Modulations in corticospinal excitability accompanying contraction-mode conversion during joint movements

Research Project

Project/Area Number	26750308
Research Category	Grant-in-Aid for Young Scientists (B)
Allocation Type	Multi-year Fund
Research Field	Sports science
Research Institution	Waseda University (2017-2018) The University of Tokyo (2016) Niigata University of Health and Welfare (2014-2015)
Principal Investigator	Higashihara Ayako 早稲田大学, スポーツ科学学術院, 助教 (90724237)
Research Collaborator	Nakagawa Kento Nakazawa Kimitaka
Project Period (FY)	2014-04-01 – 2019-03-31
Project Status	Completed (Fiscal Year 2018)
Budget Amount *help	¥2,730,000 (Direct Cost: ¥2,100,000、Indirect Cost: ¥630,000) Fiscal Year 2015: ¥780,000 (Direct Cost: ¥600,000、Indirect Cost: ¥180,000) Fiscal Year 2014: ¥1,950,000 (Direct Cost: ¥1,500,000、Indirect Cost: ¥450,000)
Keywords	皮質脊髄路興奮性 / 伸張性収縮 / 短縮性収縮 / 皮質脊髄路 / 経頭蓋磁気刺激 / 橈骨主根屈筋 / 運動制御 / 筋疲労 / 磁気刺激
Outline of Final Research Achievements	The present study investigated phasic modulation in corticospinal excitability during wrist joint movements. Participants performed single, rapid wrist movements by resisting and lifting weights connected to a dynamometer through a pulley system. Single transcranial magnetic stimulation was applied at random times before and after wrist movement conversion. The differences between before (LEN phase) and after (CON phase) wrist movement conversion for the corresponding symmetric angles were compared. Current results suggest that during the LEN phase before the wrist movement conversion, the inhibitory component of the corticospinal pathway was relatively higher than that during SHO contractions.
Academic Significance and Societal Importance of the Research Achievements	スポーツ活動時に多く発生する「肉離れ」の受傷には，素早い筋収縮の切り替え時に起こる神経筋協調機能の失調が密接に関与していると考えられる．本研究によって，素早い筋収縮制御時における皮質脊髄路興奮性の変調特性が明らかとなり，中枢神経系と筋がどのような機序で協調性を取り合い，筋収縮様式の素早い切り替えを遂行しているのか，その一端が明らかになった．本研究成果は、ヒトの日常動作やスポーツ活動時における中枢神経系の運動制御機構解明において重要な基礎的知見となると期待される．