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New evidence shows link between brain function and muscle strength

New evidence shows link between brain function and muscle strength

(ATHENS, Ohio – Nov. 24, 2014) Researchers at the Ohio University Heritage College of Osteopathic Medicine have found that mental imagery exercises can prevent muscles from getting weaker after not being used for extended periods of time. This finding has potential implications for patients undergoing neurorehabilitation, such as those who have suffered a stroke. It is also a major breakthrough for scientists and clinicians because it offers encouraging, new evidence about the role of the nervous system in muscle weakness.

Although imagery techniques are commonly used by professional athletes to improve their performance, this is the first study to show that imagery can play a role in stopping or slowing the loss of muscle strength following prolonged disuse. The results from the study are slated to be published later this fall in the Journal of Neurophysiology and are currently online at http://jn.physiology.org/content/early/2014/09/24/jn.00386.2014.

According to Brian Clark, Ph.D., professor of physiology and neuroscience at the Heritage College and executive director of the Ohio Musculoskeletal and Neurological Institute (OMNI), scientists have long known that the brain’s cortex helps coordinate and control muscle movement, but there was controversy about the link between the cortex and muscle strength. Clark describes muscles as the puppets of the nervous system and the brain as the string that makes muscles move.

“We wanted to tease out the underlying physiology between the nervous system and muscles to better understand the brain’s role in muscle weakness,” said Clark, who authored the article along with OMNI researchers Niladri Mahato, M.B.B.S.; Masato Nakazawa, Ph.D.; Timothy Law, D.O., M.B.A.; and James Thomas, P.T., Ph.D.

OMNI is an interdisciplinary institute that brings together scientists from several Ohio University colleges and schools to study disorders of the musculoskeletal and nervous systems. OMNI has strong programmatic efforts in two research divisions: 1) musculoskeletal and neurological pain disorders and 2) healthy aging. The research across these two divisions has an overarching aim of developing interventions that remove barriers to independent physical mobility and ultimately reduce disability.

“What our study suggests is that imagery exercises could be a valuable tool to prevent or slow muscles from becoming weaker when a health problem limits or restricts a person’s mobility,” said Clark. “The most impactful finding, however, is not the direct clinical application but the support that this work provides for us to better understand the critical importance of the brain in regulating muscle strength. This information may fundamentally change how we think about muscle weakness in the elderly.”

To test the brain’s connection to muscle strength, study participants had one arm immobilized in a cast for a month. Five times a week, they performed imagery exercises. In the exercise, researchers told participants to relax their forearm muscles and then imagine contracting their muscles and flexing their wrist. Researchers recorded participants’ muscle activity using an electromyogram (EMG).

Clark will be conducting additional research on muscle strength loss in an upcoming four-year project funded by the National Institutes of Health’s (NIH) National Institute on Aging. The study, officially named Unraveling the Neural Contributions of Dynapenia in Elders (The UNCODE Study), will use noninvasive techniques to better understand the connection between the brain, nervous system and muscles in the elderly.

The imagery study was primarily funded from a grant from the NIH’s Eunice Kennedy Shriver National Institute of Child Health and Human Development.

The Ohio University Heritage College of Osteopathic Medicine is a leader in training dedicated primary care physicians who are prepared to address the most pervasive medical needs in the state and the nation. Approximately 50 percent of Heritage College alumni practice in primary care and nearly 60 percent practice in Ohio. CARE LEADS HERE.