Human spinal circuits related to finger movements

2022 Fiscal Year Final Research Report

• Project/Area Number: 19K19827
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 59010:Rehabilitation science-related
• Research Institution: Yamagata University
• Principal Investigator: Nito Mitsuhiro 山形大学, 医学部, 助教 (70732692)
• Project Period (FY): 2019-04-01 – 2023-03-31
• Keywords: 運動制御 / 脊髄反射 / 筋電図 / 電気刺激 / 上肢

Outline of Final Research Achievements

To elucidate the relationship between wrist and hand movements, we measured the wrist-bending force, maximal grip/pinch force, and finger function tests in subacute stroke patients. The wrist-bending force produced by maximal isometric force was decreased in all directions in individuals with motor paralysis. In addition, delayed finger movements and reduction of maximal force were observed in these subjects. We also investigated the effects of electrical stimulation to the radial nerve innervating extensor carpi radialis (ECR) on motoneurons supplying intrinsic and extrinsic hand muscles in healthy volunteers. We found that monosynaptic facilitation mediated by group Ia afferents originated from muscle spindles of ECR to these motoneruons exists in human spinal cord. Enhancing these spinal circuits may contribute to the recovery of finger motor function after stoke.

Free Research Field

リハビリテーション科学

Academic Significance and Societal Importance of the Research Achievements

本研究は、急性期脳卒中患者の手根と手指機能の関連を調べ、リハビリテーションへの応用の可能性を探る基礎的な研究である。手根の力は麻痺側において、どの方向でも減弱しており、手指運動の遅延・機能低下を認めた。健常者でヒトの脊髄神経機構について調べたところ、橈側手根伸筋から手指筋の運動細胞に対して単シナプス性促通を持つことが明らかとなった。以上から、手根伸筋群への介入により手指運動機能を改善させる可能性があることが示唆された。