The role of tactile sensation in online and offline hierarchical control of multi-finger force synergy

Kyung Koh, Hyun Joon Kwon, Bum Chul Yoon, Yongseok Cho, Joon Ho Shin, Jin Oh Hahn, Ross H. Miller, Yoon Hyuk Kim, Jae Kun Shim

Research output: Contribution to journalArticlepeer-review

13 Citations (Scopus)


The hand, one of the most versatile but mechanically redundant parts of the human body, must overcome imperfect motor commands and inherent noise in both the sensory and motor systems in order to produce desired motor actions. For example, it is nearly impossible to produce a perfectly consistent note during a single violin stroke or to produce the exact same note over multiple strokes, which we denote online and offline control, respectively. To overcome these challenges, the central nervous system synergistically integrates multiple sensory modalities and coordinates multiple motor effectors. Among these sensory modalities, tactile sensation plays an important role in manual motor tasks by providing hand-object contact information. The purpose of this study was to investigate the role of tactile feedback in individual finger actions and multi-finger interactions during constant force production tasks. We developed analytical techniques for the linear decomposition of the overall variance in the motor system in both online and offline control. We removed tactile feedback from the fingers and demonstrated that tactile sensors played a critical role in the online control of synergistic interactions between fingers. In contrast, the same sensors did not contribute to offline control. We also demonstrated that when tactile feedback was removed from the fingers, the combined motor output of individual fingers did not change while individual finger behaviors did. This finding supports the idea of hierarchical control where individual fingers at the lower level work together to stabilize the performance of combined motor output at the higher level.

Original languageEnglish
Pages (from-to)2539-2548
Number of pages10
JournalExperimental Brain Research
Issue number9
Publication statusPublished - 2015 Sept 18

Bibliographical note

Funding Information:
The research was funded in part by National Research Foundation (NRF-2013004812) of Korea and the Translational Research Center for Rehabilitation Robots, Korea National Rehabilitation Center, Ministry of Health & Welfare, Korea (NRCTR-EX15007). We thank the collaborators at the Applied NeuroDynamics Lab, Korea University, for their assistance in experiments.

Publisher Copyright:
© 2015, Springer-Verlag Berlin Heidelberg.


  • Finger
  • Motor redundancy
  • Synergy
  • Tactile feedback

ASJC Scopus subject areas

  • General Neuroscience


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