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Author Notes:

Correspondence: Keith M. McGregor, Department of Neurology; Emory University, 1518 Clifton Road NE, Decatur, GA 30033, USA. e-mail: keith.mcgregor@emory.edu

Disclosures: The contents do not represent the views of the Department of Veterans Affairs or the United States Government.

The authors report no actual or potential conflicts of interest.


Research Funding:

This work was supported by a Department of Veteran Affairs (VA) Rehabilitation R&D Center of Excellence #F2182C, Career Development Awards Level-1 (Keith M. McGregor; Joe R. Nocera), and Senior Research Career Scientist (Bruce Crosson: #B6364L) awards.


  • aging neuroscience
  • aging
  • fMRI
  • TMS
  • physical fitness
  • interhemispheric communication
  • negative BOLD
  • dexterity

Effects of Aerobic Fitness on Aging-Related Changes of Interhemispheric Inhibition and Motor Performance


Journal Title:

Frontiers in Aging Neuroscience


Volume 5, Number 66


Type of Work:

Article | Final Publisher PDF


Physical fitness has been long associated with maintenance and improvement of motor performance as we age. In particular, measures of psychomotor speed and motor dexterity tend to be higher in physically fit aging adults as compared to their sedentary counterparts. Using functional magnetic resonance imaging (fMRI) and transcranial magnetic stimulation (TMS), we explored the patterns of neural activity that may, in part, account for differences between individuals of varying physical fitness levels. In this study, we enrolled both sedentary and physically fit middle age (40–60) and younger (18–30) adults and measured upper extremity motor performance during behavioral testing. In a follow-up session, we employed TMS and fMRI to assess levels of interhemispheric communication during unimanual tasks. Results show that increased physical fitness is associated with better upper extremity motor performance on distal dexterity assessments and increased levels of interhemispheric inhibition in middle age adults. Further, the functional correlates of changes of ipsilateral activity appears to be restricted to the aging process as younger adults of varying fitness levels do not differ in hemispheric patterns of activity or motor performance. We conclude that sedentary aging confers a loss of interhemispheric inhibition that is deleterious to some aspects of motor function, as early as midlife, but these changes can be mediated by chronic engagement in aerobic exercise. Keywords: aging neuroscience, aging, fMRI, TMS, physical fitness, interhemispheric communication, negative BOLD, dexterity

Copyright information:

© 2013 McGregor, Nocera, Sudhyadhom, Patten, Manini, Kleim, Crosson and Butler.

This is an Open Access work distributed under the terms of the Creative Commons Attribution 3.0 Unported License (http://creativecommons.org/licenses/by/3.0/).

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