Evolution of hand and finger motions - between locomotion and manipulation

2020 Fiscal Year Final Research Report

• Project/Area Number: 19K22454
• Research Category: Grant-in-Aid for Challenging Research (Exploratory)
• Allocation Type: Multi-year Fund
• Review Section: Medium-sized Section 45:Biology at organismal to population levels and anthropology, and related fields
• Research Institution: Kyoto University
• Principal Investigator: HIRASAKI Eishi 京都大学, 霊長類研究所, 准教授 (70252567)
• Project Period (FY): 2019-06-28 – 2021-03-31
• Keywords: 手機能の進化 / 無標点運動解析 / バイオメカニクス / 圧分布解析 / 霊長類

Outline of Final Research Achievements

To understand the evolution of hand function, it is essential to explore the strategies that the hand has adopted to perform the two different roles of locomotion and manipulation. In this study, I attempted to analyze the biomechanics of hand movements during the performance of various tasks in primates, including humans, using markerless 3D motion analysis and pressure distribution analysis. Manipulation experiments suggest that the functional axis of the hand is medially shifted in humans compared to monkeys. From locomotion experiments, we found that the role of the thumb becomes more important in quadrupedal walking on a horizontal pole, which simulated arboreal locomotion, as compared with terrestrial walking. Although there is a delay due to COVID-19, I will continue to analyze the experimental data by feeding them into a control system model of hand movement which my collaborator and I have developed.

Free Research Field

生物学的人類学

Academic Significance and Societal Importance of the Research Achievements

本申請は、手指の動きについて、その進化的背景、すなわちロコモーション器官としての手を視野に入れ、ヒトを含む霊長類でバイオメカニクス解析を行うことで手の機能進化の探索を試みた最初の研究である。本研究の実験結果の分析が進めば、手の進化に関する新たな知見をもたらすのみならず、手指に関する人間工学や把握が重要な要素となるロボット工学、さらには手機能の病的低下や老化による低下に関する臨床医学領域に対して、重要な情報を提供できる可能性がある。