Name: topographical estimation of visual population receptive fields by fmri
Uploaded: 2015-02-03T14:00:00.000+00:00
Duration: 6 min 2 s
Description: Watch this Scientific Journal Video about Topographical Estimation of Visual Population Receptive Fields by fMRI at JoVE.com

We thank the VISTA software group (Brian Wandell and associates, at Stanford).
S. S. was supported by McNair 2280403105,NEI R01-EY109272, and NEI R01-EY024019 and as HHMI Early Carrer Award. A. P. and G. K. was supported by the Max-Planck Society, G. K. was supported by the PLASTICISE project of the 7th Framework Programme of the European Commission, Contract no. HEATH-F2-2009-223524.

1.数据采集<ol><li>制备刺激协议是有效的如先前在迪穆兰和万德尔1和Lee 等人所述引出一个可靠初级视视觉响应。2。然而，其他公认的范例也适用视具体实验问题有待解决。 </li><li>本栏刺激飘过屏幕顺序地沿着空间8个方向，步长为45度。确保该运动是同步地与扫描框采集（TR〜2秒），以使杆移动一次一个步骤的功能磁共振成像帧开始，并保持在新的位置，直到该帧结束。 </li><li>衡量一个正确的基准信号，没有酒吧刺激1加时代。 <ol><li>定义的图（10至15°半径）在视觉角度在其上的刺激呈现一个字段。目前移动或抖动棋盘图案（方格大小为0.94 x 0.94英寸度2，patte酒吧内的氡更新率= 250毫秒/模式），以引起强烈的视觉反应。 </li><li>输入以下具体参数:8均匀分布的运动方向，条宽等于1.875度，和酒吧将通过每帧（2秒）半条宽。额外的细节可以在Lee 等人的发现。2。 </li><li>产生在屏幕中心上的实验过程中拍摄对象的眼睛注视一个点（0.25〜°）。在一次随意改变现货颜色。 </li></ol></li><li>扫描使用典型回波平面成像（EPI）扫描具有192帧的持续时间（在运动的每个方向上24帧）在MRI扫描器受试者的脑。重复扫描的4-8倍，以增加信噪比。 </li><li>集参数的EPI顺序如下:TR = 2秒，TE = 40毫秒，矩阵尺寸= 64×64，28片，体素大小= 3×3×3mm的3，翻转角= 90°，或者，应用序列以更高的分辨率（ 如克，2×2×2mm的3）或一短TR（ 例如 ，1-1.5秒）仅覆盖视觉皮层2。 </li><li>追踪眼球运动过程中与扫描功能的眼球追踪系统，以确保固定的保持在固定点的1-1.5度。 注意:在此，头部的坐标基于眼球追踪在目镜系统中被使用，但其它合适的眼球追踪系统可以用来代替。 </li><li>指导受试者注视在步骤1.3.2中产生的屏幕中心的位置。为了确保受试者的行了吧，指导他们报告固定点的色彩变化。 </li><li>获得解剖扫描，在1×1×1毫米3分辨率（ 例如 ，T1-MPRAGE; TR = 1900毫秒，TE = 2.26毫秒，TI = 900毫秒，翻转角= 11°，176分区）。 注意:这些解剖扫描将用于分割以及用于内和跨扫描对准功能图像的解剖结构。对于功能之间进行更好的调整人（EPI）的图像和解剖，还获得面内解剖扫描，具有对EPI的分辨率相同，使用T1加权快速扰梯度回波（SPGR）序列1。 </li></ol> 2.数据预处理注意:在此之前推定PRF性能，需要几个典型的fMRI数据前处理步骤，如头部运动校正和功能的卷的解剖扫描对准。在这篇文章中，得到的结果都预处理，估计，分析和表达所使用的开放源码基于MATLAB软件工具箱VISTA LAB可在VISTA软件的网站进行。 http://white.stanford.edu/newlm/index.php/Main_Page。 <ol><li>加载解剖扫描到MATLAB和使用称为createVolAnat功能准备卷解剖。 </li><li>段灰质，白质和CSF使用功能"ItkGray"。 </li><li>通过转换DICOM准备功能的数据（ 即 </e使用一种称为mrInit功能M&gt;，西门子原始MRI文件格式）文件转换成NIFTI（ 即标准的功能性磁共振成像文件格式）文件，并加载数据到VISTA。 </li><li>正确的头部运动和调整功能图像使用rxAlign基于仿射矩阵变换步骤2.1加载的解剖。 </li><li>平均官能运动校正的扫描用于改善信噪比通过点击mrVISTA分析时间序列的平均TSERIES。从平均扫描期间，眼球运动，从固定偏差超过1-1.5度排除。如果从不同的运行信号具有不同的直流漂移，去除直流漂移后平均官能扫描。 </li><li>计算功能扫描和灰质的贴图坐标，并通过选择以下菜单识别功能的扫描相应的灰质体素:mrVISTA窗口打开灰三视图窗口。在灰质像素插值​​分配BOLD信号，选择的选项之一vailable在mrVISTA。 </li></ol> 3.估计PRF地形和参数化建模<ol><li>通过下面的链接下载的代码文件:https://sites.google.com/site/leesangkyun/prf/codes.zip，解压压缩文件并将其放置在本地计算机的首选地点。添加在MATLAB的文件夹的路径。 </li><li>设置通过选择以下菜单用于实验的刺激参数:mrVISTA分析初级视模式设置参数。指定以下参数，如刺激图象，刺激大小，典型的血液动力学功能，功能磁共振成像扫描仪的帧速率。 </li><li>在此之前的PRF的估计，准备初始参数集（ 图1B）。 <ol><li>从代码文件设置的交叉验证集"tprf_set_params.m"。除法时间序列划分成至少两个子集（一组用于测试和训练剩余集）是足够长的条来SWEEP整个刺激的空间。可替代地，如果没有在步骤2.4平均扫描，通过省去一次扫描进行检测，并使用剩余的扫描训练验证扫描。 </li><li>设置一个粗参数集（λ在图1中;λ= [10 -2 10 -1 1 10 1 10 2]）中的"tprf_set_params.m"。然后，树立了良好的规模范围（[0.1 0.3 0.5 0.7 0.9 1 3 5 7 9]）在"tprf_set_params.m"。 注:本方案采用粗集选择导致最高解释方差的λ。然后，程序搜索使用精细尺度范围围绕所选λ的空间，进一步细化λ的产生最高解释方差选择。 </li><li>对于在"tprf_set_params.m"视觉响应的体素设定解释方差的阈值（0.2）。 注意:此阈值被用作用于选择的视觉响应的体素基准。另外，作出投资回报率的非视觉响应区（ 例如 ，通过绘制一个球体为1厘米的非视觉响应脑区域的半径），其中所述阈值可以自动计算。 </li><li>设置一组阈值（[0.3，0.5，0.7]），用于限定PRF中心区域中的归一化地形"tprf_set_params.m"（ 即 ，[0-1]或[-1至1]与历元无杆刺激在步骤1.3.1）。 注意:从设定的阈值的规定的程序选择"最好"的阈值， 也就是说 ，它定义为其中PRF中心模型解释了最大信号方差一个PRF中心区域的阈值。另外，选择不同的设置根据地形特点的阈值。 </li></ol></li><li>执行"tprf_runpRFest.m"计算PRF形貌（ 图1）和适合的2D各向异性高斯。指定在本协议中所描述的所有参数后，和运行代码，得到最终的估计结果。 </li></ol><img alt="图1" src="/files/ftp_upload/51811/51811fig1highres.jpg" width="700" /> 图1:PRF估计处理。 （A）的过程示意图遵循PRF地形估计H（T）:血流动力学响应函数，A（T）:刺激，M:PRF，注册:L2范数正规化（B）的具体步骤PRF地形估计和PRF中心模型。集所需的估计参数中列出的每个步骤。地形和模型的一维节中说明。在"模型拟合"，黑色和红色的曲线代表了地形和0.5，分别为中心的阈值PRF中心模式。蓝色虚线表示的PRF阈值中部地区。

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	<li>Dumoulin, S. O., Wandell, B. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Population+receptive+field+estimates+in+human+visual+cortex.">Population receptive field estimates in human visual cortex.</a> Neuroimage. 39, 647-660 (2008).</li><li>Lee, S., Papanikolaou, A., Logothetis, N. K., Smirnakis, S. M., Keliris, G. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+new+method+for+estimating+population+receptive+field+topography+in+visual+cortex.">A new method for estimating population receptive field topography in visual cortex.</a> Neuroimage. 81, 144-157 (2013).</li><li>Hastie, T., Tibshirani, R., Friedman, J. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> The elements of statistical learning : data mining, inference, and prediction. , (2009).</li><li>Sereno, M. I., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Borders+of+multiple+visual+areas+in+humans+revealed+by+functional+magnetic+resonance+imaging.">Borders of multiple visual areas in humans revealed by functional magnetic resonance imaging.</a> Science. 268, 889-893 (1995).</li><li>Engel, S. A., Glover, G. H., Wandell, B. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Retinotopic+organization+in+human+visual+cortex+and+the+spatial+precision+of+functional+MRI.">Retinotopic organization in human visual cortex and the spatial precision of functional MRI.</a> Cereb Cortex. 7, 181-192 (1997).</li><li>Engel, S. A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=fMRI+of+human+visual+cortex.">fMRI of human visual cortex.</a> Nature. 369, 525 (1994).</li><li>DeYoe, E. A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mapping+striate+and+extrastriate+visual+areas+in+human+cerebral+cortex.">Mapping striate and extrastriate visual areas in human cerebral cortex.</a> Proc Natl Acad Sci U S A. 93, 2382-2386 (1996).</li><li>Greene, C. A., Dumoulin, S. O., Harvey, B. M., Ress, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Measurement+of+population+receptive+fields+in+human+early+visual+cortex+using+back-projection+tomography.">Measurement of population receptive fields in human early visual cortex using back-projection tomography.</a> J Vis. , (2014).</li><li>Zuiderbaan, W., Harvey, B. M., Dumoulin, S. O. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Modeling+center-surround+configurations+in+population+receptive+fields+using+fMRI.">Modeling center-surround configurations in population receptive fields using fMRI.</a> J Vis. , (2012).</li><li>Harvey, B. M., Dumoulin, S. O. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+relationship+between+cortical+magnification+factor+and+population+receptive+field+size+in+human+visual+cortex:+constancies+in+cortical+architecture.">The relationship between cortical magnification factor and population receptive field size in human visual cortex: constancies in cortical architecture.</a> J Neurosci. 31, 13604-13612 (2011).</li><li>Haak, K. V., Cornelissen, F. W., Morland, A. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Population+receptive+field+dynamics+in+human+visual+cortex.">Population receptive field dynamics in human visual cortex.</a> PLoS One. 7, e37686 (2012).</li></ol>

The authors declare that they have no competing financial interests.

本文演示了如何估计在人类视觉皮层以及如何使用它来选择感受野适当的参数化模型可视化人口感受野的地形。对于一个成功的retinotopy，一个适当的刺激方案和有效的分析方法，应选择，和被检者的实验参数（运动和固定）应该被优化。酒吧的刺激依次穿过视野运动是一种有效的刺激范式PRF估计，因为它产生区别于刺激的地点不同的BOLD响应。所提供的方法构建PRF地形。自PRF估计问题通常是根据?...

功能性磁共振成像（fMRI）测量非侵入视皮层中的宏观尺度的功能组织（通常在几毫米的数量级）。早期的功能磁共振成像研究retinotopy用于刺激位置之间的连贯性的措施，引起BOLD反应4-7。这些研究通常没有估计总体感受野大小。以后，迪穆兰和万德尔1提出明确建模的PRF的位置和大小，利用该模型的一个线性函数来预测BOLD反应来克服这种限制的方法。然而，这一开创性方法的一个限制是该参数PRF模型必须选择一个先验，并可能导致错误的PRF估计，如果它原来不恰当。 为了克服参数PRF-模型方法的局限性，新方法最近已开发的。这些方法直接预测到S的BOLD响应timulus通过重构PRF地形。建议由格林和他的同事的方法8重建PRF地形通过背投影BOLD响应个别维刺激空间，建设PRF地形就像一个典型的计算机断层扫描技术的2D刺激的空间。另一方面，我们提出的方法2直接估计2D PRF地形通过使用线性回归和施加一个正则化技术。在该方法中，PRF地形被表示为一组权值被乘以的刺激来估计给定体素的神经元群的响应。那么，最后的血氧水平依赖（BOLD）响应的刺激诱发估计通过卷积神经元群的响应和规范的血流动力学响应函数。为了解决上述下约束线性系统，此外，岭回归正规化用于强制稀疏（ 见图1下文）。正规化技术抑制噪音和伪影，从而使我们的方法，以更有力估计PRF地形。 地形方法不强制PRF形状有一定的参数形状，因此可以发现实际PRF结构。适当的参数化模型然后可以基于该PRF地形选择。例如，该PRF形貌可以用于分离PRF中心和环绕，然后随后的PRF中心建模可通过最大限度地减少环绕抑制在遥远的区域中出现的其他潜在伪影的影响的影响，以及更准确PRF中心。我们最近完成我们的方法，直接几种其他方法之间的定量比较（ 即估计地形之前）适合各向同性高斯1，各向异性高斯和各向同性高斯差到PRF 9。人们发现，在topography为基础的方法优于这些方法相对于PRF中心建模通过实现更高的解释BOLD信号时序的变化。 PRF特性在各个领域的精确估计揭示他们如何覆盖视野，是研究视觉皮层特别是因为它涉及到视觉感知的功能组织重要。性能，如如何与偏心1,10和PRF中心环绕组织9 PRF尺寸变化很好的研究，在人类文学。所提出的方法用于估计PRF地形导致更准确的PRF的参数建模和更可能揭示未知规律，不容易建模的先验在直接参数化模型。这种做法将特别适合学习PRF组织患者视觉通路病变，对他们来说，PRF结构也不一定能够预测先验。下面描述如何估计第ËPR​​F地形以及如何使用地形的PRF中心模式。

<table><tbody><tr><td>MRI scanner</td><td>Siemens/Philips/GE</td><td></td><td></td></tr><tr><td>MATLAB</td><td>The Mathworks, Inc.</td><td></td><td>http://www.mathworks.com&amp;nbsp;</td></tr><tr><td>VISTA software</td><td>VISTA software group</td><td></td><td>http://white.stanford.edu/newlm/index.php/Software</td></tr><tr><td>PsychoToolbox</td><td>PsychoToolbox&amp;nbsp;</td><td></td><td>http://psychtoolbox.org&amp;nbsp;</td></tr><tr><td>Eye Tracker (VisuaStimDigital)</td><td>Resonance Technology Inc</td><td></td><td>http://mrivideo.com/</td></tr></tbody></table>

topographical estimation of visual population receptive fields by fmri

视觉皮层retinotopically组织使得细胞群相邻映射到视场的相邻部件。功能性磁共振成像使我们能够估计基于体素的人口感受域（PRF）， 即 ，视场激活每个体素中的细胞的一部分。之前，直接，PRF估计方法1遭受一定的局限性:1）PRF模型被选择的先验和可能不完全捕获实际的PRF的形状，和2）PRF中心是容易发生的刺激空间的边界附近的错误定位。在这里，一个新的地形PRF估计方法2建议在很大程度上规避这些限制。线性模型被用来通过卷积PRF到视觉刺激与规范的血流动力学响应函数的线性响应预测血氧水平依赖（BOLD）信号。 PRF地形被表示为权重向量，其分量所代表的STR素神经元的总响应ength来刺激呈现在不同的视野位置。由此产生的线性方程组可以解决使用岭回归3 PRF的权重向量，产生PRF地形。一个匹配于所估计的地形是一个PRF，模型然后可以选择事后，由此提高PRF的参数，如PRF-中心位置，PRF方向，大小等的估算值。具有PRF形貌可用也允许的PRF的参数估计，允许各种PRF性质的提取的视觉验证，而不必做出关于PRF结构的先验假设。这种方法有望成为调查的患者的PRF组织与视觉系统的疾病特别有用。

准确的PRF建模需要正确捕捉PRF形状。不知道PRF地形，圆对称模型之前的研究1,9-11使用的选择是合理的选择。这是因为，如果本地初级视组织具有同样的视场的所有方向中，当地居民的反应可以表示为神经元响应一个圆对称的累积总和。然而，我们的观察表明，这不是必须的情况下（ 图2）。因此，观察PRF地形的可用于一个PRF模型选择一个适当的参数函数的关键。这就是PRF地形?...

Watch this Scientific Journal Video about Topographical Estimation of Visual Population Receptive Fields by fMRI at JoVE.com

Topographical Estimation of Visual Population Receptive Fields by fMRI

It is important to obtain unbiased estimates of visual population receptive fields (pRFs) by functional magnetic resonance imaging. We use mild regularization constraints to estimate pRF topography without a-priori assumptions about pRF shape, allowing us to choose specific pRF models post-hoc. This is particularly advantageous in subjects with visual-pathway lesions.

人口视觉感受野由功能磁共振成像地形估计

Visual cortex is retinotopically organized so that neighboring populations of cells map to neighboring parts of the visual field. Functional magnetic ...

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9.2K 次观看.  Baylor College of Medicine. It is important to obtain unbiased estimates of visual population receptive fields (pRFs) by functional magnetic resonance imaging. We use mild regularization constraints to estimate pRF topography without a-priori assumptions about pRF shape, allowing us to choose specific pRF models post-hoc. This is particularly advantageous in subjects with visual-pathway lesions.

视频: Topographical Estimation of Visual Population Receptive Fields by fMRI

Functional Magnetic Resonance Imaging (fMRI) with Auditory Stimulation in Songbirds

The neurobiology of birdsong, as a model for human speech, is a pronounced area of research in behavioral neuroscience. Whereas electrophysiology and molecular approaches allow the investigation of either different stimuli on few neurons, or one stimulus in large parts of the brain, blood oxygenation level dependent (BOLD) functional Magnetic Resonance Imaging (fMRI) allows combining both advantages, i.e. compare the neural activation induced by different stimuli in the entire brain at once. fMRI in songbirds is challenging because of the small size of their brains and because their bones and especially their skull comprise numerous air cavities, inducing important susceptibility artifacts. Gradient-echo (GE) BOLD fMRI has been successfully applied to songbirds 1-5 (for a review, see 6). These studies focused on the primary and secondary auditory brain areas, which are regions free of susceptibility artifacts. However, because processes of interest may occur beyond these regions, whole brain BOLD fMRI is required using an MRI sequence less susceptible to these artifacts. This can be achieved by using spin-echo (SE) BOLD fMRI 7,8 . In this article, we describe how to use this technique in zebra finches (Taeniopygia guttata), which are small songbirds with a bodyweight of 15-25 g extensively studied in behavioral neurosciences of birdsong. The main topic of fMRI studies on songbirds is song perception and song learning. The auditory nature of the stimuli combined with the weak BOLD sensitivity of SE (compared to GE) based fMRI sequences makes the implementation of this technique very challenging.

Functional Magnetic Resonance Imaging fMRI with Auditory Stimulation in Songbirds

This article shows an optimized procedure for imaging of the neural substrates of auditory stimulation in the songbird brain using functional Magnetic Resonance Imaging (fMRI). It describes the preparation of the sound stimuli, the positioning of the subject and the acquisition and subsequent analysis of the fMRI data.

功能磁共振成像（fMRI）技术与听觉刺激鸣禽

The neurobiology of birdsong, as a model for human speech, is a pronounced area of research in behavioral neuroscience. Whereas electrophysiology and ...

科研

行为学

fMRI Validation of fNIRS Measurements During a Naturalistic Task

We present a method to compare brain activity recorded with near-infrared spectroscopy (fNIRS) in a dance video game task to that recorded in a reduced version of the task using fMRI (functional magnetic resonance imaging). Recently, it has been shown that fNIRS can accurately record functional brain activities equivalent to those concurrently recorded with functional magnetic resonance imaging for classic psychophysical tasks and simple finger tapping paradigms. However, an often quoted benefit of fNIRS is that the technique allows for studying neural mechanisms of complex, naturalistic behaviors that are not possible using the constrained environment of fMRI. Our goal was to extend the findings of previous studies that have shown high correlation between concurrently recorded fNIRS and fMRI signals to compare neural recordings obtained in fMRI procedures to those separately obtained in naturalistic fNIRS experiments. Specifically, we developed a modified version of the dance video game Dance Dance Revolution (DDR) to be compatible with both fMRI and fNIRS imaging procedures. In this methodology we explain the modifications to the software and hardware for compatibility with each technique as well as the scanning and calibration procedures used to obtain representative results. The results of the study show a task-related increase in oxyhemoglobin in both modalities and demonstrate that it is possible to replicate the findings of fMRI using fNIRS in a naturalistic task. This technique represents a methodology to compare fMRI imaging paradigms which utilize a reduced-world environment to fNIRS in closer approximation to naturalistic, full-body activities and behaviors. Further development of this technique may apply to neurodegenerative diseases, such as Parkinson&#8217;s disease, late states of dementia, or those with magnetic susceptibility which are contraindicated for fMRI scanning.

We present a method to compare functional brain activity recorded during a naturalistic task using fNIRS with activity recorded during fMRI.

的fNIRS功能磁共振成像测量验证过程中一个自然主义任务

We present a method to compare brain activity recorded with near-infrared spectroscopy (fNIRS) in a dance video game task to that recorded in a reduced ...

High-resolution Functional Magnetic Resonance Imaging Methods for Human Midbrain

Functional MRI (fMRI) is a widely used tool for non-invasively measuring correlates of human brain activity. However, its use has mostly been focused upon measuring activity on the surface of cerebral cortex rather than in subcortical regions such as midbrain and brainstem. Subcortical fMRI must overcome two challenges: spatial resolution and physiological noise. Here we describe an optimized set of techniques developed to perform high-resolution fMRI in human SC, a structure on the dorsal surface of the midbrain; the methods can also be used to image other brainstem and subcortical structures.
High-resolution (1.2 mm voxels) fMRI of the SC requires a non-conventional approach. The desired spatial sampling is obtained using a multi-shot (interleaved) spiral acquisition1. Since, T2* of SC tissue is longer than in cortex, a correspondingly longer echo time (TE ~ 40 msec) is used to maximize functional contrast. To cover the full extent of the SC, 8-10 slices are obtained. For each session a structural anatomy with the same slice prescription as the fMRI is also obtained, which is used to align the functional data to a high-resolution reference volume.
In a separate session, for each subject, we create a high-resolution (0.7 mm sampling) reference volume using a T1-weighted sequence that gives good tissue contrast. In the reference volume, the midbrain region is segmented using the ITK-SNAP software application2. This segmentation is used to create a 3D surface representation of the midbrain that is both smooth and accurate3. The surface vertices and normals are used to create a map of depth from the midbrain surface within the tissue4.
Functional data is transformed into the coordinate system of the segmented reference volume. Depth associations of the voxels enable the averaging of fMRI time series data within specified depth ranges to improve signal quality. Data is rendered on the 3D surface for visualization.
In our lab we use this technique for measuring topographic maps of visual stimulation and covert and overt visual attention within the SC1. As an example, we demonstrate the topographic representation of polar angle to visual stimulation in SC.

This article describes techniques to perform high-resolution functional magnetic resonance imaging with 1.2 mm sampling in human midbrain and subcortical structures using a 3T scanner. Use of these techniques to resolve topographic maps of visual stimulation in the human superior colliculus (SC) is given as an example.

高分辨率人类中脑功能磁共振成像方法

Functional MRI (fMRI) is a widely used tool for non-invasively measuring correlates of human brain activity. However, its use has mostly been focused upon ...

神经科学

Co-analysis of Brain Structure and Function using fMRI and Diffusion-weighted Imaging

The study of complex computational systems is facilitated by network maps, such as circuit diagrams. Such mapping is particularly informative when studying the brain, as the functional role that a brain area fulfills may be largely defined by its connections to other brain areas. In this report, we describe a novel, non-invasive approach for relating brain structure and function using magnetic resonance imaging (MRI). This approach, a combination of structural imaging of long-range fiber connections and functional imaging data, is illustrated in two distinct cognitive domains, visual attention and face perception. Structural imaging is performed with diffusion-weighted imaging (DWI) and fiber tractography, which track the diffusion of water molecules along white-matter fiber tracts in the brain (Figure 1). By visualizing these fiber tracts, we are able to investigate the long-range connective architecture of the brain. The results compare favorably with one of the most widely-used techniques in DWI, diffusion tensor imaging (DTI). DTI is unable to resolve complex configurations of fiber tracts, limiting its utility for constructing detailed, anatomically-informed models of brain function. In contrast, our analyses reproduce known neuroanatomy with precision and accuracy. This advantage is partly due to data acquisition procedures: while many DTI protocols measure diffusion in a small number of directions (e.g., 6 or 12), we employ a diffusion spectrum imaging (DSI)1, 2 protocol which assesses diffusion in 257 directions and at a range of magnetic gradient strengths. Moreover, DSI data allow us to use more sophisticated methods for reconstructing acquired data. In two experiments (visual attention and face perception), tractography reveals that co-active areas of the human brain are anatomically connected, supporting extant hypotheses that they form functional networks. DWI allows us to create a "circuit diagram" and reproduce it on an individual-subject basis, for the purpose of monitoring task-relevant brain activity in networks of interest.

We describe a novel approach for simultaneous analysis of brain function and structure using magnetic resonance imaging (MRI). We assess brain structure with high-resolution diffusion-weighted imaging and white-matter fiber tractography. Unlike standard structural MRI, these techniques allow us to directly relate anatomical connectivity to functional properties of brain networks.

使用功能磁共振成像和弥散加权成像脑结构与功能分析

The study of complex computational systems is facilitated by network maps, such as circuit diagrams. Such mapping is particularly informative when ...

Detecting Pre-Stimulus Source-Level Effects on Object Perception with Magnetoencephalography

Pre-stimulus oscillatory brain activity influences upcoming perception. The characteristics of this pre-stimulus activity can predict whether a near-threshold stimulus will be perceived or not perceived, but can they also predict which one of two competing stimuli with different perceptual contents is perceived? Ambiguous visual stimuli, which can be seen in one of two possible ways at a time, are ideally suited to investigate this question. Magnetoencephalography (MEG) is a neurophysiological measurement technique that records magnetic signals emitted as a result of brain activity. The millisecond temporal resolution of MEG allows for a characterization of oscillatory brain states from as little as 1 second of recorded data. Presenting an empty screen around 1 second prior to the ambiguous stimulus onset therefore provides a time window in which one can investigate whether pre-stimulus oscillatory activity biases the content of upcoming perception, as indicated by participants&#39;&#160;reports. The spatial resolution of MEG is not excellent, but sufficient to localise sources of brain activity at the centimetre scale. Source reconstruction of MEG activity then allows for testing hypotheses about the oscillatory activity of specific regions of interest, as well as the time- and frequency-resolved connectivity between regions of interest. The described protocol enables a better understanding of the influence of spontaneous, ongoing brain activity on visual perception.

This article describes how to set up an experiment that allows detecting pre-stimulus source-level influences on object perception using magnetoencephalography (MEG). It covers stimulus material, experimental design, MEG recording, and data analysis.

利用磁脑学检测刺激前源级对物体感知的影响

Pre-stimulus oscillatory brain activity influences upcoming perception. The characteristics of this pre-stimulus activity can predict whether a ...

Mapping Regional Homogeneity and Functional Connectivity of the Visual Cortex in Resting-State fMRI

A combined regional homogeneity (ReHo) and functional connectivity (FC) method, a type of noninvasive functional magnetic resonance imaging (fMRI) method, has been used to evaluate synchronous neuronal activity changes in retinitis pigmentosa (RP). The purpose of this study is to describe our method for analysis of intra- and interregional synchronizations of changes in neuronal activity in RP patients. The advantages of the combined ReHo and FC method are that it is both noninvasive and sufficiently sensitive to investigate changes in cerebral synchronous neuronal activity changes in vivo. Here, 16 RP patients and 14 healthy controls closely matched in age, sex, and education underwent resting-state fMRI scans. Two sample t-tests were conducted to compare ReHo and FC across groups. Our results showed that visual network disconnection and reorganization of the retino-thalamocortical pathway and dorsal visual stream occurred in the RP patients. Here, we describe the details of this method, its use, and the impact of its key parameters in a step-by-step manner.

We present a protocol for analyzing functional magnetic resonance imaging data to investigate spontaneous neural activity alterations in retinitis pigmentosa patient using a combined regional homogeneity and functional connectivity method.

A combined regional homogeneity (ReHo) and functional connectivity (FC) method, a type of noninvasive functional magnetic resonance imaging (fMRI) method, ...

Simultaneous Data Collection of fMRI and fNIRS Measurements Using a Whole-Head Optode Array and Short-Distance Channels

Functional near-infrared spectroscopy (fNIRS) is a portable neuroimaging methodology, more robust to motion and more cost-effective than functional magnetic resonance imaging (fMRI), which makes it highly suitable for conducting naturalistic studies of brain function and for use with developmental and clinical populations. Both fNIRS and fMRI methodologies detect changes in cerebral blood oxygenation during functional brain activation, and prior studies have shown high spatial and temporal correspondence between the two signals. There is, however, no quantitative comparison of the two signals collected simultaneously from the same subjects with whole-head fNIRS coverage. This comparison is necessary to comprehensively validate area-level activations and functional connectivity against the fMRI gold standard, which in turn has the potential to facilitate comparisons of the two signals across the lifespan. We address this gap by describing a protocol for simultaneous data collection of fMRI&#160;and fNIRS signals that: i) provides whole-head fNIRS coverage; ii) includes short-distance measurements for regression of the non-cortical, systemic physiological signal; and iii) implements two different methods for optode-to-scalp co-registration of fNIRS measurements. fMRI and fNIRS data from three subjects are presented, and recommendations for adapting the protocol to test developmental and clinical populations are discussed. The current setup with adults allows scanning sessions for an average of approximately 40 min, which includes both functional and structural scans. The protocol outlines the steps required to adapt the fNIRS equipment for use in the magnetic resonance (MR) environment, provides recommendations for both data recording and optode-to-scalp co-registration, and discusses potential modifications of the protocol to fit the specifics of the available MR-safe fNIRS system. Representative subject-specific responses from a flashing-checkerboard task illustrate the feasibility of the protocol to measure whole-head fNIRS signals in the MR environment. This protocol will be particularly relevant for researchers interested in validating fNIRS signals against fMRI across the lifespan.

We present a method for simultaneously collecting fMRI and fNIRS signals from the same subjects with whole-head fNIRS coverage. The protocol has been tested with three young adults and can be adapted for data collection for developmental studies and clinical populations.

使用全头光电阵列和短距离通道同时收集 fMRI 和 fNIRS 测量数据

Functional near-infrared spectroscopy (fNIRS) is a portable neuroimaging methodology, more robust to motion and more cost-effective than functional ...

推进视觉皮层映射以增强对视力障碍的评估

Functional Magnetic Resonance Imaging (fMRI) of the Visual Cortex with Wide-View Retinotopic Stimulation

High-resolution retinotopic blood oxygenation level-dependent (BOLD) functional magnetic resonance imaging (fMRI) with a wide-view presentation can be used to functionally map the peripheral and central visual cortex. This method for measuring functional changes of the visual brain allows for functional mapping of the occipital lobe, stimulating &gt;100&#176; (&plusmn;50&#176;) or more of the visual field, compared to standard fMRI visual presentation setups which usually cover &lt;30&#176; of the visual field. A simple wide-view stimulation system for BOLD fMRI can be set up using common MR-compatible projectors by placing a large mirror or screen close to the subject's face and using only the posterior half of a standard head coil to provide a wide-viewing angle without obstructing their vision. The wide-view retinotopic fMRI map can then be imaged using various retinotopic stimulation paradigms, and the data can be analyzed to determine the functional activity of visual cortical regions corresponding to central and peripheral vision. This method provides a practical, easy-to-implement visual presentation system that can be used to evaluate changes in the peripheral and central visual cortex due to eye diseases such as glaucoma and the vision loss that may accompany them.

作者聚焦:通过宽视角 fMRI 映射洞察视觉皮层研究 

We have developed techniques for mapping the visual cortex function utilizing more of the visual field than is commonly used. This approach has the potential to enhance the evaluation of vision disorders and eye diseases.

具有宽视网膜刺激的视觉皮层功能性磁共振成像 （fMRI）

High-resolution retinotopic blood oxygenation level-dependent (BOLD) functional magnetic resonance imaging (fMRI) with a wide-view presentation can be ...

人口视觉感受野由功能磁共振成像地形估计

摘要

探索更多视频

此视频中的章节

功能磁共振成像（fMRI）技术与听觉刺激鸣禽

的fNIRS功能磁共振成像测量验证过程中一个自然主义任务

高分辨率人类中脑功能磁共振成像方法

使用功能磁共振成像和弥散加权成像脑结构与功能分析

利用磁脑学检测刺激前源级对物体感知的影响

Mapping Regional Homogeneity and Functional Connectivity of the Visual Cortex in Resting-State fMRI

使用全头光电阵列和短距离通道同时收集 fMRI 和 fNIRS 测量数据

具有宽视网膜刺激的视觉皮层功能性磁共振成像（fMRI）

具有宽视网膜刺激的视觉皮层功能性磁共振成像（fMRI）

具有宽视网膜刺激的视觉皮层功能性磁共振成像（fMRI）

人口视觉感受野由功能磁共振成像地形估计

摘要

探索更多视频

此视频中的章节

功能磁共振成像（fMRI）技术与听觉刺激鸣禽

的fNIRS功能磁共振成像测量验证过程中一个自然主义任务

高分辨率人类中脑功能磁共振成像方法

使用功能磁共振成像和弥散加权成像脑结构与功能分析

利用磁脑学检测刺激前源级对物体感知的影响

Mapping Regional Homogeneity and Functional Connectivity of the Visual Cortex in Resting-State fMRI

使用全头光电阵列和短距离通道同时收集 fMRI 和 fNIRS 测量数据

具有宽视网膜刺激的视觉皮层功能性磁共振成像 （fMRI）

具有宽视网膜刺激的视觉皮层功能性磁共振成像 （fMRI）

具有宽视网膜刺激的视觉皮层功能性磁共振成像 （fMRI）

具有宽视网膜刺激的视觉皮层功能性磁共振成像（fMRI）

具有宽视网膜刺激的视觉皮层功能性磁共振成像（fMRI）

具有宽视网膜刺激的视觉皮层功能性磁共振成像（fMRI）