TITLE: AGING AND LEARNING OF NOVEL FINE MOTOR TASKS ABSTRACT Older adults are expected to comprise 25% of the workforce in the US by the year 2050 1, 2. Successful employment of older adults and subsequent maintenance of their independence and health depends on their ability to perform and learn novel motor tasks with accuracy 1. The effects of human aging on cognition 3 and fine motor performance have been studied extensively 4. Nonetheless, the interaction of the age-associated motor impairments and ability to learn and retain novel motor tasks is not well understood 8, 9. Based on our preliminary work, we hypothesize that the ability of older adults to learn novel fine motor tasks is compromised 5, 6 due to altered agonist-antagonist activation 5 and that training that emphasizes alternating agonist- antagonist activity will improve the ability of older adults to retain and transfer novel motor tasks 7, 85. The hypothesis will be tested with three specific aims. The first two specific aims will identify neuromuscular mechanisms that contribute to the impaired ability of older adults to learn and transfer novel motor tasks during single-joint movements. The first experiment (Aim 1) will identify the agonist-antagonist adaptations that occur in young and older adults at the single motor unit level when learning and transferring dexterous motor tasks with the index finger. The second experiment (Aim 2) will identify the neural adaptations that occur in young and older adults at the agonist-antagonist muscle level when learning and transferring novel aiming motor tasks. The third experiment (Aim 3) will extend the findings to a multi-joint task and determine the efficacy of a speed-progressive light-load training protocol in improving the ability of older adults to learn and transfer fine novel motor tasks with single-joint and multi-joint movements. We expect to find that the ability of older adults to learn, retain, and transfer fine novel motor tasks with accuracy is impaired because of altered activation of the agonist-antagonist motor neuron pool. This impairment in activation will be evident at the single motor unit and whole muscle level and will be exacerbated during multi-joint movements. Finally, we expect that the proposed speed-progressive light-load training will improve the ability of older adults to perform, retain, and transfer fine novel motor tasks with single-joint and multi-joint movements. The findings of this project, therefore, could have a significant impact on the development of motor rehabilitation strategies for young and older adults, as well for individuals who suffer from neurological disorders that impair movement accuracy.

Public Health Relevance

The ability to learn new motor tasks is a fundamental adaptive component of life. Consequently older adults who cannot adapt to changing environments by learning new motor tasks will loose their independence and health. Furthermore, older adults are expected to comprise 25% of the workforce in the US by the year 2050 1, 2. It is crucial, therefore, to understand how the healthy aging neuromuscular system learns to accomplish accurate movements and identify ways to improve the ability of older adults to learn and perform motor tasks with accuracy. The findings of this project, therefore, will identify neuromuscular mechanisms that contribute to motor learning and could have a significant impact on the development of training protocols and motor rehabilitation strategies for young and old adults.

Agency
National Institute of Health (NIH)
Institute
National Institute on Aging (NIA)
Type
Research Project (R01)
Project #
5R01AG031769-05
Application #
8316200
Study Section
Motor Function, Speech and Rehabilitation Study Section (MFSR)
Program Officer
Chen, Wen G
Project Start
2008-09-30
Project End
2014-08-31
Budget Start
2012-09-01
Budget End
2014-08-31
Support Year
5
Fiscal Year
2012
Total Cost
$194,598
Indirect Cost
$58,045
Name
University of Florida
Department
Physiology
Type
Schools of Allied Health Profes
DUNS #
969663814
City
Gainesville
State
FL
Country
United States
Zip Code
32611
Kwon, MinHyuk; Chen, Yen-Ting; Fox, Emily J et al. (2014) Aging and limb alter the neuromuscular control of goal-directed movements. Exp Brain Res 232:1759-71
Fox, Emily J; Moon, Hwasil; Kwon, MinHyuk et al. (2014) Neuromuscular control of goal-directed ankle movements differs for healthy children and adults. Eur J Appl Physiol 114:1889-99
Chen, Yen-Ting; Kwon, MinHyuk; Fox, Emily J et al. (2014) Altered activation of the antagonist muscle during practice compromises motor learning in older adults. J Neurophysiol 112:1010-9
Moon, Hwasil; Kim, Changki; Kwon, Minhyuk et al. (2014) Force control is related to low-frequency oscillations in force and surface EMG. PLoS One 9:e109202
Vaillancourt, David E; Christou, Evangelos A (2013) Slowed reaction time during exercise: what is the mechanism? Exerc Sport Sci Rev 41:75-6
Onushko, Tanya; Baweja, Harsimran S; Christou, Evangelos A (2013) Practice improves motor control in older adults by increasing the motor unit modulation from 13 to 30 Hz. J Neurophysiol 110:2393-401
Clark, David J; Kautz, Steven A; Bauer, Andrew R et al. (2013) Synchronous EMG activity in the piper frequency band reveals the corticospinal demand of walking tasks. Ann Biomed Eng 41:1778-86
Fox, Emily J; Baweja, Harsimran S; Kim, Changki et al. (2013) Modulation of force below 1 Hz: age-associated differences and the effect of magnified visual feedback. PLoS One 8:e55970
Kennedy, Deanna M; Christou, Evangelos A (2011) Greater amount of visual information exacerbates force control in older adults during constant isometric contractions. Exp Brain Res 213:351-61
Kwon, MinHyuk; Baweja, Harsimran S; Christou, Evangelos A (2011) Age-associated differences in positional variability are greater with the lower limb. J Mot Behav 43:357-60

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