The Organization of Goal-Directed Behaviour in the Brain

Professor John Duncan FRS MRC - A.V. Hill Lecture Our behaviour is characteristically organized in a hierarchical structure of goals and subgoals, with many fragments of behaviour contributing to an everyday activity such as making breakfast or attending a lecture. Such goal-directed structures are often impaired following major damage to the frontal lobes of the brain. I shall describe a core discovery of human brain imaging – a nine-patch network recruited for addressing a very broad range of cognitive challenges, based in frontal cortex but with additional components elsewhere. This network is strongly activated by a standard test of “fluid intelligence”, known to predict success in all kinds of activities and presumably requiring mental operations of very widespread importance. From human brain imaging, I shall move on to electrophysiology in the behaving monkey. In a network of frontal lobe regions, putatively homologous to regions of the human network, I shall show encoding of core components of a goal-directed plan – current state, goal, component moves and hierarchy. Damage to this network, I suggest, underlies the broad behavioural impairment that can follow frontal lobe damage.