from situations to try to grasp the general rule.
This type of memory is associated with the front of the hippocampus, involves a different neural path and precedes the episodic onewhich could develop from the year of life. The two forms of learning reflect different needs of the child: “Statistical learning concerns the extraction of the structure in the world that surrounds us, fundamental for the development of language, vision, concepts” explains Turk-Browne.
Impossible recovery. But if the memories are already codified in the hippocampus already at 12 months of age, Where do they end up, then? Two hypotheses: the first is that the coded tracks are not converted into long -term memories. The second, is that the memories of early childhood there are, but that they are not accessible. The second theory is more accredited, even more so after the discovery that the hippocampus already knows how to codify memories to one year of life. The same group of scientists is already working to understand if these traces are still present in preschool children, and then vanish with growth.
