Living With Half A Brain

Tom Stafford considers what a woman who was born without a cerebellum — and lived a largely typical life — reveals about neuroscience:

This case points to a sad fact about brain science. We don’t often shout about it, but there are large gaps in even our basic understanding of the brain. We can’t agree on the function of even some of the most important brain regions, such as the cerebellum. Rare cases such as this show up that ignorance. Every so often someone walks into a hospital and their brain scan reveals the startling differences we can have inside our heads. Startling differences which may have only small observable effects on our behaviour.

Part of the problem may be our way of thinking. It is natural to see the brain as a piece of naturally selected technology, and in human technology there is often a one-to-one mapping between structure and function. If I have a toaster, the heat is provided by the heating element, the time is controlled by the timer and the popping up is driven by a spring. The case of the missing cerebellum reveals there is no such simple scheme for the brain. Although we love to talk about the brain region for vision, for hunger or for love, there are no such brain regions, because the brain isn’t technology where any function is governed by just one part.