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Sponsored by: |
National Institute of Neurological Disorders and Stroke (NINDS) |
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Information provided by: | National Institutes of Health Clinical Center (CC) |
ClinicalTrials.gov Identifier: | NCT00357058 |
This study will examine the role of different brain regions in tactile (touch) ability after application of a tourniquet (inflated blood pressure cuff). When the forearm is deprived of blood for a short period of time, tactile ability in the other hand improves. This study will try to learn what causes this improvement.
Healthy normal volunteers are eligible for this study. Candidates will have a brief medical history and physical examination.
Volunteers will undergo two experiments, described below, that involve the following procedures:
Experiment 1
This experiment measures changes in tactile acuity and brain activation following cuff inflation. The subject lies in the MRI scanner, with the left arm immobilized. Tactile acuity is measured repetitively at the left index finger during placement and inflation of a pressure cuff around the right forearm. The experiment consists of two sessions with the cuff around the forearm and one with the cuff around the calf and lasts from 90 minutes to 2 hours.
Experiment 2
This experiment measures changes in tactile acuity linked to TMS stimulation. The subject sits in an armchair with the left arm immobilized. Tactile acuity is measured repetitively at the left index finger during placement and inflation of a pressure cuff around the right forearm. In addition, TMS pulses (about one pulse per second) are delivered at different locations over the right side of the head for up to 30 minutes. The experiment consists of 10 separate sessions on different days, each lasting about 1 hour.
Condition |
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Tactile Spatial Acuity Healthy |
Study Type: | Observational |
Official Title: | Substrates Mediating Deafferentiation-Induced Enhancement of Tactile Spatial Acuity |
Estimated Enrollment: | 90 |
Study Start Date: | December 2001 |
Estimated Study Completion Date: | December 2007 |
Acute deafferentation in one hand leads to improvements in tactile discriminative skills in the other, non-deafferented hand. This phenomenon, recently identified in our laboratory, represents an adaptive, behaviorally important consequence of deafferentation. It demonstrates that acute loss of sensory input from one hand results in rapid improvement of skills in the remaining hand. The first experiment in this protocol seeks to identify cortical regions activated in association with this improvement in tactile spatial acuity. In the second experiment, we will determine the effects of transient inactivation of focal cortical regions on this behavioral gain. While the first experiment will characterize brain regions activated in association with this performance improvement, the second experiment will provide information on the functional role of these regions. Understanding the substrates that mediate this behavioral gain may be important for the design of strategies to enhance them.
Ages Eligible for Study: | 18 Years and older |
Genders Eligible for Study: | Both |
Accepts Healthy Volunteers: | No |
Normal volunteers who are willing and able to remain relaxed and immobile during active scans, for a period of up to 2 hours.
EXCLUSION CRITERIA:
Subjects with: metal in the cranium except for crowns or fillings in mouth and permanent metal dental braces, metal fragments from occupational exposure or surgical clips in or near the brain.
Subjects with eye, blood vessel, cochlear or eye implants, with increased intracranial pressure as evaluated by clinical means, with cardiac or neural pacemakers, intracardiac lines and/or implanted medication pumps.
Subjects with large hemorrhagic or brain stem stroke.
Subjects with multiple cerebral lesions with residual deficits.
Subjects with history of head injury with loss of consciousness.
Subjects with history of severe alcohol or drug abuse or psychiatric illness.
Subjects with unstable cardiac dysrhythmia or unresponsive arterial hypertension (greater than 160/100 mmHg).
Subjects with history of hyperthyroidism or individuals receiving drugs acting primarily on the central nervous system or disorders of the blood coagulation system.
Subjects with excessive callus at their fingers.
Preganant women will be excluded from the study.
SUBJECTS DISCONTINUATION CRITERIA:
Subject's poor compliance with protocol evaluations or examinations and subject's request to withdraw.
Study ID Numbers: | 020079, 02-N-0079 |
Study First Received: | July 26, 2006 |
Last Updated: | March 5, 2008 |
ClinicalTrials.gov Identifier: | NCT00357058 |
Health Authority: | United States: Federal Government |
Deafferentiation-Induced Plasticity fMRI Cortical Reorganization Tactile Performance Transcranial Magnetic Stimulation |
Tactile Discrimination Plasticity Healthy Volunteer HV Normal Control |
Healthy |