The numbers seem to suggest that it's a simple mechanic - hey just 302 neurons - but a single neuron cell is immensely complex, containing millions of molecules, trillions of atoms that all interact with each other in unknown, unpredictable or even unobservable ways. Even if we had all that data in a model, the biggest problem is that our computations, unlike nature's, are done serially, meaning we only get to work at one bit at a time whereas nature is computing all of the interactions in parallel. If you've ever done a physics collision system you'd know how the performance starts to degrade rapidly with just very few elements (being an O(n^2) problem) and you need to make workarounds. So we need different hardware to start with, like analog computers, if we'd ever have a chance to simulate a single living cell (for starters), then move on to larger organisms.