The major contribution of this work is examining the changes in cerebrovascular changes in migraine patients and control group due to the effect of a mental activity and comparing the amount of changes in blood oxygenation with healthy subjects to show the neurovascular coupling disorder and have a better understanding of the physiological changes in the brain during mental work. An experimental protocol is designed, to generate a higher activity in the prefrontal cortex by using a cognitive task, which is composed of three difficulty levels, and to measure the activation differences between healthy and diseased (migraine) subjects. In this study, the hemodynamic response during mental arithmetic task was evaluated in both healthy subjects and migraine patients and these responses were compared among these two groups. Our specific hypothesis was that "The hemodynamic response increases with the increasing working memory load in all subjects and this increase would be somewhat impaired in migraine patients according to the neurovascular coupling disorder hypothesis of migraine.