Sadly the metaphor doesn't hold. I heard somewhere that something like 19 petaflops is roughly equivalent of the processing power required. I don't recall exact

Sadly the metaphor doesn't hold. I heard somewhere that something like 19 petaflops is roughly equivalent of the processing power required. I don't recall exactly from whose arse that number managed egress but I suspect it's more on the mark. Obviously 1e15 transistors is not going to give you that. A transistor makes a bad neuron. Neurons have complex behaviour in and of themselves, and maintain various kinds of state that persist after action potentials (i.e. after firing.) Transistors don't do that individually, so the analogy is quite bogus. Not only that, but connections between (synapses) are not as trivial as a simple wire and even engage in two-way communications. Considering each neuron may have multiple inbound and outbound connections, sometimes over (relatively) vast distances, counting the neurons alone is inaccurate. And I haven't even gotten to diffuse signals. There's a lot of overhead.