What could go wrong?

The computing power needed to build the model is phenomenal. Simply to replicate one of the 10,000 neuron brain cells involved in the rat experiment took the processing capacity usually found in a single laptop. To simulate a fully functioning human brain, it would take billions.

Hill says that such computational power — known as exascale — will be available by the end of the decade. The Human Brain Project’s scientists are hoping to work with supercomputer developers to ensure future machines match their requirements.

But, even as the team touts its experiments as a possible solution to the brain diseases that affect about two billion people worldwide, they have attracted critics who say their work is far too broad in scope to achieve usable results.