(Of course we might still learn useful things from such a model, I just want to be clear that it wouldn't in any sense be a complete one.)
It isn't enough to flip switches on and off, and to recognize weights, or even to take a fully formed brain network and simulate it. You have to understand how it developed, what it reacts to, how body shapes mind shapes body, and so on and so forth.
What we're doing now with NN's is mistaking them for the key to making an artificial consciousness, when all we're really playing with is the ML version of one of those TI calculators with the paper roll the accountants and bookkeepers use. They are subunits that may compose together to represent xmcrystalized functional units of expert system logic; but they are no closer to a self-guided, self-aware entity than a toaster.
Minimally, whatever the complexity inside a Biological neuron maybe, one fundamental propery we need to obtain is thr connection strengths for the entire connectome, which we don't have. Without that we actually don't know the full connectome even of the simplest organisms, and no one to my knowledge has hence actually studied the kind of algorithms that are running in these systems. I would love to be corrected here of xourse.