Dimensional complexity of neuromagnetic activity reduced during finger movement of greater difficulty

Yu Zu Wu, Ting Hui Yang, Yung Yang Lin, Shyan Shiou Chen, Kwong Kum Liao, Li Fen Chen, Tzu Chen Yeh, Yu Te Wu, Low Tone Ho, Jen Chuen Hsieh

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Abstract

Objective: We investigated the variation in dimensionality (D2) of neuromagnetic activity over the primary sensorimotor cortex (SM1) in healthy adults performing motor tasks of different difficulty. Methods: Magnetoencephalography (MEG) was used to record neuromagnetic activity during self-paced, brisk unimanual finger extension at a rate of 1 and 2 Hz using the index finger of the dominant and non-dominant hands in 16 healthy subjects. Motor task difficulty was rated by the relative difference in time measurement between 1 and 2 Hz finger movements of both hands. The relative difference in dimensionality of SM1 activity was calculated by subtracting the D2 value in 2 Hz movement from that in 1 Hz one within subjects. Results: Simple regression analyses show a significantly negative relationship between the relative dimensional complexity and the relative motor task difficulty in the contralateral SM1 for the left- (p < 0.05), but not the right- (p = 0.447) hand movement. Conclusions: The present data suggest that a motor task of greater difficulty may engender a reduction of simultaneously active quasi-independent neuronal generators in the contralateral SM1 underpinned by stronger neuronal connectivity of a relatively low dimensionality. Significance: The decrease in dimensional complexity of MEG activity associated with a motor task of greater difficulty gives new insights to motor control strategy.

Original languageEnglish
Pages (from-to)2473-2481
Number of pages9
JournalClinical Neurophysiology
Volume117
Issue number11
DOIs
Publication statusPublished - 2006 Nov 1

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Keywords

  • Correlation dimension
  • Hemispheric asymmetry
  • Magnetoencephalography
  • Neuronal connectivity
  • Nonlinear dynamics
  • Task difficulty

ASJC Scopus subject areas

  • Sensory Systems
  • Neurology
  • Clinical Neurology
  • Physiology (medical)

Cite this

Wu, Y. Z., Yang, T. H., Lin, Y. Y., Chen, S. S., Liao, K. K., Chen, L. F., Yeh, T. C., Wu, Y. T., Ho, L. T., & Hsieh, J. C. (2006). Dimensional complexity of neuromagnetic activity reduced during finger movement of greater difficulty. Clinical Neurophysiology, 117(11), 2473-2481. https://doi.org/10.1016/j.clinph.2006.06.715