Recently, the Blue Brain Project published a paper arguing that human neurons don't form synapses at locations determined by learning, but just wherever they bump into each other. See video and article here.
For those people hoping to upload their brains by mapping out and virtually duplicating all the synapses—this means that won't work. The synapse locations do not differ from human to human in any useful way. Learning must be encoded in some modulation of each synapse's function.