Differences in blood flow between auditory and visual stimuli in the Psychomotor Vigilance Task and GO/NOGO Task.

The Psychomotor Vigilance Task (PVT) and the GO/NOGO task are generally applied to measure the ability of sustained attention. Advances in functional brain imaging equipment, such as functional Magnetic Resonance Imaging (fMRI) and functional Near-Infrared Spectroscopy (fNIRS), have resulted in increased application of brain imaging with these tasks. However, several different stimuli are adopted in these tasks, including both auditory and visual stimuli. Therefore, even when a subject performs these tasks, it can be assumed that the activated brain regions would vary when the different stimuli are given. Furthermore, even when a subject performs the tasks with the same sustained attention, the activated brain regions would vary when the configurations of these tasks are different. In this study, the reaction time and changes in blood flow were measured when a subject performed the PVT and GO/NOGO tasks, and so it is possible to discuss (1) the differences between visual and auditory stimuli and (2) the differences between PVT and GO/NOGO tasks. The results indicated increased blood flow at the left side of the dorsolateral prefrontal cortex in the PVT with visual stimulus compared with the auditory stimulus. In the GO/NOGO task, the blood flow associated with visual stimuli increased at the both sides of the inferior temporal gyrus and the right side of the inferior frontal gyrus compared with auditory stimuli. These observations suggested that the configurations of these tasks, such as the PVT and the GO/NOGO tasks, exert influences on the activated brain regions when a subject performs these tasks.