NEURONAL MECHANISM OF ALTERED RESPONSE TIME DURING THE DUAL WARNING TASK

Motor functions are planned and inhibited until a specific cue in daily life. This inhibition has been studied using magnetic resonance imaging (MRI), primarily through action-cancel tasks, which assesses the ability to cancel improper actions rather than the movement preparation. This study aims to examine the effect of movement preparation in response to cues presented in two different temporal patterns. We conducted functional MRI to investigate the brain activation associated with the dual-warning task. Twenty-one healthy young adults (16 males and 5 females; age 22.52 ± 0.88 years) participated in the experiment. As the task, we presented two visual stimuli before the target stimuli as the cue. Participants were asked to inhibit the reaction until the target stimuli were presented. For the unified condition, the stimulus interval between the cue and the target was fixed, and to make the task difficult, we used 300ms jitter as the variable condition. The reaction time in the unified condition was significantly faster than that in the variable condition. The positive brain response was observed in the supplementary motor area, precentral gyrus, parietal/central operculum, Pallidum, orbital inferior frontal gyrus, and anterior insula. Both conditions, however, didn’t showed significant defference in the activation. In this task, the attentional and motor-control rerated regions were activated, and the 300ms jitter affected only the behavioral data. Our task for movement preparation showed different brain activation patterns than the action cancel tasks in the previous study, and even with 300ms jitter applied, they are consistent in activating the brain.