Spinal Reflexes in Motor Skill Learning

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details. Identifier: NCT00076583
Recruitment Status : Completed
First Posted : January 27, 2004
Last Update Posted : March 4, 2008
Information provided by:
National Institutes of Health Clinical Center (CC)

Brief Summary:

This study will test a spinal cord reflex called reciprocal inhibition before, during, and after learning a motor skill to see if the reflex becomes stronger by learning the movement. People learn new motor skills throughout their lives. At first, performing a new skilled movement such as riding a bicycle takes effort and is clumsy, but with practice, it becomes relatively automatic. The motor cortex (a part of the brain) is very active when a new skilled movement is learned, but becomes less active when the movement is over-learned. This study will determine whether the spinal cord helps coordinate the pattern of activity between groups of muscles once a motor skill is learned.

Healthy volunteers between 21 and 65 years of age may be eligible for this study. Candidates are screened with a medical history and neurological examination.

Participants are divided into two groups. Group 1 has movement training sessions only and Group 2 has both movement training sessions and physiology sessions, as follows:

Movement training sessions

For 15 minutes every weekday, participants practice moving their wrist back and forth to make a cursor on the computer screen follow a target. Activity of the arm muscles is monitored with surface electrodes taped to the skin. The sessions continue until the participant can perform the movement well. Group 1 participants return to the clinic a week after the last session to perform the movement again to see if their skill level has changed. Each session lasts about 20 to 30 minutes.

Physiology sessions

In three separate sessions, the reflex for reciprocal inhibition is measured before and at several times during the movement task. This is done with nerve conduction studies. A probe placed on the skin delivers a low-intensity electrical stimulus. Wires taped to the skin record the nerve impulses. To measure reciprocal inhibition, several dozen stimuli are given to two nerves in combinations. Each session lasts 2 to 3 hours.

Condition or disease

Detailed Description:


Once a skilled movement is thoroughly learned, it can be performed relatively automatically. The motor cortex is active when learning a new motor skill, but becomes less activated once the skill has become over-learned. We hypothesize that learning a skilled movement is associated with more efficient use of subcortical motor circuits. Subcortical motor circuits can coordinate features of the intended movement such as the timing and patterns of activation of different muscles. The goal of this study is to determine whether learning a motor skill strengthens spinal interneuron circuits that facilitate the movement. Subjects will learn to perform a movement consisting of alternating wrist movements. The strength of reciprocal inhibition between antagonist muscles will be tested.

Study Population:

22 healthy adult volunteers


The study has two experiments. Both experiments use a within-subjects design. The purpose of the first experiment is to determine whether learning to accurately perform an alternating wrist flexion and extension movement task is associated with reduced co-contraction of wrist flexor and extensor muscles. Subjects will practice making accurate wrist flexions and extensions to keep a cursor on a target for fifteen-minute sessions every weekday until they are able to obtain 95% accuracy. Activity of the arm muscles will be monitored during the sessions with surface electrodes on the arm muscles. The first experiment will also determine the best training parameters for learning the task. In the second experiment, a second group of subjects will learn the task using the best training parameters. The strength of the reflex for reciprocal inhibition will be measured before, during and after training. Reciprocal inhibition will also be measured after the movement has become highly learned.

Outcome measures:

In the first experiment, the outcome will be the percent of movement time in which co-contraction occurs, as recorded from surface electrodes, while the subject learns to perform the movement to 95% accuracy. In the second experiment, the outcome measure is the strength of spinally mediated reciprocal inhibition, as measured using reflexes.

Study Type : Observational
Enrollment : 22 participants
Official Title: Motor Skill Learning: Spinal Reflexes
Study Start Date : January 2004
Study Completion Date : November 2005

Information from the National Library of Medicine

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Ages Eligible for Study:   Child, Adult, Senior
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   Yes


Healthy individuals between the ages of 21-65 years who are willing to participate in daily training sessions and physiological studies.


Any history of peripheral nerve injury, cervical radiculopathy, arthritis, tendonitis, or surgery on the wrist.

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its identifier (NCT number): NCT00076583

United States, Maryland
National Institute of Neurological Disorders and Stroke (NINDS)
Bethesda, Maryland, United States, 20892
Sponsors and Collaborators
National Institute of Neurological Disorders and Stroke (NINDS)