Monkeys that ‘draw’ reveal a neuronal population that encodes combinable actions

When faced with unfamiliar problems, humans and other animals must plan and execute action sequences that they might not have used before. In macaque monkeys, this ability is supported by a population of neurons in the brain’s frontal cortex that encode recombinable action units or ‘action symbols’. A figure-tracing task in monkeys provides clues to how the brain solves unfamiliar problems.