As someone who's lab studies how memories are stored and recalled in the mamalian brain, I was excited to see a headline in the top list of Hacker News. Unfortu

As someone who's lab studies how memories are stored and recalled in the mamalian brain, I was excited to see a headline in the top list of Hacker News. Unfortunately, I was disappointed to see what was actually there. As is often the case, this article conflates some ideas that are truly remarkable and interesting (how are memories stored?) and mixes them with very strong statements that are clearly wrong. In this case, it is clear that synapses (connections between neurons) HAVE to be involved in memory, as the only way that a memory can ever be expressed is if a neuron triggers another neuron, etc, down the chain to a muscle. (OK, thoughts don't necessarily involve muscles, but to show your thoughts to the world.) And if synapse *dynamics* are not involved in memory, then either they never change, or they change randomly, both of which will lead to problems. (That's an exercise left to the reader.) So dynamic synapses are involved in memory, definitely, no question. The article mentions a couple of things that are interesting misdirection, like invertebrate models where "memories" are transmitted via serum. These are super cool experiments, but these are memories in the same way your immune system "remembers" a virus. Despite Tonegawa's best efforts, I think most researchers are quite confident that recalling your memory of last Christmas uses a very different mechanism than your immune system does to generate imagined tastes and smells and warm feelings. The article also talks about RNA ticker tapes. There is some super cool neuroengineering research around the idea of making a designer protein that would record a neurons activity in nucleotide chains as a readout. Definitely worth a dive if you're interested. And how neural activity drives synapse dynamics is a very big open question. It's known to involve protein synthesis (pkm-zeta, anyone?), so RNA is definitely involved. Finally, for those curious about how memories work, look up the "cognitive map" or the "index theory of memory".