I believe that even what many people describe as immaterial soul/mind is in fact the result of a trillion neurons triggering each other, with diverse strengths. Take two persons; even a small difference in how their brain neurons connect to each other and how they trigger each other might produce a different way of thinking and a different behavior. At least that's what my (mathematical) gut feeling tells me!

All that remains is to find the way to accurately map all the neurons and connections, try to replicate it and see what happens...