Decision making: From sensory evidence to a motor command

In his famous remark, Mark Twain articulates the basic fact that making decisions takes time. What happens in the brain that takes so much time? In an illuminating recent study, Gold and Shadlen [1] used electrical stimulation of the brain to probe the evolution of a perceptual choice. They found that preparation of the movement that will signal the choice proceeds in proportion to the quality and duration of the sensory evidence on which the choice is based. Furthermore, a quantitative model links a formal representation of the sensory stimulus with the decision and motor planning process.