Understanding neural anatomy and physiology depends on first understanding the behaviour being mediated. Glover, in his review of earlier work suggesting various dichotomies in visual processing, shows how there is a tendency to oversimplification if this approach is ignored. His own new proposals demonstrate the advantages of allowing function to drive anatomical analysis. Nevertheless, the new planning–control dichotomy he proposes, though a valuable advance, is itself an oversimplification of what must be a multi-channel system.
