Memories are stored in the brain, but it is not really clear where exactly they are, how they look, what they are made of. Evolutionary neurobiologist Nikolai Kukushkin - about memory and whether it can be transplanted.
Scientists like the idea of memory transplant almost as much as science fiction writers. But the creators of Black Mirror and other works that discuss the possibility of sharing memories are concerned with practical and ethical issues, and from the point of view of neurobiology, this procedure is tempting in itself - as a scientific result. If memory can really be transplanted, then it is physically contained in what is transplanted. Whoever carries out the transfer of memories will make a discovery on a global scale.
Places of memory
The answers to the question of where the memory is located were one after the other. Many would say that memory is hidden in the hippocampus, the part of the brain without which memories of events are not formed. But the hippocampus is required only for a special form of memorization, characteristic of humans and related animals: episodic, or autobiographical, memory. However, over time, even such memory seems to "move" into the cerebral cortex. In addition, many things, such as skills, are formed without the participation of the hippocampus, and some animals do not have it at all, like other parts of the brain similar to humans.
Memory is also located in the connections between nerve cells. And in special enzymes that support the excitation of these cells. And in cellular programs that regulate the work of genes. And in special prion proteins (not those prions that cause mad cow disease). And in the cellular factories, ribosomes, which assemble proteins according to genetic instructions, memory is also contained.
All these answers look contradictory. The more scientists know about memory, the more philosophical questions arise: what is memory in general and, in particular, what does it mean to transplant it. In fact, there is no contradiction. In any memorization - no matter in which gyrus and in which animal - there is something in common, fundamental, embedded in the evolutionary logic of the nervous system. Gradually, all of the above methods and levels of storing information began to take shape: memory is not so much an object as an aggregate state.
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Memory as the history of the brain
When the brain perceives the world, something inside changes. These changes affect how the brain continues to perceive the world. Some changes quickly disappear, others last longer, new ones are layered on them, on which subsequent transformations depend, and so on. At any given time, all these changes - both long-term and short-term - represent what we think of as memory.
It turns out that memory does not "lie" anywhere and it is impossible to "shift" it. It is a current reflection of the cumulative history of specific brain regions, neurons and molecules. The brain does not "contain" memory - it is memory.
This is obvious from everyday experience. If memory could be extracted and projected onto a screen, as in Black Mirror, it would mean that we remember reality objectively, like a video camera. But memory doesn't work that way. Some things are remembered well, some are bad: the brain, unlike a video camera, decides what to remember and what not.
Not only does the brain remember very selectively, we remember not reality as such, but the state of the brain at the moment of perception. The source can be around events or emotions, motivations, other memories. Recalling, we partially bring the brain back to its previous state - and with this reproduction, “internal” sources are inseparable from “external” ones. Accordingly, my memory is exactly my memory and no one else's, because no one else has exactly the same brain to bring it to the same state. There is nothing to copy and nowhere.
But is everything so simple? How did sea snails, frightened by electric shock, question the usual view of nerve cells? Why do neurons during training "infect" each other with particles that look like viruses? Read about all this in the full article by Nikolai Kukushkin on the popular science site "Attic".