Bimanual motor coordination in older adults is associated with increased functional brain connectivity--a graph-theoretical analysis

PLoS One. 2013 Apr 29;8(4):e62133. doi: 10.1371/journal.pone.0062133. Print 2013.

Abstract

In bimanual coordination, older and younger adults activate a common cerebral network but the elderly also have additional activation in a secondary network of brain areas to master task performance. It remains unclear whether the functional connectivity within these primary and secondary motor networks differs between the old and the young and whether task difficulty modulates connectivity. We applied graph-theoretical network analysis (GTNA) to task-driven fMRI data in 16 elderly and 16 young participants using a bimanual coordination task including in-phase and anti-phase flexion/extension wrist movements. Network nodes for the GTNA comprised task-relevant brain areas as defined by fMRI activation foci. The elderly matched the motor performance of the young but showed an increased functional connectivity in both networks across a wide range of connectivity metrics, i.e., higher mean connectivity degree, connection strength, network density and efficiency, together with shorter mean communication path length between the network nodes and also a lower betweenness centrality. More difficult movements showed an increased connectivity in both groups. The network connectivity of both groups had "small world" character. The present findings indicate (a) that bimanual coordination in the aging brain is associated with a higher functional connectivity even between areas also activated in young adults, independently from task difficulty, and (b) that adequate motor coordination in the context of task-driven bimanual control in older adults may not be solely due to additional neural recruitment but also to aging-related changes of functional relationships between brain regions.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Aging / physiology
  • Biomechanical Phenomena
  • Brain / cytology
  • Brain / physiology*
  • Cerebrum / cytology
  • Cerebrum / physiology
  • Computer Graphics*
  • Female
  • Humans
  • Magnetic Resonance Imaging
  • Male
  • Middle Aged
  • Models, Neurological*
  • Motor Activity / physiology*
  • Nerve Net / cytology
  • Nerve Net / physiology*

Grants and funding

This work was supported by the Research Fund K.U. Leuven (OT/11/071); the Flanders Fund for Scientific Research (G.0483.10 and G.0721.12); the Interuniversity Attraction Poles program of the Belgian federal government (grant P6/29) (covered costs: salaries, MRI costs, operating budget). Marcus Heitger was funded by a Visiting Postdoctoral Fellowship of the Research Foundation Flanders (GP.004.10N) and an F+ Fellowship from the Research Fund K.U. Leuven (LHR-C1131-F+/09/022). Patrick Dupont is supported by Federaal Wetenschapsbeleid Belspo IUAP P6/29 and IWT-TBM 080658. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.