I don't have access to the original paper right now, but Dave does do good stuff, he's no crank, and I'd believe him for the time being. A possibility to what

I don't have access to the original paper right now, but Dave does do good stuff, he's no crank, and I'd believe him for the time being. A possibility to what is occurring is that the RNA is 'interfering' somehow with the DNA synthesis. The synapse is very tightly regulated and getting receptors/transmitters into it may be affected by the production of the proteins in the first place (or the 'state' of the receptors, ie actelyation, methylation, etc). Under this idea, a memory is just the memristive state of the synapse, controlled by the populations of transmitters and receptors (all occurring in a network of neurons and synapses). The RNA may be affecting that downstream network during the DNA>RNA phase. But, I've not read the paper and seen their controls yet. I'd assume Dave really went all out on the controls. I'm a mammalian/zebrafish guy, and my snail anatomy isn't that robust anymore, and I've not read the paper yet, so I don't really know. Histone methylation is a real thing and a cause of some epigenic phenomena, so I'd think something like this is the culprit. Still, this is a really surprising result, and (sorry to sound like a broken record) more research in needed.