Employing Magnetic Vestibular Stimulation (MVS) during Functional Imaging

 描述(申请人提供)：功能磁共振成像(FMRI)被广泛用于研究具有高空间分辨率的大脑激活。最近，人类研究表明，fMRI所需的强静态磁场附带地产生磁前庭刺激(MVS)。这些研究表明，MVS：1)由静电场诱发，2)不需要对象移动，3)不依赖于磁场变化(例如，分贝/dt)。这些实验结果表明，磁前庭刺激(MVS)可能会影响大量的fMRI研究，包括静息状态的脑成像，因为MVS产生的前庭反应会随着内耳相对于磁场的方向而变化。给定 前庭刺激的普遍影响-包括对视觉处理、心血管调节、平衡和运动病的影响-MVS可能会潜在地污染广泛的成像研究。为了解决这些问题，我们建议制定一项程序，将MVS的影响降至最低(目标1)。此外，一旦我们能够最大限度地减少MVS的影响，我们也将选择在需要的时候使用MVS(目标2)。更具体地说，我们在目标1中的目标是开发一种程序，通过测量7T磁铁中的知觉和眼球震颤来最大限度地减少MVS的影响，从而为每个受试者找到一个没有可察觉和最小可测量MVS影响的头部位置范围。为了最大限度地减少外周前庭解剖变异的影响，我们还建议对前庭外周的大体解剖(如半规管方向)进行成像。为了证明MVS对静息状态激活的影响，并证明我们可以将其影响降至最低，功能成像将在头部倾斜到两个位置之一的情况下进行-一个位置可以消除MVS引起的知觉错觉并最大限度地减少眼球震颤，另一个位置会同时产生知觉错觉和眼球震颤。在确定了如何最大限度地减少目标1中由于静磁场引起的MVS之后，我们建议在目标2中使用由静磁场诱发的MVS来研究为什么前庭偏头痛(VM)患者的fMRI激活与正常不同--一种伴随前庭刺激异常处理的疾病。

 DESCRIPTION (provided by applicant): Functional magnetic resonance imaging (fMRI) is widely used to study brain activation with high spatial resolution. Recently, human studies have shown that the strong static magnetic field required for fMRI incidentally yields magnetic vestibular stimulation (MVS). These studies show that MVS: 1) is evoked by the static field, 2) does not require subject movement, and 3) does not depend upon magnetic field changes (e.g., dB/dt). These empirical findings suggest that magnetic vestibular stimulation (MVS) could affect a large number of fMRI studies, including resting state brain imaging, since MVS yields vestibular responses that vary with inner ear orientation relative to the magnetic field. Given the pervasive influence of vestibular stimuli - including influences on visual processing, cardiovascular regulation, equilibrium, and motion sickness - MVS could potentially contaminate a broad range of imaging studies. To address these concerns, we propose to develop a procedure to minimize the influences of MVS (Aim 1). Furthermore, once we can minimize the influences of MVS, we will also choose to employ MVS when desired (Aim 2). More specifically, our goal in Aim 1 is to develop a procedure to minimize the influence of MVS by measuring perception and nystagmus in a 7T magnet to find a range of head positions for each subject that yield no perceptible and minimal measurable MVS effects. To minimize the influence of variations in peripheral vestibular anatomy, we also propose to image the gross anatomy (e.g., semicircular canal orientation) of the vestibular periphery. To demonstrate that MVS impacts resting state activation and to demonstrate that we can minimize its influence, functional imaging will be performed with the head tilted into one of two positions - a position found to eliminate MVS-evoked perceptual illusions and minimize nystagmus and a second position that yields both perceptual illusions and nystagmus. After determining how to minimize MVS due to the static magnetic field in Aim 1, we propose to employ MVS evoked by the static magnetic field in Aim 2 to investigate why fMRI activation differs from normal for patients suffering from vestibular migraine (VM) - a disorder accompanied by abnormal processing of vestibular stimuli.