Brain function involves information processing across a wide range of scales, from sub-cellular signalling cascades to neuronal networks spanning many centimetres, and on timescales from the millisecond duration of an action potential up to the maintenance of information in memory over a human lifetime. Physics helps to provide insight into the general principles governing information processing in the brain, across these scales. Research groups within this theme are particularly active in collecting large-scale neural recording data, and analysing it using approaches derived from statistical physics, network and information theory, in using mathematical tools to study learning and memory, in studying how brain activity changes during sleep and anaesthesia, and in studying how the brain copes with uncertainty and noise when processing information.