Cortical and subcortical contributions to the representation of temporal information

• Published in: Neuropsychologia 2003, Vol.41 (11), p.1461-1473
• Main Authors: Handy, Todd C, Gazzaniga, Michael S, Ivry, Richard B
• Format: Article
• Language: English
• Subjects: Adult and adolescent clinical studies; Basal ganglia; Biological and medical sciences; Callosotomy; Cerebellum; Cerebral Cortex - physiology; Cerebral Cortex - physiopathology; Corpus callosum; Corpus Callosum - physiology; Corpus Callosum - physiopathology; Corpus Callosum - surgery; Discrimination Learning - physiology; Epilepsy - physiopathology; Epilepsy - surgery; Functional Laterality - physiology; Hemispheric asymmetry; Humans; Male; Medical sciences; Mental Processes - physiology; Middle Aged; Organic mental disorders. Neuropsychology; Photic Stimulation; Psychology. Psychoanalysis. Psychiatry; Psychopathology. Psychiatry; Split-brain; Time perception; Time Perception - physiology; Visual Fields - physiology
• ISSN: 0028-3932; 1873-3514
• DOI: 10.1016/S0028-3932(03)00093-9

Converging evidence suggests that temporal representations of brief durations are derived subcortically. We tested split-brain patient JW in order to investigate whether these representations project bilaterally or unilaterally to cortex. Using visual stimuli to signal time intervals, JW was asked to compare the duration of a pair of standard stimuli that were presented bilaterally with a comparison stimulus that was presented to either the left or right visual field. Assuming the hand of response is controlled by the contralateral cerebral hemisphere, a hand by visual field interaction was predicted if the representation of stimulus duration was restricted to the cerebral hemisphere receiving the lateralized stimulus. However, we failed to observe this interaction for two different ranges of stimulus durations, both in the hundred (Experiment 2) to hundreds (Experiment 1) of milliseconds range. Instead, there was a consistent right hemisphere advantage in task performance. When the task then required a discrimination based on the physical size of the stimuli rather than their duration, an interaction between response hand and visual field was obtained (Experiment 3). Taken together, these results suggest that (1) even though the comparison stimulus was presented unilaterally, the representation of its duration was available to both cerebral hemispheres, and (2) a right hemisphere advantage in psychophysical tasks requiring the comparison of successive stimuli is observed for temporal and non-temporal judgments.