If we had a simple, throw it in a box for five years, stable memristor, we'd have everything we'd need for brain modeling. Being as a memristor is effectively a synapse.
With that, we would want to do everything in the analog domain anyways.
[0] the other three are the resistor, the capacitor, and the inductor.
I can't seem to find anything on memristors being on chip or really being in solid state anything.
I would love to get my hands on them!
It was possible to buy memristor storage devices, but they weren't sufficiently competitive with ordinary flash memory and I believe they're relegated to niche applications such as high erase counts.
AI implementations on Memristor circuitry has come up often enough that even I've heard of it. E.g.: A random recent development is https://www.nature.com/articles/s41467-024-45312-0