Amplitudes of motor evoked potentials are modulated by EEG oscillations

2018 Fiscal Year Final Research Report

• Project/Area Number: 16K01963
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Brain biometrics
• Research Institution: Kyushu University
• Principal Investigator: Ogata Katsuya 九州大学, 医学研究院, 講師 (50380613)
• Research Collaborator: NAKAZONO Hisato ; TOBIMATSU Shozo
• Project Period (FY): 2016-04-01 – 2019-03-31
• Keywords: 経頭蓋磁気刺激 / 運動誘発電位 / 脳波 / オシレーション / 周波数分析

Outline of Final Research Achievements

Motor evoked potentials (MEPs) by transcranial magnetic stimulation (TMS) are often used to estimate the excitability of primary motor cortex (M1). However, MEP amplitudes fluctuate after every TMS. The underlying neural substrates are not fully understood, thus we analyzed the relationship of electroencephalography (EEG) and MEP amplitudes. EEGs were recorded while single pulse TMS were delivered, and MEPs were obtained after every TMS.
EEGs before TMS were analyzed, and we revealed that α-β band powers are related to MEP amplitudes. When α-β power was higher at the time of TMS, the MEP amplitudes were larger. In addition, the EEG-MEP relationship were observed during eyes-open state, but not eyes-closed state. Therefore, we revealed that EEG-MEP relationship is observed in α-β band in a state dependent manner.

Free Research Field

臨床神経生理学

Academic Significance and Societal Importance of the Research Achievements

一次運動野に対する経頭蓋磁気刺激で得られる運動誘発電位(MEP)は刺激毎に大きく振幅が変動する。MEP振幅は広く一次運動野興奮性の指標として用いられるが、その変動により評価の感度が下がるため、MEP振幅変動またその主な要因と考えられる一次運動野興奮性変動の神経基盤解明はMEP計測全般に重要性がある。また安静時の皮質興奮性変動の機序は近年MRI研究などでも注目を集めており、本研究も安静時の皮質興奮性変動の神経基盤の解明に寄与するものと考えられる。今回得られた結果により脳波の周波数特異的なMEP振幅への影響が明らかとなり、更にこれまで注目されて来なかった開閉眼での効果が明らかとなった。