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Brain Inhibition of Muscle Movement in Normal Volunteers

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: NCT00047957
Recruitment Status : Completed
First Posted : October 23, 2002
Last Update Posted : March 4, 2008
Information provided by:
National Institutes of Health Clinical Center (CC)

Brief Summary:

This study will use transcranial magnetic stimulation, or TMS (described below), to examine how the brain controls muscle movement to prevent unwanted movements in surrounding muscles. For example, when a person moves a finger, a part of the brain called the cortex prevents unwanted movements in other fingers by a process called cortical inhibition. In people with the muscle disorder dystonia, cortical inhibition does not work properly and patients suffer from uncontrolled and sometimes painful movements. A better understanding of how this process works in normal people may shed light on what goes wrong in dystonia and how the condition can be treated.

Healthy normal volunteers 19 years of age and older may be eligible for this study. Candidates will be screened with a medical history and physical and neurological examinations. People with a current medical or surgical condition or neurological or psychiatric illness may not participate, nor may individuals who are taking medication that may influence nervous system function.

Participants will undergo TMS to record the electrical activity of muscles in the hand and arm that are activated by magnetic stimulation. For the procedure, subjects are seated in a chair with their hands placed on a pillow in their laps. A wire coil in placed on their scalps. A brief electrical current is passed through the coil, creating a magnetic pulse that stimulates the brain. Subjects will be asked to move their second finger in response to a loud beep or visual cue. In some trials, a brief, mild electrical shock will also be applied to the end of either the second or fifth finger. The shock is not painful.

TMS may cause muscle, hand or arm twitching if the coil is near the part of the brain that controls movement, or it may induce twitches or temporary tingling in the forearm, head, or face muscles. The twitching may cause mild discomfort, but the procedure is rarely considered painful.

Condition or disease
Dystonic Disorders

Detailed Description:
The purpose of this study is to investigate the effect of homotopic and heterotopic sensory afferent input on surround inhibition in the motor cortex. Surround inhibition is a cortical phenomenon, the function of which may be to suppress unwanted movements in surrounding muscles during voluntary actions. In support of this, a recent study showed that motor output to the little finger was reduced during self-paced, voluntary movements of the index finger, despite an increase in spinal excitability. Work has also shown that in relaxed muscle, homotopic and heterotopic peripheral stimulation results in time dependent modulation of motor cortical excitability. However, no studies have examined the relationship between volitional movement and afferent sensory input on cortical surround inhibition. Therefore, the aim of this study is to examine the changes in surround inhibition when electrical stimulation is applied to either the finger being actively moved (homotopic stimulation) or a separate finger not involved in the movement (heterotopic stimulation) at different time periods prior to the initiation of movements to assess the affect of these stimuli on surround inhibition and excitation in the motor cortex.

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Study Type : Observational
Enrollment : 20 participants
Official Title: The Effect of Peripheral Homotopic and Heterotopic Stimulation on Cortical Excitability
Study Start Date : October 2002
Study Completion Date : September 2005

Resource links provided by the National Library of Medicine

MedlinePlus related topics: Dystonia

Information from the National Library of Medicine

Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the contacts provided below. For general information, Learn About Clinical Studies.

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


Twenty healthy volunteers older than age 18 will be recruited for the study. Their gender, age, or ethnic origin will not provide bias for inclusion to the study. All subjects will sign an informed consent prior to participation in the trial.


Exclusion criteria for the trial will include any current medical or surgical condition or neurological or psychiatric illnesses. Furthermore, any individual who is on medication with potential influence on nervous system function, who has a pacemaker, an implanted medical pump, a metal plate or metal object in the skull or eye (for example, after brain surgery), or who has a history of seizure disorder will be excluded from the trial.

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): NCT00047957

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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)
Layout table for additonal information Identifier: NCT00047957    
Other Study ID Numbers: 030008
First Posted: October 23, 2002    Key Record Dates
Last Update Posted: March 4, 2008
Last Verified: September 2005
Keywords provided by National Institutes of Health Clinical Center (CC):
Motor Cortex
Afferent Stimulation
Transcranial Magnetic Stimulation
Healthy Volunteer
Additional relevant MeSH terms:
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Dystonic Disorders
Movement Disorders
Central Nervous System Diseases
Nervous System Diseases
Neurologic Manifestations