From experience to memory: the magical hippocampus

From experience to memory: the magical hippocampus

MRI  with highlight marking the right hippocampus

Now, I’ll be short and will point you to some resources to confirm the facts in my science-fiction novel. 

Let me start this short bit about (episodic/semantic) memory formation from dispelling an old myth: memories are not recorded and stored. The vocabulary that used to be used for memory processes since the 1980s in cognitive psychology had it wrong (because we didn’t know enough about memory) and the words stuck. It is more correct to think of memory as a continuous process. Why? Because a new memory – unless you’re a newborn – is not created in a vacuum. The brain always has some related experiences to link it to, recall and update when new information comes in. Therefore, memory formation and transformation are continuous spiralling processes that shape our live stories. 

Concept neurons: fact or fiction?

You may be surprised, but “Jennifer Anniston” or “granma” neurons are a fact! Reported for the first time in 2005 by Prof. Rodrigo Quian Quiroga et al., concept neurons in the medial temporal lobe (MTL) code visual representations of a concept that is invariable of the way in which it is presented. This discovery paved the way to understanding how information (visual experiences) are encoded in the memory-forming part of the brain. 

It means that the hippocampal cells represent meaning – a very high level of semantically processed information. It also means that information we can make meaning of is remembered better as it is represented with its own specific neural cells.

How do we recall?

I’m skipping a few steps in forming a memory to take you straight to a layman explanation of memory reconstruction. 

Memory is reconstructive

It means that – sadly – every time you try to re-construct a memory – there is room for errors. And after every recall, the memory risks becoming updated with the inadvertent inaccuracies, false new information and lost details. 

Here’s a PDF “How do we recall childhood memories” 

The sight of a familiar person or the sound of this person’s voice, for example, triggers a cascade of brain processes that creates a representation leading to the recognition of the person and the recollection of details related to him or her. How is this possible? The holistic retrieval of complex event memories is thought to be the hallmark of episodic memory, underpinning the ‘recollective’ experience.

From “Reactivated Memories : Yusuké Y. Offhause / Ewa A Miendlarzewska”, 2018