Role of Brain Region Changes in Tactile (Touch) Ability Following Nerve Block
|First Received Date ICMJE||July 26, 2006|
|Last Updated Date||March 5, 2008|
|Start Date ICMJE||December 2001|
|Primary Completion Date||Not Provided|
|Current Primary Outcome Measures ICMJE||Not Provided|
|Original Primary Outcome Measures ICMJE||Not Provided|
|Change History||Complete list of historical versions of study NCT00357058 on ClinicalTrials.gov Archive Site|
|Current Secondary Outcome Measures ICMJE||Not Provided|
|Original Secondary Outcome Measures ICMJE||Not Provided|
|Current Other Outcome Measures ICMJE||Not Provided|
|Original Other Outcome Measures ICMJE||Not Provided|
|Brief Title ICMJE||Role of Brain Region Changes in Tactile (Touch) Ability Following Nerve Block|
|Official Title ICMJE||Substrates Mediating Deafferentiation-Induced Enhancement of Tactile Spatial Acuity|
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:
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.
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.
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.
|Study Type ICMJE||Observational|
|Study Design ICMJE||Not Provided|
|Target Follow-Up Duration||Not Provided|
|Sampling Method||Not Provided|
|Study Population||Not Provided|
|Intervention ICMJE||Not Provided|
|Study Group/Cohort (s)||Not Provided|
|Publications *||Allard T, Clark SA, Jenkins WM, Merzenich MM. Reorganization of somatosensory area 3b representations in adult owl monkeys after digital syndactyly. J Neurophysiol. 1991 Sep;66(3):1048-58.|
* Includes publications given by the data provider as well as publications identified by ClinicalTrials.gov Identifier (NCT Number) in Medline.
|Recruitment Status ICMJE||Completed|
|Completion Date||December 2007|
|Primary Completion Date||Not Provided|
|Eligibility Criteria ICMJE||
Normal volunteers who are willing and able to remain relaxed and immobile during active scans, for a period of up to 2 hours.
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.
|Ages||18 Years and older|
|Accepts Healthy Volunteers||No|
|Contacts ICMJE||Contact information is only displayed when the study is recruiting subjects|
|Location Countries ICMJE||United States|
|NCT Number ICMJE||NCT00357058|
|Other Study ID Numbers ICMJE||020079, 02-N-0079|
|Has Data Monitoring Committee||Not Provided|
|Responsible Party||Not Provided|
|Study Sponsor ICMJE||National Institute of Neurological Disorders and Stroke (NINDS)|
|Collaborators ICMJE||Not Provided|
|Investigators ICMJE||Not Provided|
|Information Provided By||National Institutes of Health Clinical Center (CC)|
|Verification Date||December 2007|
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