REVERSE ENGINEERING

Decoding relies on the fact that correlations can be established between brain activity and the outside world. But Gallant and others want to do more; they want to work back to find out how the brain organizes and stores information in the first place — to crack the complex codes the brain uses.
That won’t be easy, says Gallant. Each brain area takes information from a network of others and combines it, possibly changing the way it is represented. Neuroscientists must work out post hoc what kind of transformations take place at which points. Unlike other engineering projects, the brain was not put together using principles that necessarily make sense to human minds and mathematical models. “We’re not designing the brain — the brain is given to us and we have to figure out how it works,” says Gallant. “We don’t really have any math for model
ling these kinds of systems.” Even if there were enough data available about the contents of each brain area, there probably would not be a ready set of equations to describe them, their relationships, and the ways they change over time.