you have to first understand and be able to simulate the neuron and how it makes decisions and then reproduce the neurotome (the dude below calls it connectome but I have always liked neurotome) or how neurons connect to each other
there are a couple of dudes working on that that I have seen talk
Sebastian Seung is mapping a massively ambitious new model of the brain that focuses on the connections between each neuron. He calls it our "connectome," and it's as individual as our genome -- and understanding it could open a new way to understand our brains and our minds.
Sebastian Seung is a leader in the new field of connectomics, currently the hottest space in neuroscience, which studies, in once-impossible detail, the wiring of the brain.
Henry Markram says the mysteries of the mind can be solved -- soon. Mental illness, memory, perception: they're made of neurons and electric signals, and he plans to find them with a supercomputer that models all the brain's 100,000,000,000,000 synapses.
Henry Markram is director of Blue Brain, a supercomputing project that can model components of the mammalian brain to precise cellular detail -- and simulate their activity in 3D. Soon he'll simulate a whole rat brain in real time.