Aging interferes central control mechanism for eccentric muscle contraction.
Previous studies report greater activation in the cortical motor network in controlling eccentric contraction (EC) than concentric contraction (CC) despite lower muscle activation level associated with EC vs. CC in healthy, young individuals. It is unknown, however, whether elderly people exhibiting increased difficulties in performing EC than CC possess this unique cortical control mechanism for EC movements. To address this question, we examined functional magnetic resonance imaging (fMRI) data acquired during EC and CC of the first dorsal interosseous (FDI) muscle in 11 young (20-32 years) and 9 old (67-73 years) individuals. During the fMRI experiment, all subjects performed 20 CC and 20 EC of the right FDI with the same angular distance and velocity. The major findings from the behavioral and fMRI data analysis were that (1) movement stability was poorer in EC than CC in the old but not the young group; (2) similar to previous electrophysiological and fMRI reports, the EC resulted in significantly stronger activation in the motor control network consisting of primary, secondary and association motor cortices than CC in the young and old groups; (3) the biased stronger activation towards EC was significantly greater in the old than the young group especially in the secondary and association cortices such as supplementary and premotor motor areas and anterior cingulate cortex; and (4) in the primary motor and sensory cortices, the biased activation towards EC was significantly greater in the young than the old group. Greater activation in higher-order cortical fields for controlling EC movement by elderly adults may reflect activities in these regions to compensate for aging-related impairments in the ability to control complex EC movements. Our finding is useful for potentially guiding the development of targeted therapies to counteract age-related movement deficits and to prevent injury.
Department of Kinesiology, Health, and Nutrition, College of Education and Human Development, The University of Texas at San Antonio San Antonio, TX, USA.
Wan X
WX
Yao
Research Imaging Institute, The University of Texas Health Science Center at San Antonio San Antonio, TX, USA.
Jinqi
J
Li
Human Performance and Engineering Laboratory, Kessler Foundation Research Center West Orange, NJ, USA ; Department of Biomedical Engineering, New Jersey Institute of Technology Newark, NJ, USA.
Zhiguo
Z
Jiang
IDG/McGovern Institute for Brain Research, Peking University Beijing, China.
Jia-Hong
JH
Gao
Research Imaging Institute, The University of Texas Health Science Center at San Antonio San Antonio, TX, USA.
Crystal G
CG
Franklin
Department of Kinesiology, Health, and Nutrition, College of Education and Human Development, The University of Texas at San Antonio San Antonio, TX, USA.
Yufei
Y
Huang
Research Imaging Institute, The University of Texas Health Science Center at San Antonio San Antonio, TX, USA.
Jack L
JL
Lancaster
Human Performance and Engineering Laboratory, Kessler Foundation Research Center West Orange, NJ, USA.
Guang H
GH
Yue
brain activation; concentric contraction; eccentric contraction; fMRI; movement stability