Science

What happens with our first memories?

Do you remember where you were when you said your first word? And what was the season when you took your first step? … You don’t remember, do you? Don’t panic, that’s perfectly normal!

The reason why we cannot remember the first years of life is a mystery that has intrigued scientists for more than a century.
This is indeed a very interesting topic: we can try as hard as we want, but our first memory will never be linked to the very first years of our life, between 0 and 3 years or so.

Why? Did we erase everything? Were we too small and our brain too immature to remember?

What happens with our first memories?

It’s a question that has caught the attention of the scientific community since the late 1800s but we had to wait for Freud to come up with the definition we know today: “infantile amnesia”.

Let’s try to understand this better…

ARE MEMORIES FORMED?

This doubt arose from the consideration that in the first years of life the language, the sense of self, and also the ability to differentiate oneself from others (for example, if I do not like broccoli it doesn’t mean that everyone does not like broccoli), is not complete and defined.


But an important turning point came in the mid of 1900s when they discovered that this phenomenon not only occurs in human beings but also in animals, especially in mice and rats, thanks to the experiment carried out in the Byron Campbell laboratory, Princeton, in the United States. Campbell put a young mouse in a special room, different from the one he normally lived in, and in that room presented him with a sensory stimulus. The next day he observed that, when the mouse was put back in that room, he exhibited the same reaction of the day before, but he had no reaction if he was put back in the same room after a longer time. This proves that the memory linked to the first experience was formed because the next day the mouse remembered and reacted, but this memory seemed to be lost after a while.

WHICH PART OF THE BRAIN IS RESPONSIBLE FOR MEMORIES?

Around the 1950s a patient named Henry Molaison suffered from severe epileptic crises; because of these crises, a brain area called the medial temporal lobe was removed.
These are two symmetrical areas that lie between the temples, the ears and the adjacent to the ears. It is the area where the hippocampus is located, among others, a structure that is important for the formation of memory and for spatial orientation.  Following the removal of this area, this patient could no longer form long-term memories. However, Molaison had not lost the ability to memorize new skills, as happens to children: walking, talking, eating, because learning these skills and memories of everyday life are processed from different areas of the brain.
The case of Henry Molaison revolutionized the knowledge of memory organization and made a decisive contribution to future scientific research.

Medial Temporal Lobe for post blog
A section of the temporal lobe with the entorhinal cortex (above) and the hippocampus (below)

 

THE LATEST DISCOVERIES …

Thanks to the major technological advancement in the field of neuroscience, and to the development of genetic engineering, it is now possible to make experiments that tantalize our imagination and that have allowed us to discover exciting data related to memory.
Here just an example: using a very precise technique called “optogenetics“, researchers inject specific proteins into some neurons of specific mice and with a laser they can “turn on” or “turn off” these neurons, thereby controlling their activity and activating the memory in a context that would otherwise not be reactivated.
Thanks to this new technique, the group of Paul Frankland in Toronto, Canada, has discovered that the memories of the early years of our lives are not only created, during childhood but remain in our brains far into adulthood; they simply become inaccessible.

The reason why the brain keeps these memories but makes them inaccessible is still a mystery, but it is precisely what neuroscientists are now aiming to discover.

This video shows some neurons get activated…


P.S: If you are curious and want to find out more, please visit the website: www.donatolab.com. To him, I say a special thanks for the photo, the video, and for helping me to write this post.

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