[cbennett]

Overall, you are right in your diagnosis - we simply have not located a single mechanism responsible for memory. In reality, it is probably a collective effect due to a huge maelstrom of chemical computing. Our brain is one of the most imposing dynamical systems ever studied! That's why the mathematics and in turn modeling of it is so beastly.

Right now there are broadly speaking two camps in neuroscience, those who are connectionists and believe that memories are overall rather non-volatile/physically localized, with an MIT group that showed particular (individual ) neurons linked to particular memories, at the extreme of that school. On the other hand, you have neuroscientists who subscribe to a more plastic conception- in which mass synchronizations and redundant information is consistently combined and recombined.

My take is that it is no contradiction to admit the our brain is clearly volatile, and non-volatile in different modes. The transition from STP (short term memory) to LTP (long term memory) probably involves different conformational changes in neurons, dendrites, who knows even on the epigentic scale. But we do know the volatility is important and interesting-- which is precisely what makes this diffusive memristive study so important!