I'm not an expert but... Fly brains and human brains already have have neural networks for common tasks, like sensing motion, baked into our genetics. Evolution has already trained these networks to an extent. Training a computer-simulated neural network seems to yield similar results to what nature has done.
My personal uninformed opinion is that we'll start to see how much human experience and expression is driven by our brain wiring. That we'll discover how similar we all are to each other based our wiring. And that we'll find that approximating advanced cognition will be the result of putting that wiring into a computer model -- and having a computer powerful enough to run it.