The energetic basis for smooth human arm movements

eLife

Jeremy D Wong¹  Arthur D Kuo¹  Tyler Cluff² 

[1] University of Calgary, Faculty of Kinesiology, Department of Biomedical Engineering, Calgary, Canada;University of Calgary, Faculty of Kinesiology, Department of Biomedical Engineering, Calgary, Canada;Hotchkiss Brain Institute, University of Calgary, Calgary, Canada;

关键词: motor control;    arm movements;    energetic cost;    optimal control;    minimum variance;    calcium pumping;    Human;   

DOI  :  10.7554/eLife.68013

来源: eLife Sciences Publications, Ltd

【 摘 要 】

The central nervous system plans human reaching movements with stereotypically smooth kinematic trajectories and fairly consistent durations. Smoothness seems to be explained by accuracy as a primary movement objective, whereas duration seems to economize energy expenditure. But the current understanding of energy expenditure does not explain smoothness, so that two aspects of the same movement are governed by seemingly incompatible objectives. Here, we show that smoothness is actually economical, because humans expend more metabolic energy for jerkier motions. The proposed mechanism is an underappreciated cost proportional to the rate of muscle force production, for calcium transport to activate muscle. We experimentally tested that energy cost in humans (N = 10) performing bimanual reaches cyclically. The empirical cost was then demonstrated to predict smooth, discrete reaches, previously attributed to accuracy alone. A mechanistic, physiologically measurable, energy cost may therefore explain both smoothness and duration in terms of economy, and help resolve motor redundancy in reaching movements.

【 授权许可】

CC BY