Basal ganglia: racing to say no

How we choose one action over another has intrigued neuroscientists for decades. Early models of decision-making involved a race between processes representing alternative choices. To explain behaviour in complex decisions, for example, where one must cancel an impending action, a Stop unit must also join the race. Recent neuronal recordings have demonstrated just such a race between Go and Stop processes in the basal ganglia. This is a landmark advance because it neurophysiologically justifies the need for a Stop process in such tasks, and very likely in other behaviours requiring rapid cancellation of impending actions.