Cortical involvement in temporal reproduction: evidence for differential roles of the hemispheres.

Only few studies have addressed temporal processing for durations longer than 1 s, and even fewer studies have investigated cortical involvement in time perception, in particular temporal production and reproduction. The present study investigated temporal reproduction in healthy control subjects and patients with anterior or posterior cortical lesions in the left or right hemisphere, or with subcortical left-hemispheric lesions. The paradigm involved presentation of either auditory or visual stimuli of 10 different standard intervals ranging from 1 to 5.5 seconds duration. Participants were required to reproduce the duration of a stimulus. Our results show that: (1) temporal reproduction across this temporal range can be better described with two separate linear regressions (bilinear approach) than with one single linear regression, thus contrasting the scalar timing concept; (2) that patients can, regardless of the hemisphere lesioned, perform reproductions of durations smaller than 2-3 s with reasonable accuracy; and (3) that patients with right-hemispheric lesions appear to be impaired in reproductions of stimuli longer than 2-3 s. Since attention appeared not to be impaired in the patients tested, the findings suggest that the integrity of the right hemisphere seems to be critical for temporal reproduction of intervals longer than 2-3 s.