TMS Investigations of the Human Visual System
试验速览
- 阶段
- 不适用
- 状态
- 招募中
- 入组人数
- 665
- 试验地点
- 1
- 主要终点
- Online behavioral TMS experiments: performance accuracy, sensitivity (d') and reaction time (RT); Offline fMRI TBS experiments: task performance as well as reduced neuronal activity
研究概览
简要总结
Background:
-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) or transcranial electrical stimulation (tES) 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. tES uses electrical current to temporarily change brain function.
Objectives:
-To better understand how people visually recognize different types of objects.
Eligibility:
-Healthy volunteers between 18 and 50 years of age, who only speak English.
Design:
- This study includes many different experiments on vision. Each experiment may combine visual tasks, MRI scans, and TMS or tES. Participants may be asked to have several different tests. Each test will require a separate visit to the National Institutes of Health.
- Participants will be screened with a physical exam and medical history. They will have a baseline brain scan at the first visit.
- Participants may do visual tasks alone, with MRI only, with TMS or tES only, or with MRI and TMS or tES combined. For the visual tasks, they will look at pictures of objects on a computer screen. Sometimes the images will appear very briefly (less than one-tenth of a second). Sometimes they will appear for up to 5 seconds. These images will be of things like faces, bodies, tools, and scenes. Participants will be asked to respond in different ways to the pictures. They may respond by typing on a computer keyboard or by pressing a button. Participants will have time to practice the tasks before the experiment.
- Participants will remain on the study for up to 3 years.
详细描述
Objective
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. 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) or transcranial electrical stimulation (tES) in combination with functional magnetic resonance imaging (fMRI).
TMS and tES provide unique experimental tools for studies of human cognitive function because they can be used to transiently and safely disrupt or enhance the neural processing in a targeted cortical region while subjects perform concurrent behavioral tasks that depend on the operations of that region. Furthermore TMS and tES 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 and tES 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.
Study Population
We plan to test 665 neurologically normal subjects aged between 18 and 50 years old. Subjects will also take part in an fMRI experiment prior to any subsequent TMS or tES experiments in order to localize the stimulation sites of interest.
研究设计
- 研究类型
- Observational
- 观察模型
- Cohort
- 时间视角
- Cross Sectional
入排标准
- 年龄范围
- 18 Years 至 50 Years（Adult）
- 性别
- All
- 接受健康志愿者
- 是
入选标准
- •INCLUSION CRITERIA:
- •Ages 18-50 years (inclusive)
- •Able to read and write in English to guarantee understanding of all written and spoken instructions, which are in English
排除标准
- •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:
- •Those with ferromagnetic metal in the cranial cavity or eye, e.g. aneurysm clip, implanted neural stimulator, cochlear implant, ocular foreign body.
- •Those with an abnormality on a structural MRI.
- •Those with an implanted cardiac pacemaker or auto-defibrillator
- •Those with an insulin pump.
- •Those with an irremovable body piercing
- •Pregnant women
- •Those with a visual impairment that will prevent them from performing the task
- •Those without consent capacity will not be enrolled
- •Those who do not understand the study instructions
- •Those with a history of neurological problems. Neurological problems include, but are not limited to; family history of epilepsy, history of seizures and recurrent migraines.
- •Those using medicines that can lower the seizure threshold. These can include but are not limited to; imipramine, amitriptyline, doxepine, nortriptyline, maprotiline, chlorpromazine, clozapine, foscarnet, ganciclovir, ritonavir, amphetamines.
- •Those with a visual impairment that will prevent them from performing the task
- •Those who have a significant psychiatric illness or have a history of psychiatric illness.
- •NIMH staff/employees/family members
研究组 & 干预措施
1
Neurologically normal subjects aged 18 to 50 years old
结局指标
主要结局
Online behavioral TMS experiments: performance accuracy, sensitivity (d') and reaction time (RT); Offline fMRI TBS experiments: task performance as well as reduced neuronal activity
时间窗: Ongoing
a. Behavioral TMS or tES experiments will measure the speed of a key press to indicate the correct answer and performance accuracy on the task. b. Offline TMS that combine TBS or tES with fMRI will measure changes in BOLD activation in the targeted region as well as in connected cortical areas identified with an independent localizer.
次要结局
未报告次要终点