It's all in the timing

Abstract

Timing is crucial to many aspects of human performance – from catching a cricket ball to delivering a punch line. A recent study sheds new light on the identity of the brain's timekeeper [Rao, S.M. et al. (2001) Nature Neurosci. 4, 317–323]. Subjects were asked to compare the time intervals between two pairs of sounds. Using event-related fMRI, the researchers were able to separate out activation occurring at different stages of the task. Activation after the first pair of sounds reflected encoding of timing information, whereas later activation associated with comparison of the time intervals reflected more general processes of decision making and response preparation. Early activation was detected in the basal ganglia and right parietal cortex. This concurs with the observation that people with Parkinson's disease, which affects dopamine transmission in the basal ganglia, are impaired with regard to time perception. By contrast, activation of the cerebellum, which is often hypothesized to be the brain's timekeeper, was detected only later in the task. HJB