Abstract
[Purpose] The purpose of this study was to observe the surface cerebral blood flow related to associative reaction in the legs. [Subjects and Methods] The subjects were 20 male adults. The participants performed isometric resistance abduction movement of the right hip joint. The intensity of the resistance was 80% of the maximum muscular strength. Contraction of the left gluteus medius was checked by EMG to judge the associative reaction. The surface cerebral blood flow of the motor area of the frontal lobe during the task was measured using functional near- infrared spectroscopy. [Results] The surface cerebral blood flow on the left side of the primary motor area and both sides of the premotor area significantly increased during the task. [Conclusion] Even though the associative reaction in the left leg was an involuntary muscular contraction, the activity of the premotor area of the right side during the task was confirmed.
