Citation

McGinley M, Hoffman RL, Russ DW, Thomas JS, Clark BC. Exp. Gerontol. 2010; 45(9): 671-678.

Affiliation

Institute for Neuromusculoskeletal Research; Department of Biomedical Sciences.

Copyright

(Copyright © 2010, Elsevier Publishing)

DOI

10.1016/j.exger.2010.04.005

PMID

20417265

PMCID

PMC2926152

Abstract

BACKGROUND: Aging results in decreased neuromuscular function, which is likely associated with neurologic alterations. At present little is known regarding age-related changes in intracortical properties. Methods In this study we used transcranial magnetic stimulation (TMS) to measure intracortical facilitation (ICF), short- and long-interval intracortical inhibition (SICI and LICI), motor evoked potential amplitude, and silent period duration in young and older adults (21.4+/-0.8yrs and 70.9+/-1.8yrs). These variables were assessed from the flexor carpi radialis muscle of the non-dominant arm under resting conditions, and during a submaximal contraction (intensity 15% maximum strength). RESULTS: Older adults exhibited increased SICI and LICI in comparison to young adults (SICI: 29.0+/-9.2% vs. 46.2+/-4.8% of unconditioned pulse; LICI: 6.5+/-1.7% vs. 15.8+/-3.3% of unconditioned pulse; p=0.04), and less ICF under resting conditions (74.6+/-8.7% vs. 104.9+/-6.9% of unconditioned pulse; p=0.02). These age-related differences disappeared during contraction, although the older adults did exhibit a longer silent period during contraction (112.5+/-6.5 vs. 84.0+/-3.9msec; p<0.01). CONCLUSIONS: Collectively, these findings suggest increased GABA mediated intracortical inhibition with age.

Language: en