I think you vastly overestimate our current understanding of the brain/neuronal processing, even singular (neuron) cell's workings. The fMRI enthusiasm turned out wrong a long time ago and there hasn't been much progress since, for all I know. And knowing a gene sequence wasn't enough either. We are still lacking theory big time. For most all of biology, we do not understand anything fully really. Not in neuro science, not in evolution theory, and god forbid not in genetics. Complex != complicated. Complexity is a hard barrier. We do not have abstraction for emergence, merely still recording thing's reactions when you poke them in different ways.