Localisation of function in the brain: a rethink

A modular view of brain function dominates the teaching of medical students and clinical psychologists and is implicit in day-to-day clinical practice. This view glosses over a long-standing debate. The extent of one-to-one mappings between region and function remains a controversial topic. For the cortex, localisation of function versus ‘cerebral equipotentiality’ was debated less than 150 years ago, and traces of this debate remain active in systems neuroscience today. The advent of functional brain imaging led to an explosion of evidence on localisation of function studied in vivo, and a gold rush to map an ever-increasing range of ‘functions’. Rapid growth in knowledge was accompanied, to some extent, by a flourishing neuromythology. There are currently few clinical applications of brain mapping techniques, but new areas are emerging. An understanding of the central debate on functional localisation will bring a more nuanced view of problems encountered in clinical practice.