Brain Stimulation and Vision Testing
|First Received Date ICMJE||June 8, 2012|
|Last Updated Date||August 16, 2014|
|Start Date ICMJE||May 2012|
|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 NCT01617408 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||Brain Stimulation and Vision Testing|
|Official Title ICMJE||TMS Investigations of the Human Visual System|
- The brain has two systems for recognizing objects. One system recognizes what an object is, and the other system recognizes where the object is located. However, there is much about how the brain handles and interprets the information from these two systems that is still unclear. Researchers want to study the parts of the brain that are involved in how vision is processed. They will use magnetic resonance imaging (MRI) and transcranial magnetic stimulation (TMS) on the brain. MRI measures what parts of the brain become more active when tasks are performed. TMS uses magnetic pulses to temporarily change the activity in parts of the brain.
- To better understand how people visually recognize different types of objects.
- Healthy volunteers between 18 and 50 years of age.
An influential model of cortical organization proposes that the primate visual system is divided into two functionally distinct pathways (Ungerleider & Mishkin, 1982). The ventral or what visual pathway, which projects from occipital cortex into the ventral temporal cortex, is principally used for object recognition and identification. The dorsal or where pathway, which projects from occipital cortex into the parietal cortex, is principally used for locating the position of objects in the visual field and for action planning (Milner & Goodale, 1995; Kravitz et al., 2011). In the proposed series of experiments we will investigate how neural representations in the ventral and dorsal pathways contribute to a range of cognitive tasks including object and scene recognition, attentional selection and face processing. These experiments will principally use transcranial magnetic stimulation (TMS) in combination with functional magnetic resonance imaging (fMRI).
TMS provides a unique experimental tool for studies of human cognitive function because it can be used to transiently and safely disrupt the neural processing in a targeted cortical region while subjects perform concurrent behavioral tasks that depend on the operations of that region. Furthermore TMS can be combined with neuroimaging techniques such as fMRI to examine the remote effects of the induced neural disruption in other task-dependent regions distributed across cortex. We plan to use TMS to address unanswered questions concerning the functioning of the distributed neural networks for different categories of object recognition and in the attention network of the human brain.
We plan to test 240 neurologically normal subjects aged between 18 and 50 years old. Subjects will also take part in an fMRI experiment prior to any subsequent TMS experiments in order to localize the stimulation sites of interest.
The aim of the proposed series of experiments is to examine the effects of the TMS induced neural disruption on behavioral task performance and the neural correlates of the impaired performance as measured with fMRI. Broadly these experiments can be divided into studies that use online and offline TMS. In on-line experiments, TMS will be applied during behavioral tasks. In off-line experiments, theta burst stimulation (TBS) will be delivered before the experimental task and off-line experiments may combine TBS with fMRI.
|Study Type ICMJE||Observational|
|Study Design ICMJE||Time Perspective: Prospective|
|Target Follow-Up Duration||Not Provided|
|Sampling Method||Not Provided|
|Study Population||Not Provided|
|Intervention ICMJE||Not Provided|
|Study Group/Cohort (s)||Not Provided|
* Includes publications given by the data provider as well as publications identified by ClinicalTrials.gov Identifier (NCT Number) in Medline.
|Recruitment Status ICMJE||Recruiting|
|Estimated Enrollment ICMJE||300|
|Completion Date||Not Provided|
|Primary Completion Date||Not Provided|
|Eligibility Criteria ICMJE||
Ages 18-50 years (inclusive)
Individuals with conditions that could pose a risk relating to the safety of the MRI procedure, the TMS procedure or the combined TBS and fMRI procedure will be excluded from the protocol such as:
|Ages||18 Years to 50 Years|
|Accepts Healthy Volunteers||Yes|
|Location Countries ICMJE||United States|
|NCT Number ICMJE||NCT01617408|
|Other Study ID Numbers ICMJE||120128, 12-M-0128|
|Has Data Monitoring Committee||Not Provided|
|Responsible Party||Not Provided|
|Study Sponsor ICMJE||National Institute of Mental Health (NIMH)|
|Collaborators ICMJE||Not Provided|
|Information Provided By||National Institutes of Health Clinical Center (CC)|
|Verification Date||February 2014|
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