Memories are made of 'matter', in particular of a molecule similar to DNA, the 'Rna', which, if transferred from one animal to another, allows to transmit the 'engram', the mnemonic trace of the first to the second animal . This is what was suggested by an experiment conducted with sea snails by David Glanzman at the University of Los Angeles (UCLA) and published in the journal eNeuro. What forms memories has remained something very elusive; for a long time it was believed that the memory traces remained engraved on the communication bridges (synapses) between neurons and that the formation and consolidation of a memory corresponded to the formation of new synapses. Recent studies, on the other hand, have opened the doors to another possibility, namely that the formation of memory is mediated by the production of specific Rna molecules, with corresponding changes in the activity of genes.
In other words, it is assumed that the memory is stored in a specific Rna molecule, like a microscopic memory card. The study on sea snails goes in this direction: Glanzman has in fact demonstrated that by transferring a specific molecule of Rna taken from one snail to another one can transfer the memory of the first to the second snail. Specifically, Glanzman first induced the formation of a (negative) memory in a snail by touching the tail in order to annoy the animal which, by reflex, has an involuntary defensive reaction. Then he isolated the RNA that was generated in his nervous system following the nagging experience and inoculated it into a second animal whose tail had never been solicited. Well, the latter stages the same defensive reflex as the former while not having suffered any discomfort in the tail, only because it had received the memory (in the form of Rna) of the first animal.