基于这种材料后，根据批准的BCS 1063774由国家科学基金会支持的工作。

1。极角地形刺激和心理物理学为了获得一个极角在SC retinotopic地图的，我们使用一个移动的小圆点为刺激90°楔形（2-9°的可视角度，偏心率平均点速度4°/秒）（ 图1）。据了解，在SC的活动是由申请隐蔽关注5增强，因此，我们在我们的范例中使用注意的任务，以增加可用的信号。上每2秒试验，受试者被指示隐蔽地参加到整个楔形和执行速度的歧视任务，同时保持固定。楔分为2×3点的部门之一，每次试验中，随机选择移动慢或比所有其他点更快的虚拟部门。每次试验后，楔固定旋转30°左右，这样的刺激旋转24秒内完全。每次运行由9.5旋转的刺激（228秒），实验课程包括16-18运行。 为了维持这个任务上的表现主题的整个每次运行的时间，任务的难度调整使用两个随机交错的两个，一个上下楼梯。每两个连续的正确试验后减少8％的速度上的差异，并为每个不正确的审判，其差额将增加8％。 扫描之前，所有科目的练习以外的扫描仪的视觉任务，直到他们达到了性能稳定的水平，这需要3-4个20分钟的时间练习。典型的歧视阈值是在1°-1.5°/秒范围内。 2。主题的制备<ol><li>主题元首安全垫，以尽量减少头部运动之前，内孔扫描器定位。在这些空间分辨率高，功能磁共振成像是特别敏感，运动伪影，使头部的稳定是至关重要的。 </li><li>科目给出了核磁共振compatib乐一方面按钮垫和指示，按哪个按钮来表明自己的判断点速度。 </li></ol> 3。本地化和处方的SC <ol><li>人类SC是一个小，但不同的结构，〜9毫米直径，位于脑的屋顶上。当使用功能​​性核磁共振片的小数量，多航向成像系列都需要精确定位。我们沿矢状轴，冠状面，这些系列。 </li><li>然后，我们使用这些的航向图像精确规定的SC 8-10连续切片，厚1.2毫米，现场的视角（FOV），170毫米，斜，准轴向平面。 </li><li>得到了一次事先收集和一次后功能数据使用一个三维（3D）RF-宠坏草（SPGR）序列（15°翻转角，1.2毫米像素）高分辨率下，T 1加权结构图像。这些图像作为参考对齐fMRI数据，高分辨率的STRuctural参考量在一个单独的会议，我们稍后介绍。 </li></ol> 4。功能磁共振成像参数所有成像进行了GE Signa的HD12 3T磁共振扫描器使用GE提供8通道头部线圈。激励是6.4毫秒窗口SINC脉冲应用，使用扫描仪体线圈。 为了获得1.2毫米采样人的资深大律师，我们用了三杆螺旋轨迹收购6,7。三枪都需要有以下几个原因。特别是，单次收购为我们的扫描仪和视野需要77毫秒，时间过长实际。结合多个镜头校正后减去初始值和相位的线性趋势。 TE是估计从收购前两卷的字段映射在第一帧上增加2毫秒，这张地图是用于线性校正。 〜20信噪比重建图像。在SC的时间功率谱通常像素显示的结构与生理噪音小，使用3次采集的频率比较高，心脏脉搏和呼吸的影响，一个强大的过滤效果。其他的降噪技术，在这种高分辨率的情况下的问题。例如，追溯如RETROICOR 6的校正方法并不适用于多拍数据，和心脏门控引入噪声和干扰T 1 的平衡相关的神器。 回波时间，T E = 40毫秒，长于通常在皮层（30毫秒），因为我们衡量一个相对较长的资深大律师组织在T 2 *（60毫秒），比灰质（〜45毫秒）观察。 采集带宽是有限的，以62.5千赫，以减少峰值梯度电流，导致我们的扫描仪上的不必要的加热。我们选择TR = 1秒，所以三枪量收购，每3秒。 5。结构的MRI和三维建模每个科目在一个单一的独立的会话，我们获得了高分辨率（0.7毫米采样）的参考量，使用的 T 1加权序列提供了良好的组织对比度（三维梯度回波，15°翻转角，准备反演与 T = 450毫秒，2激发，28分钟的时间，0.7毫米的像素）。 在此参考量，我们段组织中脑，脑干和丘脑使用ITK的SNAP的应用2提供的自动和手动技术相结合（ 图2A）的部分。特别是，我们在使用自动分割工具，用户的种子在每个脑干多点，然后软件会自动扩展对比度和强度标准定义的区域内，制约了种子点周围的分割。这种自动分割，然后调整ED，如果有必要，使用手册，“漆像”像素工具。 脑脊液组织的SC接口插使用等密度面镶嵌的分割，并细化到这个初始的表面减少锯齿假象（ 图2，B和D）使用变变形表面算法3。这表面提供了顶点和向外法线向量作为参考层计算（如下所述）以及可视化功能数据的一种手段。 6。图像分析分析fMRI数据，我们使用的mrVista软件包（在下载的可用<a href="http://white.stanford.edu/mrvista.php" target="_blank">http://white.stanford.edu/mrvista.php）</a>以及对在实验室mrVista框架开发工具。在接下来的几个步骤中，我们使用标准mrVista包工具： <ol><li>初始化在mrVista会议，选择的选择空间正常化平均数据的力度，以减少线圈的不均匀性的影响。正常化使用同态的方法，即除以添加剂量估计噪声的强大校正时间平均图像强度低通滤波版本。避免瞬态议员平衡和血流动力学的影响，上半年周期的图像（12秒）被丢弃。 </li><li>纠正内经营的议案。运动估计从卷的时间序列。然而，由于相对较低的图像信号信噪比（SNR）的，我们首先进行5样本棚车平滑后的时间序列。每卷，然后注册到过去的5个样本的平均水平。注意，平滑仅用于估计的议案，和实际数据不平滑。 </li><li>形成的时间平均每次运行的议案，校正后的图像数据，并使用这些平均纠正运行之间的议案USI纳克作为参考上次运行。 </li><li>执行片定时校正。我们使用顺序片收购，因此将执行时序修正后的议案，修正错误，因为小（〜125毫秒）。 </li><li>平均多个运行在每个会议记录，以提高信噪比。 </li><li>从fMRI的会议结构的数据对齐参考结构体积，使用一个强大的基于强度注册算法8。加载进入mrVista对齐和分割。 </li><li>转变职能的时间序列数据分割的参考量。在下面的步骤中，我们使用在我们的实验室开发的工具，以进行进一步的分析。 </li><li>通过计算每个SC组织体素和其最近在SC上表面的顶点之间的距离，计算距离图。这些距离是用来测量参考体积内的层的位置。 </li><li>执行层的分割过程，使时间序列数据的深度平均改善日é信噪比。小（直径1.6毫米）的组织与磁盘表面肤浅的资深大律师在整个表面模型的每个顶点，每个磁盘，然后扩展使用本地的表面法线形成一个单独的层附近的抵港及离港从SC组织4。 </li><li>对于每个SC上的表面来看，我们使用这些层协会指定的深度范围内平均的时间序列。由于视觉反应神经元主要是在目前的SC浅层，视觉刺激实验中，我们用了0-1.8毫米的深度范围。 </li></ol> 7。地形图分析分析地形数据表示，相干分析水深平均的时间序列进行拟合每个像素在刺激重复频率的正弦波（即1/24赫兹以上所述的24秒刺激）。从这个合适，我们推导出respon表面地图SE幅度，一致性和相位。这在频域进行分析，是一种常见的技术量化视觉皮层9,10 retinotopic地图。 正弦拟合阶段措施的刺激位置。零相位对应于垂直子午线上（ 图3）。然后按顺时针方向旋转的刺激，所以π/ 2相对应的刺激时，旋转至水平子午线在右视野。 π弧度的阶段后，刺激跨越到左边的视野，等等。 我们也得到了整个表面的SC使用手册高分辨率T1加权量解剖检验的程度界线。这些边界标记图。 3，红色虚线。 功能磁共振成像并不直接测量神经活动，而是血液流动的反应是紧紧，但缓慢加上神经活动。这增加了血流动力学的相位响应延迟。延迟估计从每个SC地区的利益，我们的连贯性阈值以上的所有像素，并围绕在复平面π的手段。在我们的资深大律师的数据，这些延迟非常小，为了2-4秒。我们删除旋转逆时针45度（相当于3秒）（ 图3）colormap的延迟。 8。代表结果 SC（ 图3）三维表面上覆盖相数据显示，视觉刺激的反应表示对侧的SC，即左视野右边的资深大律师代表和副，反之亦然。 还有的活动retinotopic组织。左丘（蓝色，洋红色）代表内侧右上视野，横向低场代表（红黄色）。 similarly，左上视野代表中间右侧丘（蓝青色）和较低的横向代表（黄绿色）。 这地形与供应链反应的非人类灵长类动物研究的结果是一致的：1）使用单一的单元电的视觉刺激，2）微刺激诱 ​​导扫视眼球运动11,12的映射。 <img alt="图1" src="/files/ftp_upload/3746/3746fig1.jpg" /> 图1。中旬矢状图像上观看）片处方。获得从中央切片中）在红色标记）功能图像的平均时间（从1运行）。 <img alt="图2" src="/files/ftp_upload/3746/3746fig2.jpg" /> 图2。的极地角度地形刺激。一个移动一个灰色的背景上的黑色和白色的点旋转90°楔慢慢靠近固定。楔形分为6古董，艺术品阵列人部门（灰线补充强调部门）允许主体执行速度歧视任务中随机选择一个部门。 <img alt="图3" src="/files/ftp_upload/3746/3746fig3.jpg" /> 图3。分割和表面建模。一）中脑，脑干，丘脑的部分分割的高分辨率MRI解剖卷。 B）表面分割区域的边缘。 c）合适的正弦相位数据看作一个面内片（连贯性&gt; 0.25）。 D）旋转，放大，脑干表面模型被用来阶段SC上的数据可视化。 <img alt="图4" src="/files/ftp_upload/3746/3746fig4.jpg" /> 图4。极角的地图。两个科目的fMRI相图，视觉极角编码。每个地图的连贯性阈值在右下角。色轮与刺激的叠加阶段，在pOLAR的角度，以他们的视野位置。

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没有利益冲突的声明。

我们的采集和数据分析技术，使测量的高分辨率（1.2毫米像素）人类大脑皮质结构的神经活动。 3杆的螺旋收购减少了生理的噪音，特别是不利于周围的脑功能磁共振成像测量。此外，我们的组织层分割，允许我们进行深入的数据，有助于提高信噪比平均。我们使用这些方法来显示精确的极角地形图的视觉刺激和视觉注意隐蔽在人类SC 1。层分割，也使实验控制下1不同的功能活动?...

high-resolution functional magnetic resonance imaging methods for human midbrain

功能磁共振成像（fMRI）技术是一种非侵入性测量人类大脑活动的相关广泛使用的工具。然而，它的使用大多集中后测量大脑皮质的表面，而不是在皮质下区域，如脑和脑干的活动。皮质功能磁共振成像必须克服两大挑战：空间分辨率和生理噪音。在这里，我们描述的制定执行，在中脑的背侧表面的结构在人类SC高分辨率功能磁共振成像技术的优化方法也可用于图像等脑干和皮层下结构。 高分辨率（1.2毫米像素）的资深大律师的功能磁共振成像需要一个非传统的方法。使用多杆（交错）的螺旋收购1，获得所需的空间采样。由于T 2 * SC的组织是长于皮层，相应的回波时间较长（T E〜40毫秒）用于为最大健康迈兹功能。到涵盖完整程度的SC，8-10片。为每个会话结构解剖也得到相同的功能磁共振成像片处方，这是用来对齐功能的数据到一个高分辨率的参考量。 在一个单独的会话，每个主题中，我们创建一个高分辨率（0.7毫米采样） 使用 T 1加权序列提供了良好的组织对比度的参考量。在参考量，中脑区域分割使用ITK的SNAP软件应用2。这种分割是用来创建一个三维表面的脑，是顺利和准确的3表示。表面顶点和法线用于创建地图从脑表面的深度范围内组织4。 功能数据转化成坐标系统分割的参考量。深入协会的像素使平均的fMRI时间序列数据，在指定的深度范围内，以提高信号质量。数据可视化三维表面呈现。 在我们的实验室中，我们使用这项技术在SC 1的视觉刺激和视觉注意隐蔽和公开的地形图测量。作为一个例子，我们表现出极角的地形表示SC视觉刺激。

Watch this Scientific Journal Video about High-resolution Functional Magnetic Resonance Imaging Methods for Human Midbrain at JoVE.com

High-resolution Functional Magnetic Resonance Imaging Methods for Human Midbrain

本文介绍了使用3T扫描仪在人脑和皮层下结构与1.2毫米采样高分辨率功能磁共振成像技术来执行。使用这些技术来解决视觉刺激在人类上丘（SC）的地形图作为一个例子。

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 ...

high-resolution-functional-magnetic-resonance-imaging-methods-for

Research

JoVE Journal

Neuroscience

12.7K 次观看.  The University of Texas at Austin. 本文介绍了使用3T扫描仪在人脑和皮层下结构与1.2毫米采样高分辨率功能磁共振成像技术来执行。使用这些技术来解决视觉刺激在人类上丘（SC）的地形图作为一个例子。

视频: High-resolution Functional Magnetic Resonance Imaging Methods for Human Midbrain

Multiple-mouse Neuroanatomical Magnetic Resonance Imaging

The field of mouse phenotyping with magnetic resonance imaging (MRI) is rapidly growing, motivated by the need for improved tools for characterizing and evaluating mouse models of human disease. MRI is an excellent modality for investigating genetically altered animals. It is capable of whole brain coverage, can be used in vivo, and provides multiple contrast mechanisms for investigating different aspects of neuranatomy and physiology. The advent of high-field scanners along with the ability to scan multiple mice simultaneously allows for rapid phenotyping of novel mutations.
Effective mouse MRI studies require attention to many aspects of experiment design. In this article, we will describe general methods to acquire quality images for mouse phenotyping using a system that images mice concurrently in shielded transmit/receive radio frequency (RF) coils in a common magnet (Bock et al., 2003). We focus particularly on anatomical phenotyping, an important and accessible application that has shown a high potential for impact in many mouse models at our imaging centre. Before we can provide the detailed steps to acquire such images, there are important practical considerations for both in vivo brain imaging (Dazai et al., 2004) and ex vivo brain imaging (Spring et al., 2007) that should be noted. These are discussed below.

Magnetic resonance imaging (MRI) has become an increasingly popular tool for examining the phenotype of genetically altered mice. This article illustrates the methods necessary to achieve high-throughput phenotyping of genetically altered mice using multiple-mouse MRI.

多鼠神经解剖学磁共振成像

The field of mouse phenotyping with magnetic resonance imaging (MRI) is rapidly growing, motivated by the need for improved tools for characterizing and ...

科研

神经科学

A Rapid Approach to High-Resolution Fluorescence Imaging in Semi-Thick Brain Slices

A fundamental goal to both basic and clinical neuroscience is to better understand the identities, molecular makeup, and patterns of connectivity that are characteristic to neurons in both normal and diseased brain. Towards this, a great deal of effort has been placed on building high-resolution neuroanatomical maps1-3. With the expansion of molecular genetics and advances in light microscopy has come the ability to query not only neuronal morphologies, but also the molecular and cellular makeup of individual neurons and their associated networks4. Major advances in the ability to mark and manipulate neurons through transgenic and gene targeting technologies in the rodent now allow investigators to 'program' neuronal subsets at will5-6. Arguably, one of the most influential contributions to contemporary neuroscience has been the discovery and cloning of genes encoding fluorescent proteins (FPs) in marine invertebrates7-8, alongside their subsequent engineering to yield an ever-expanding toolbox of vital reporters9. Exploiting cell type-specific promoter activity to drive targeted FP expression in discrete neuronal populations now affords neuroanatomical investigation with genetic precision.
Engineering FP expression in neurons has vastly improved our understanding of brain structure and function. However, imaging individual neurons and their associated networks in deep brain tissues, or in three dimensions, has remained a challenge. Due to high lipid content, nervous tissue is rather opaque and exhibits auto fluorescence. These inherent biophysical properties make it difficult to visualize and image fluorescently labelled neurons at high resolution using standard epifluorescent or confocal microscopy beyond depths of tens of microns. To circumvent this challenge investigators often employ serial thin-section imaging and reconstruction methods10, or 2-photon laser scanning microscopy11. Current drawbacks to these approaches are the associated labor-intensive tissue preparation, or cost-prohibitive instrumentation respectively.
Here, we present a relatively rapid and simple method to visualize fluorescently labelled cells in fixed semi-thick mouse brain slices by optical clearing and imaging. In the attached protocol we describe the methods of: 1) fixing brain tissue in situ via intracardial perfusion, 2) dissection and removal of whole brain, 3) stationary brain embedding in agarose, 4) precision semi-thick slice preparation using new vibratome instrumentation, 5) clearing brain tissue through a glycerol gradient, and 6) mounting on glass slides for light microscopy and z-stack reconstruction (Figure 1).
For preparing brain slices we implemented a relatively new piece of instrumentation called the 'Compresstome' VF-200 (http://www.precisionary.com/products_vf200.html). This instrument is a semi-automated microtome equipped with a motorized advance and blade vibration system with features similar in function to other vibratomes. Unlike other vibratomes, the tissue to be sliced is mounted in an agarose plug within a stainless steel cylinder. The tissue is extruded at desired thicknesses from the cylinder, and cut by the forward advancing vibrating blade. The agarose plug/cylinder system allows for reproducible tissue mounting, alignment, and precision cutting. In our hands, the 'Compresstome' yields high quality tissue slices for electrophysiology, immunohistochemistry, and direct fixed-tissue mounting and imaging. Combined with optical clearing, here we demonstrate the preparation of semi-thick fixed brain slices for high-resolution fluorescent imaging.

Here we describe a rapid and simple method to image fluorescently labeled cells in semi-thick brain slices. By fixing, slicing, and optically clearing brain tissue we describe how standard epifluorescent or confocal imaging can be used to visualize individual cells and neuronal networks within intact nervous tissue.

一个快速高分辨率的荧光成像的方法在半厚的脑片

A fundamental goal to both basic and clinical neuroscience is to better understand the identities, molecular makeup, and patterns of connectivity that are ...

The Use of Magnetic Resonance Spectroscopy as a Tool for the Measurement of Bi-hemispheric Transcranial Electric Stimulation Effects on Primary Motor Cortex Metabolism

Transcranial direct current stimulation (tDCS) is a neuromodulation technique that has been increasingly used over the past decade in the treatment of neurological and psychiatric disorders such as stroke and depression. Yet, the mechanisms underlying its ability to modulate brain excitability to improve clinical symptoms remains poorly understood 33. To help improve this understanding, proton magnetic resonance spectroscopy (1H-MRS) can be used as it allows the in vivo quantification of brain metabolites such as &#947;-aminobutyric acid (GABA) and glutamate in a region-specific manner 41. In fact, a recent study demonstrated that 1H-MRS is indeed a powerful means to better understand the effects of tDCS on neurotransmitter concentration 34. This article aims to describe the complete protocol for combining tDCS (NeuroConn MR compatible stimulator) with 1H-MRS at 3 T using a MEGA-PRESS sequence. We will describe the impact of a protocol that has shown great promise for the treatment of motor dysfunctions after stroke, which consists of bilateral stimulation of primary motor cortices 27,30,31. Methodological factors to consider and possible modifications to the protocol are also discussed.

This article aims to describe a basic protocol for combining transcranial direct current stimulation (tDCS) with proton magnetic resonance spectroscopy (1H-MRS) measurements to investigate the effects of bilateral stimulation on primary motor cortex metabolism.

磁共振波谱的用途，用于对初级运动皮层新陈代谢双半球经颅电刺激效果的测量工具一

Transcranial direct current stimulation (tDCS) is a neuromodulation technique that has been increasingly used over the past decade in the treatment of ...

Metabolomic Analysis of Rat Brain by High Resolution Nuclear Magnetic Resonance Spectroscopy of Tissue Extracts

Studies of gene expression on the RNA and protein levels have long been used to explore biological processes underlying disease. More recently, genomics and proteomics have been complemented by comprehensive quantitative analysis of the metabolite pool present in biological systems. This strategy, termed metabolomics, strives to provide a global characterization of the small-molecule complement involved in metabolism. While the genome and the proteome define the tasks cells can perform, the metabolome is part of the actual phenotype. Among the methods currently used in metabolomics, spectroscopic techniques are of special interest because they allow one to simultaneously analyze a large number of metabolites without prior selection for specific biochemical pathways, thus enabling a broad unbiased approach. Here, an optimized experimental protocol for metabolomic analysis by high-resolution NMR spectroscopy is presented, which is the method of choice for efficient quantification of tissue metabolites. Important strengths of this method are (i) the use of crude extracts, without the need to purify the sample and/or separate metabolites; (ii) the intrinsically quantitative nature of NMR, permitting quantitation of all metabolites represented by an NMR spectrum with one reference compound only; and (iii) the nondestructive nature of NMR enabling repeated use of the same sample for multiple measurements. The dynamic range of metabolite concentrations that can be covered is considerable due to the linear response of NMR signals, although metabolites occurring at extremely low concentrations may be difficult to detect. For the least abundant compounds, the highly sensitive mass spectrometry method may be advantageous although this technique requires more intricate sample preparation and quantification procedures than NMR spectroscopy. We present here an NMR protocol adjusted to rat brain analysis; however, the same protocol can be applied to other tissues with minor modifications.

The neurochemistry of mammalian brain is changed in many neurological and systemic diseases. Characteristic profiles of cerebral metabolites can be efficiently obtained based on crude extracts of brain tissue. To this end, high-resolution NMR spectroscopy is employed, enabling detailed quantitative analysis of metabolite concentrations (metabolomics).

大鼠脑组织被提取物的高分辨核磁共振代谢组学分析

Studies of gene expression on the RNA and protein levels have long been used to explore biological processes underlying disease. More recently, genomics ...

High-resolution In Vivo Manual Segmentation Protocol for Human Hippocampal Subfields Using 3T Magnetic Resonance Imaging

The human hippocampus has been broadly studied in the context of memory and normal brain function and its role in different neuropsychiatric disorders has been heavily studied. While many imaging studies treat the hippocampus as a single unitary neuroanatomical structure, it is, in fact, composed of several subfields that have a complex three-dimensional geometry. As such, it is known that these subfields perform specialized functions and are differentially affected through the course of different disease states. Magnetic resonance (MR) imaging can be used as a powerful tool to interrogate the morphology of the hippocampus and its subfields. Many groups use advanced imaging software and hardware (&#62;3T) to image the subfields; however this type of technology may not be readily available in most research and clinical imaging centers. To address this need, this manuscript provides a detailed step-by-step protocol for segmenting the full anterior-posterior length of the hippocampus and its subfields: cornu ammonis (CA) 1, CA2/CA3, CA4/dentate gyrus (DG), strata radiatum/lacunosum/moleculare (SR/SL/SM), and subiculum. This protocol has been applied to five subjects (3F, 2M; age 29-57, avg. 37). Protocol reliability is assessed by resegmenting either the right or left hippocampus of each subject and computing the overlap using the Dice&#39;s kappa metric. Mean Dice&#39;s kappa (range) across the five subjects are: whole hippocampus, 0.91 (0.90-0.92); CA1, 0.78 (0.77-0.79); CA2/CA3, 0.64 (0.56-0.73); CA4/dentate gyrus, 0.83 (0.81-0.85); strata radiatum/lacunosum/moleculare, 0.71 (0.68-0.73); and subiculum 0.75 (0.72-0.78). The segmentation protocol presented here provides other laboratories with a reliable method to study the hippocampus and hippocampal subfields in vivo using commonly available MR tools.

High-resolution In Vivo Manual Segmentation Protocol for Human Hippocampal Subfields Using 3T Magnetic Resonance Imaging

The goal of this manuscript is to study the hippocampus and hippocampal subfields using MRI. The manuscript describes a protocol for segmenting the hippocampus and five hippocampal substructures: cornu ammonis (CA) 1, CA2/CA3, CA4/dentate gyrus, strata radiatum/lacunosum/moleculare, and subiculum.

高分辨率<em&gt;在体内</em&gt;使用3T磁共振成像手动分割协议为人类海马子字段

The human hippocampus has been broadly studied in the context of memory and normal brain function and its role in different neuropsychiatric disorders has ...

High-resolution Structural Magnetic Resonance Imaging of the Human Subcortex In Vivo and Postmortem

The focus of this study was to test the resolution limits of structural MRI of a postmortem brain compared to living human brains. The resolution of structural MRI in vivo is ultimately limited by physiological noise, including pulsation, respiration and head movement. Although imaging hardware continues to improve, it is still difficult to resolve structures on the millimeter scale. For example, the primary visual sensory pathways synapse at the lateral geniculate nucleus (LGN), a visual relay and control nucleus in the thalamus that normally is organized into six interleaved monocular layers. Neuroimaging studies have not been able to reliably distinguish these layers due their small size that are less than 1 mm thick.
The resolving limit of structural MRI, in a postmortem brain was tested using multiple images averaged over a long duration (~24 h). The purpose was to test whether it was possible to resolve the individual layers of the LGN in the absence of physiological noise. A proton density (PD)1 weighted pulse sequence was used with varying resolution and other parameters to determine the minimum number of images necessary to be registered and averaged to reliably distinguish the LGN and other subcortical regions. The results were also compared to images acquired in living human brains. In vivo subjects were scanned in order to determine the additional effects of physiological noise on the minimum number of PD scans needed to differentiate subcortical structures, useful in clinical applications.

High-resolution Structural Magnetic Resonance Imaging of the Human Subcortex In Vivo and Postmortem

Here we present a protocol to determine the minimum number images that needed to be registered and averaged to resolve subcortical structures and test whether the individual layers of the LGN could be resolved in the absence of physiological noise.

高分辨率结构磁共振人类皮质下的成像<I&gt;在体内</I&gt;与死亡

The focus of this study was to test the resolution limits of structural MRI of a postmortem brain compared to living human brains. The resolution of ...

Acquisition of Resting-State Functional Magnetic Resonance Imaging Data in the Rat

Resting-state functional magnetic resonance imaging (rs-fMRI) has become an increasingly popular method to study brain function in a resting, non-task state. This protocol describes a preclinical survival method for obtaining rs-fMRI data. Combining low dose isoflurane with continuous infusion of the &#945;2 adrenergic receptor agonist dexmedetomidine provides a robust option for stable, high-quality data acquisition while preserving brain network function. Furthermore, this procedure allows for spontaneous breathing and near-normal physiology in the rat. Additional imaging sequences can be combined with resting-state acquisition creating experimental protocols with anesthetic stability of up to 5 h using this method. This protocol describes the setup of equipment, monitoring of rat physiology during four distinct phases of anesthesia, acquisition of resting-state scans, quality assessment of data, recovery of the animal, and a brief discussion of post-processing data analysis. This protocol can be used across a wide variety of preclinical rodent models to help reveal the resulting brain network changes that occur at rest.

This protocol describes a method for obtaining stable resting-state functional magnetic resonance imaging (rs-fMRI) data from a rat using low dose isoflurane in combination with low dose dexmedetomidine.

获取大鼠的静态功能磁共振成像数据

Resting-state functional magnetic resonance imaging (rs-fMRI) has become an increasingly popular method to study brain function in a resting, non-task ...

Endovascular Perforation Model for Subarachnoid Hemorrhage Combined with Magnetic Resonance Imaging (MRI)

The endovascular filament perforation model to mimic subarachnoid hemorrhage (SAH) is a commonly used model - however, the technique can cause a high mortality rate as well as an uncontrollable volume of SAH and other intracranial complications such as stroke or intracranial hemorrhage. In this protocol, a standardized SAH mouse model is presented, induced by endovascular filament perforation, combined with magnetic resonance imaging (MRI) 24 h after operation to ensure the correct bleeding site and exclude other relevant intracranial pathologies. Briefly, C57BL/6J mice are anesthetized with an intraperitoneal ketamine/xylazine (70 mg/16 mg/kg body weight) injection and placed in a supine position. After midline neck incision, the common carotid artery (CCA) and carotid bifurcation are exposed, and a 5-0 non-absorbable monofilament polypropylene suture is inserted in a retrograde fashion into the external carotid artery (ECA) and advanced into the common carotid artery. Then, the filament is invaginated into the internal carotid artery (ICA) and pushed forward to perforate the anterior cerebral artery (ACA). After recovery from surgery, mice undergo a 7.0 T MRI 24 h later. The volume of bleeding can be quantified and graded via postoperative MRI, enabling a robust experimental SAH group with the option to perform further subgroup analyses based on blood quantity.

Endovascular Perforation Model for Subarachnoid Hemorrhage Combined with Magnetic Resonance Imaging MRI

Here we present a standardized SAH mouse model, induced by endovascular filament perforation, combined with magnetic resonance imaging (MRI) 24 h after operation to ensure the correct bleeding site and exclude other relevant intracranial pathologies.

蛛网膜下腔出血结合磁共振成像（MRI）的血管内穿孔模型

The endovascular filament perforation model to mimic subarachnoid hemorrhage (SAH) is a commonly used model - however, the technique can cause a high ...

A Standardized Pipeline for Examining Human Cerebellar Grey Matter Morphometry using Structural Magnetic Resonance Imaging

Multiple lines of research provide compelling evidence for a role of the cerebellum in a wide array of cognitive and affective functions, going far beyond its historical association with motor control. Structural and functional neuroimaging studies have further refined understanding of the functional neuroanatomy of the cerebellum beyond its anatomical divisions, highlighting the need for the examination of individual cerebellar subunits in healthy variability and neurological diseases. This paper presents a standardized pipeline for examining cerebellum grey matter morphometry that combines high-resolution, state-of-the-art approaches for optimized and automated cerebellum parcellation (Automatic Cerebellum Anatomical Parcellation using U-Net Locally Constrained Optimization; ACAPULCO) and voxel-based registration of the cerebellum (Spatially Unbiased Infra-tentorial Template; SUIT) for volumetric quantification. 
The pipeline has broad applicability to a range of neurological diseases and is fully automated, with manual intervention only required for quality control of the outputs. The pipeline is freely available, with substantial accompanying documentation, and can be run on Mac, Windows, and Linux operating systems. The pipeline is applied in a cohort of individuals with Friedreich ataxia (FRDA), and representative results, as well as recommendations on group-level inferential statistical analyses, are provided. This pipeline could facilitate reliability and reproducibility across the field, ultimately providing a powerful methodological approach for characterizing and tracking cerebellar structural changes in neurological diseases.

A standardized pipeline is presented for examining cerebellum grey matter morphometry. The pipeline combines high-resolution, state-of-the-art approaches for optimized and automated cerebellum parcellation and voxel-based registration of the cerebellum for volumetric quantification.

一种使用结构磁共振成像检查人小脑灰质形态测量的标准化管道

Multiple lines of research provide compelling evidence for a role of the cerebellum in a wide array of cognitive and affective functions, going far beyond ...

Magnetic Resonance-Guided Stereotaxy for Infusions to the Pig Brain

The overall goal of this procedure is to perform stereotaxy in the pig brain with real-time magnetic resonance (MR) visualization guidance to provide precise infusions. The subject was positioned prone in the MR bore for optimal access to the top of the skull with the torso raised, the neck flexed, and the head inclined downward. Two anchor pins anchored on the bilateral zygoma held the head steady using the head holder. A magnetic resonance imaging (MRI) flex-coil was placed rostrally across the head holder so that the skull was accessible for the intervention procedure. A planning grid placed on the scalp was used to determine the appropriate entry point of the cannula. The stereotactic frame was secured and aligned iteratively through software projection until the projected radial error was less than 0.5 mm. A hand drill was used to create a burr hole for insertion of the cannula. A gadolinium-enhanced co-infusion was used to visualize the infusion of a cell suspension. Repeated T1-weighted MRI scans were registered in real time during the agent delivery process to visualize the volume of gadolinium distribution. MRI-guided stereotaxy allows for precise and controlled infusion into the pig brain, with concurrent monitoring of cannula insertion accuracy and determination of the agent volume of distribution.

The protocol presented here demonstrates stereotaxy to the pig brain using convection-enhanced infusions, with real-time magnetic resonance imaging (MRI) visualization guidance and real-time infusion distribution visualization.

磁共振引导立体定向输注猪脑

The overall goal of this procedure is to perform stereotaxy in the pig brain with real-time magnetic resonance (MR) visualization guidance to provide ...