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Use of Transcranial Magnetic Stimulation (TMS) and Magnetic Resonance Imaging (MRI) to Study Visual Attention Clinical Trials References presented on Clinical Trials Search is not intended to be a substitute for proven healthcare advice, trips or professional assistance by using a real medical. We aren't mDs. Always confer with your physician about Use of Transcranial Magnetic Stimulation (TMS) and Magnetic Resonance Imaging (MRI) to Study Visual Attention conditions. Clinical Trials Search.org is a website devoted to listing clinical research studies in human subjects. Use of Transcranial Magnetic Stimulation (TMS) and Magnetic Resonance Imaging (MRI) to Study Visual Attention Clinical research trials and Use of Transcranial Magnetic Stimulation (TMS) and Magnetic Resonance Imaging (MRI) to Study Visual Attention medical trials take place in hundreds of localities across the U.S.. A clinical trial or clinical study is a research project with human volunteer subjects. Clinical drug trials and pharmaceutical clinical trials usually evaluate the effectualness of new does drugs. The purpose of the studies / projects is to solve specific human health questions. Clinical trials are a popular way for physicians, government agencies, and private sector companies to discover treatments for all sorts of conditions, such as Use of Transcranial Magnetic Stimulation (TMS) and Magnetic Resonance Imaging (MRI) to Study Visual Attention. Use of Transcranial Magnetic Stimulation (TMS) and Magnetic Resonance Imaging (MRI) to Study Visual Attention Clinical Trials and other clinical trials permit volunteers to access healthcare treatment choices before they are available to the general public. Some times the subjects recieve professional assistance for without cost, and every now and again they are compensated for their time. Sometimes there is a cost for a Use of Transcranial Magnetic Stimulation (TMS) and Magnetic Resonance Imaging (MRI) to Study Visual Attention clinical trial. Subjects often receive the most expert healthcare possible for their Use of Transcranial Magnetic Stimulation (TMS) and Magnetic Resonance Imaging (MRI) to Study Visual Attention condition. Risks are a reality, nevertheless, and could include additional or frequent dr. calls, healthcare dangers (perhaps life-jeopardising), and/or the treatment being ineffective. Trials are federally governed with stern guidelines to protect clinical trials subjects.
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Home > "U" Clinical Trials Conditions > Use of Transcranial Magnetic Stimulation (TMS) and Magnetic Resonance Imaging (MRI) to Study Visual Attention  Use of Transcranial Magnetic Stimulation (TMS) and Magnetic Resonance Imaging (MRI) to Study Visual Attention
Use of Transcranial Magnetic Stimulation (TMS) and Magnetic Resonance Imaging (MRI) to Study Visual Attention
For Condition: Healthy
Status: Recruiting
Sponsor(s): National Institute of Mental Health (NIMH) ,
Synopsis: The purpose of this study is to learn more about how the brain allows people to focus on important objects and filter out unimportant ones when looking at visual images. Our senses provide us with a vast amount of information at any given moment in time. For example, visual scenes contain many different objects that cannot be processed simultaneously because of the limited processing capacity of the brain's visual system. Evidence suggests that a a network of brain regions selects relevant information and filters out irrelevant information when people view cluttered visual scenes. This study will use transcranial magnetic stimulation (TMS) and functional magnetic resonance imaging (fMRI) to determine how the different brain regions involved in attentional control and filtering interact. Participants in this study will undergo computer tests, an MRI scan, and TMS. During the MRI, participants will look at pictures and count objects appearing on a screen. During the TMS, participants will perform a computer test. Participants' ability to pay attention will be tested with and without TMS. Participants may be asked to return for additional tests in the future.
Details: Our senses provide us with a vast amount of information at any given moment in time. For example, visual scenes contain many different objects that cannot all be processed simultaneously because of the limited processing capacity of the visual system. Therefore, attentional mechanisms are required to select relevant objects and filter out irrelevant ones. There is converging evidence from single-cell recording and lesion studies in monkeys and functional brain imaging studies in humans that irrelevant information from cluttered visual scenes is filtered out in extrastriate visual cortex. Functional brain imaging studies also suggest that these attentional filter mechanisms are mediated by top-down feedback signals arising in higher-order areas in frontal and parietal cortex. However, it is not clear these studies whether these frontal and parietal brain regions are functionally significant in attentional control of behavior. Repetitive transcranial magnetic stimulation (rTMS) applied over a particular cortical region can interfere with cognitive processing in that region, thereby creating a virtual disruption in the intact human cerebral cortex. Hence, this tool can be used to determine if a brain region is functionally involved in the performance of a given cognitive function. In the proposed study, we wish to use rTMS to test the hypothesis that attentional filter mechanisms operating in extrastriate cortex are under "top-down" control by regions in the superior parietal lobule. Our approach will use a combination of rTMS and functional magnetic resonance imaging (fMRI). First, subjects will participate in an fMRI experiment designed to localize the regions within the SPL that are involved with attentional processing for each subject. Second, rTMS will be used to create transient virtual disruptions in the superior parietal lobule (SPL) of normal volunteers while they perform a task requiring spatial attention. We hypothesize that, when rTMS is used to interfere with attentional processing in the SPL, subjects will show impaired performance in a task that requires them to filter out irrelevant visual information. In contrast, performance during rTMS should not suffer in a control task in which no irrelevant information needs to be filtered out.
Eligibility:
Study Type: Observational, Natural History
Minimum Age/Maximum Age: /
Genders: Both
Protocol Entry Criteria: INCLUSION CRITERIA: Subjects must be healthy, right-handed and between the ages of 20 - 40. Subjects must have normal or corrected-to-normal vision. EXCLUSION CRITERIA Pregnant women will be excluded. Subjects with a personal or family history of seizures will be excluded. Subjects with a personal history or family history of neurologic disease, ocular foreign body, increased intracranial pressure, open head injury or significant closed head injurywill be excluded. Subjects with cochlear implants, implanted brain stimulators, aneurysm clip or other metal in the head (except mouth) will be excluded. Subjects taking tricyclic anti-depressants, neuroleptic agents or other drugs that lower the seizure threshold will be excluded. Subjects with a history of illicit drug use or who are abusing or withdrawing from alcohol abuse will be excluded. Subjects with a history of a major psychiatric disorder will be excluded. Subjects with implanted medication pumps, pacemakers, intracardiac lines or significant heart disease will be excluded.
Total Enrollment: 30
Location and Contact Information:
National Institute of Mental Health (NIMH) *Recruiting*
Bethesda, Maryland, 20892
United States
Recruiting Patient and Public Liaison Office 1-800-411-1222
Additional Information:
Study ID Numbers: 000177; 00-M-0177
Study Start Date: September 14, 2000
Record last reviewed: September 25, 2003
Additional information available at: clinicaltrials.gov
Clinicaltrials.gov Reference link: NCT00006285
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Use of Transcranial Magnetic Stimulation (TMS) and Magnetic Resonance Imaging (MRI) to Study Visual Attention
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