Distributed neural systems for temporal production: a functional MRI study.

Using functional magnetic resonance imaging (fMRI), we investigated the neural substrates for computing time intervals. Five right-handed males were asked to judge if a digit probe belonged to a string of digits presented immediately before but to provide their response only after 1.5s had elapsed. This time estimation condition, compared with control working memory and motor tasks, was associated with increased activity in the middle occipital gyri, in the right inferior parietal lobe, and bilaterally in the prefrontal cortex. We argue that activity elicited in the occipital lobe provides duration information about visual stimuli that can be quantified at the level of the inferior parietal lobe. Comparison with time reference information depends on the bilateral prefrontal cortex.