Why does the brain record our memories in chronological order?

The brain remembers our memories in chronological order thanks to "temporal cells".Neuroscientists try to unravel in more detail the functioning of these neurons, located in the hippocampus.

If you remember your lunch, you will remember having ate the dessert after the main dish.You can even remember the details in the course of the meal - a phone call interrupted you when you cut a tomato, for example.The same goes for your vacation, for your last meeting at work, and so many other moments registered in your memory.It's episodic memory.She is chronological.Memories are recorded and remembered, most of the time, in the order in which they really came.This seems completely obvious.But how to explain it?Where does this so basic notion of time come from?

It was this question that a research group in neuroscience attacked.The results were published on June 28, 2021 in Jneurosci and they involve the existence of "temporal cells" in our brain.

The time flow is recorded by eras

"An essential characteristic of episodic memory is our ability to temporally bring together different elements of an experience in a coherent memory.The ‘temporal cells’ of the hippocampus - neurons that represent temporal information - could play an essential role in this process, "explains the research paper.These cells should be perceived as a kind of glue or sewing thread, structuring our experience in the form of a chronologically coherent memory.Their presence has already been demonstrated in rodents, such as rats, but an in -depth study is more complicated in human beings.

Why are our memories in chronological order in our memory?

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To decipher this mechanism, neuroscientists behind this study rested on microelectrodes located in the hippocampus of 15 epileptic patients.These devices are used to monitor the electrical activity of the brain.If it has been called upon epileptic patients, it is because the electrodes was already present to monitor the origin of epilepsy seizures;There was therefore no need to carry out an invasive operation specifically dedicated to the progress of this research.

As part of the experimentation, patients were faced with series of images, which they had to memorize in order.Then, the images were presented again, and patients were asked to predict certain images in a suite that had already been shown.The electrodes then made it possible to see that the "temporal cells" located in the hippocampus were triggered during the presentation of the images "at successive moments", but also during the breaks between the images, and during the moments when it was asked toMake predictions of already shown images.

These results therefore suggest that within the hippocampus is a brain activity in the form of "time flow" allowing to cut the memories of distinct "eras".It is an internal process, which takes place outside of external stimuli, as it takes place even for break periods.Neuroscientists behind the study describe this as a kind of mental time travel: temporal cells are internal terminals that assemble the "what" and the "where" with a "when".

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