Individual preferences in motor coordination seen across the two hands: relations to movement stability and optimality

Paulo B. de Freitas, Sandra M.S.F. Freitas, Mechelle Lewis, Xuemei Huang, Mark Latash

Research output: Contribution to journalArticle

Abstract

The framework of the uncontrolled manifold (UCM) hypothesis was used to explore variables related to stability of task performance in the two hands of young healthy individuals. Fourteen young adults performed four-finger accurate constant force production tasks interrupted by a voluntary quick force pulse production and by an externally imposed displacement of all fingers. Three groups of variables were used to quantify stability of steady force production: (1) indices of the inter-trial variance were computed within the UCM and orthogonal to the UCM; (2) indices of motor equivalence were computed between steady-state intervals separated by the force pulse and by the finger-lifting episode; and (3) referent coordinate and apparent stiffness were computed using the data during the ascending phase of the finger-lifting episode. In another task, the subjects performed accurate constant force production with visual feedback removal after the 8th second, and the drop in the total force after the removal was computed. There were differences between the right and left hand in some outcome variables such as variance within the UCM, and the timing of anticipatory synergy adjustments prior to the force pulse, consistent with the dynamic dominance hypothesis. There were significant correlations between the two hands for indices that were unrelated to accuracy of performance: variance within the UCM, index of motor equivalence, referent coordinate, apparent stiffness, and the drop of total force after visual feedback removal. We interpret these findings within the concept of stability–optimality trade-off. In particular, we conclude that individual subjects select particular, person-specific solutions within the spectrum allowed by the explicit task constraints, and this choice is consistent between the two hands. We conclude with a hypothesis that selecting specific solutions within the stability–optimality trade-off may represent an individual’s personal preference consistent between the two hands.

Original languageEnglish (US)
JournalExperimental Brain Research
Volume237
Issue number1
DOIs
StatePublished - Jan 31 2019

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Hand
Fingers
Sensory Feedback
Social Adjustment
Task Performance and Analysis
Advisory Committees
Young Adult

All Science Journal Classification (ASJC) codes

  • Neuroscience(all)

Cite this

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title = "Individual preferences in motor coordination seen across the two hands: relations to movement stability and optimality",
abstract = "The framework of the uncontrolled manifold (UCM) hypothesis was used to explore variables related to stability of task performance in the two hands of young healthy individuals. Fourteen young adults performed four-finger accurate constant force production tasks interrupted by a voluntary quick force pulse production and by an externally imposed displacement of all fingers. Three groups of variables were used to quantify stability of steady force production: (1) indices of the inter-trial variance were computed within the UCM and orthogonal to the UCM; (2) indices of motor equivalence were computed between steady-state intervals separated by the force pulse and by the finger-lifting episode; and (3) referent coordinate and apparent stiffness were computed using the data during the ascending phase of the finger-lifting episode. In another task, the subjects performed accurate constant force production with visual feedback removal after the 8th second, and the drop in the total force after the removal was computed. There were differences between the right and left hand in some outcome variables such as variance within the UCM, and the timing of anticipatory synergy adjustments prior to the force pulse, consistent with the dynamic dominance hypothesis. There were significant correlations between the two hands for indices that were unrelated to accuracy of performance: variance within the UCM, index of motor equivalence, referent coordinate, apparent stiffness, and the drop of total force after visual feedback removal. We interpret these findings within the concept of stability–optimality trade-off. In particular, we conclude that individual subjects select particular, person-specific solutions within the spectrum allowed by the explicit task constraints, and this choice is consistent between the two hands. We conclude with a hypothesis that selecting specific solutions within the stability–optimality trade-off may represent an individual’s personal preference consistent between the two hands.",
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Individual preferences in motor coordination seen across the two hands : relations to movement stability and optimality. / de Freitas, Paulo B.; Freitas, Sandra M.S.F.; Lewis, Mechelle; Huang, Xuemei; Latash, Mark.

In: Experimental Brain Research, Vol. 237, No. 1, 31.01.2019.

Research output: Contribution to journalArticle

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T1 - Individual preferences in motor coordination seen across the two hands

T2 - relations to movement stability and optimality

AU - de Freitas, Paulo B.

AU - Freitas, Sandra M.S.F.

AU - Lewis, Mechelle

AU - Huang, Xuemei

AU - Latash, Mark

PY - 2019/1/31

Y1 - 2019/1/31

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