technically when you are born, the mappings are all over the place and as you age, part of the development process is to prune down the connections that are inefficient, or what would we deem as incorrect (only due to we regard what is correct to be what most people have, which is the most efficient mapping).
so until that happens, babies get visual output when they hear sounds, and shit like that.
schizophrenia is when normal nerve response triggers too wide a range of a reaction in the nerves around it.
like bad insulation on a wire - but not really since the wire definition is incorrect in terms of a neuron (a series of dominos falling over is a better analogy)