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Directed connectivity between primary and premotor areas underlying ankle force control in young and older adults

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DOI

  • Meaghan Elizabeth Spedden, University of Copenhagen
  • ,
  • Mikkel Malling Beck, University of Copenhagen
  • ,
  • Mark Schram Christensen, University of Copenhagen
  • ,
  • Martin Dietz
  • Anke Ninija Karabanov, University of Copenhagen
  • ,
  • Svend Sparre Geertsen, University of Copenhagen, Denmark
  • Jens Bo Nielsen, University of Copenhagen
  • ,
  • Jesper Lundbye-Jensen, University of Copenhagen
The control of ankle muscle force is an integral component of walking and postural control. Aging impairs the ability to produce force steadily and accurately, which can compromise functional capacity and quality of life. Here, we hypothesized that reduced force control in older adults would be associated with altered cortico-cortical communication within a network comprising the primary motor area (M1), the premotor cortex (PMC), parietal, and pre-frontal regions. We examined electroencephalographic (EEG) responses from fifteen younger (20-26 yr) and fifteen older (65-73 yr) participants during a unilateral dorsiflexion force-tracing task. Dynamic Causal Modelling (DCM) and Parametric Empirical Bayes (PEB) were used to investigate how directed connectivity between contralateral M1, PMC, parietal, and prefrontal regions was related to age group and precision in force production. DCM and PEB analyses revealed that the strength of connections between PMC and M1 were related to ankle force precision and differed by age group. For young adults, bidirectional PMC-M1 coupling was negatively related to task performance: stronger backward M1-PMC and forward PMC-M1 coupling was associated with worse force precision. The older group exhibited deviations from this pattern. For the PMC to M1 coupling, there were no age-group differences in coupling strength; however, within the older group, stronger coupling was associated with better performance. For the M1 to PMC coupling, older adults followed the same pattern as young adults - with stronger coupling accompanied by worse performance - but coupling strength was lower than in the young group. Our results suggest that bidirectional M1-PMC communication is related to precision in ankle force production and that this relationship changes with aging. We argue that the observed age-related differences reflect compensatory mechanisms whereby older adults maintain performance in the face of declines in the sensorimotor system.
Original languageEnglish
PublisherbioRxiv
DOIs
Publication statusPublished - 15 Oct 2019

    Research areas

  • EEG, DCM, motor control, brain connectivity

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ID: 187635713