PT  - JOURNAL ARTICLE
AU  - Tsuyoshi Ikegami
AU  - Gowrishankar Ganesh
AU  - Tricia L. Gibo
AU  - Toshinori Yoshioka
AU  - Rieko Osu
AU  - Mitsuo Kawato
TI  - Hierarchical motor adaptations negotiate failures during force field learning
AID  - 10.1101/2020.07.16.207084
DP  - 2020 Jan 01
TA  - bioRxiv
PG  - 2020.07.16.207084
4099  - http://biorxiv.org/content/early/2020/07/17/2020.07.16.207084.short
4100  - http://biorxiv.org/content/early/2020/07/17/2020.07.16.207084.full
AB  - Humans have the amazing ability to learn the dynamics of the body and environment to develop motor skills. Traditional motor studies using arm reaching paradigms have viewed this ability as the process of ‘internal model adaptation’. However, the behaviors have not been fully explored in the case when reaches fail to attain the intended target. Here we examined human reaching under two force fields types; one that induces failures (i.e., target errors), and the other that does not. Our results show the presence of a distinct failure-driven adaptation process that enables quick task success after failures, and before completion of internal model adaptation, but that can result in persistent changes to the undisturbed trajectory. These behaviors can be explained by considering a hierarchical interaction between internal model adaptation and the failure-driven adaptation of reach direction. Our findings suggest that movement failure is negotiated using hierarchical motor adaptations by humans.Competing Interest StatementThe authors have declared no competing interest.