近赤外線脳酸素モニタを利用したタッピング動作中の皮質活動について

抄録

Objectives: the purpose of this study was clarify the brain related activation area that are involved in five different extension index finger tapping (EIFT) task using near infrared spectroscopy (NIRS) as well as the relationship between the cerebral activation and the movement frequency.
Methods: The subjects were laid in a comfortable chair in a semi-darkened shielded room with their eyes closed and instructed to be awake We measured the regional cerebral hemodynamics using 24-channel NIRS to see the changes in oxi-, deoxi-, and the total- hemoglobin from 6 neurologically health subjects under five different EIFT task. These are: 100% of maximal effort (ME) with maximal EIFT, 100% of ME with minimum EIFT, 50% of ME with maximal EIFT, 50% of ME with minimum EIFT and a random EIFT task. To determine the frequency at an individual’s ME, all subjects underwent the ME trial during maximum amplitude of movement. The subject’s index finger was set-up to have the extension movement free and the wrist and the others fingers were immobilized by strap. Each flexion movement of the index finger was accompanied by a beep produced by the equipment and the amplitude of the movement was kept asking to the subject to touch a ruler set up above of the finger. Five cycles were performed and each of the finger tapping cycles lasted 20 s, followed by a 40 s rest period. Electromyography (EMG) from finger extensor muscle (extensor indicis muscle) was recorded.
Results: all subjects showed activation in motor control area during 100% of ME with maximal EIFT much more than others tasks as well as the EMG showed significant magnitude difference. It’s means that tapping with ME with maximal EIFT is directly related to the cerebral activation in motor cortex area.
Conclusion: these results demonstrated that the rate of change in motor control area at a ME during maximal EIFT task was much higher than that a low frequency EIFT tasks.