Context-Dependent Neural Modulations in the Perception of Duration

Recent neuroimaging studies have revealed that two distinct brain networks are recruited in the perception of sub-second and supra-second durations. The aim of this study is to examine how intermediate duration between sub- and supra-second, that is, around one second duration, is processed in our brain. We hypothesized that durations around one second can be processed either by the sub-second system or by the supra-second system in a context-dependent matter; when the one-second stimuli are presented in the context of sub-second processing, the one-second stimuli would be processed by the sub-second system, and when they are presented in the context of supra-second processing, then, they would be processed by the supra-second system. To test our hypothesis, we measured neural correlates during the perception of duration by using functional magnetic resonance imaging (fMRI). Seventeen subjects were asked to reproduce durations of the visually presented stimuli by pressing a button. The stimulus duration was either sub-second, one-second, or supra-second. In half of the scans, trials of the one-second duration were intermixed with the trials of the sub-second durations, and in another half of the scans, trials of the one-second duration were intermixed with the trials of the supra-second durations. Firstly, we replicated previous studies by showing the separate neural networks recruited for the sub- and supra-second perceptions; visual cortex, premotor, SMA, and cerebellum for the sub-second perception, and insula and basal ganglia for the supra-second perception. Secondly, when one-second stimulus was presented with the sub-second stimulus, the visual cortex and cerebellum exhibited greater activations compared to when the stimulus was presented with the supra-second stimulus. The present results suggest that the durations around one-second could be processed either by the sub- and the supra- second system, and the visual cortex plays a part in such context-dependent modulations. Meeting abstract presented at VSS 2015.