The authors acknowledge the following funding sources, the Natural Sciences and Engineering Research Council of Canada (NSERC), the Dorothy Pitts Research Fund (NG), and the Nicky and Thor Eaton Research Fund. The authors acknowledge Kevin DeSimone, and Aman Goyal and for their knowledge in MRI acquisition and analysis expertise.

1.参与者和死后的大脑建立注:使用3个T磁共振成像扫描仪具有32通道头线圈和所有的MRI扫描被收购所有图像在RT进行，约20℃。所有与会者都用右手，并签署知情同意书。每个参加者是在良好的健康与神经系统疾病史。实验方案获得批准，遵循约克大学人类受试者审查委员会的指导方针。 <ol><li>要求每个参与者填写并签署，详细MRI安全准则和神经影像学协议病人的知情同意书。 </li><li>对于每个参与者，将耳塞的每只耳朵和保护他们的头垫，以尽量减少头部运动。 </li><li>对于验尸脑成像，确保之前的神经影像学大脑是固定的，包含在该MRI头部线圈的夹缝之中袋或容器。将死后的大脑中的头部线圈，其z轴（优于INFerior）对准用扫描器的孔。脑干（后）应朝向扫描仪床脚。 </li><li>将真空垫手周围的验尸的大脑获得更多支持。 </li></ol> 2，本地化和处方皮层下注:丘脑是位于位于中脑和大脑皮层之间的大脑中央的双裂结构。位于背侧丘脑中，人的LGN是一个小的皮质下结构，扩展最大至10毫米。 <ol><li>要注册一个新的参与者，打开核磁共振成像软件并点击左上角的患者标签。然后点击注册。 </li><li>在合适的患者填写信息，然后单击考试选项卡。 </li><li>为了获得一个定位扫描，点击考试资源管理器选项卡上创建一个新的协议。观察设置窗口在屏幕上，单击常规选项卡，并输入以下参数:收购时间28秒，采集矩阵160×160，1片，厚1.6毫米的各向同性体素尺寸，FOV = 260毫米，相的FoV = 100％，切片分辨率= 69％，相位和切片部分相傅里叶= 6/8，TR = 3.15毫秒，TE = 1.37毫秒，翻转角= 8°。 </li><li>叠加用于获取对PD图象在定位覆盖丘脑内皮层下细胞核以及周围结构（图4）的切片选择框。 </li></ol> 3.高分辨率结构参数<ol><li>创建获取高分辨率的PD加权扫描一个新的协议。在屏幕上的设置窗口中，单击常规选项卡，并输入在冠状方向以下参数:采集时间179秒，采集矩阵512×512，0.3×0.3×1 立方毫米像素大小，TR = 3.25秒，TE = 32毫秒，翻转角= 120°，交错片采集，读取的FoV = 160毫米，相的FoV = 100％，平行成像（GRAPPA）与为2的加速因子。 <ol><li>使用快速自旋回波序列，与5。第一回波在32毫秒的回声列车长度为有效呼应此序列。减少带宽（BW），以最小的可能，40赫兹/像素，以最大化信噪比。为了减少扫描时间，选择18片，每次1毫米厚，与FOV = 160毫米。该板提供了足够的覆盖范围感兴趣皮质下区域。 注:为了保证可靠的识别皮层下结构，获得5次操作，上述参数。总的扫描持续时间仅为〜15分钟（ 图5）。脂肪的饱和度没有采用。 </li></ol></li><li>在验尸脑成像，可靠识别皮层下结构可以只在一个扫描中观察到的唯一〜3分钟以下的相同的扫描协议为在3.1（图6）的总持续时间。 </li></ol> 4.图像分析注:要分析MRI数据，使用免费提供的FMRIB的软件库（FSL）包可供下载<a href="https://www.fmrib.ox.ac.uk/fsl/">（https://www.fmrib.ox.ac.uk/fsl/）。</a> <ol><li>打开一个终端窗口，并从扫描仪对每个PD卷到NIfTI格式与DICOM到NIfTI转换器转换成原始DICOM文件。都可以免费下载其中一些（例如<a href="https://www.nitrc.org/projects/mricron">，https://www.nitrc.org/projects/mricron）。</a>在命令行中键入dc​​m2nii其次是每个PD加权像奔跑的目录。 </li><li>在终端窗口得到原始的PD扫描的参数。在命令行随后在NIfTI格式PD扫描类型fslinfo。 </li><li>创建高分辨率空白图像目标卷具有该分辨率的两倍和由参数从fslinfo从原来的PD扫描给定的一半的体素尺寸。是数据输入该命令的命令如下: fslcreatehd &lt;xsize&gt; &lt;ysize&gt; &lt;ž大小&gt; &lt;TSIZE&gt; &lt;xvoxsize&gt; &lt;yvoxsize&gt; &lt;zvoxsize&gt; &lt;TR&gt; &lt;xorigin&gt; &lt;yorigin&gt; &lt;zorigin&gt; &lt;数据类型&gt; &lt;headername&gt; 注:例如，如果与在3.1中所述的下列参数原来的PD扫描收集（ 即 512×512矩阵，18片，0.3×0.3×1 立方毫米像素大小，TR = 3.25 S），键入以下在命令窗口中: fslcreatehd 1024×1024 36 1 0.15 0.15 0.5 3.25 0 0 0 4 blankhr.nii.gz </li><li>定义使用单位矩阵的转变。键入任何文本编辑器程序的文本文件保存为"identity.mat"，看起来像这样: 0 0 0 1 0 0 0 1 0 0 0 1 </li><li>使用调情命令应用转换，上采样每个原始PD加权运行从512的总分辨率增加一倍，达到1024矩阵，减半体素大小在每个维度造成0.15×0.15的分辨率×0.5 立方毫米。在终端窗口中的每个PD卷，键入以下命令调情改变每个运行原始和输出的名称: 调情-interp正弦-in originalPD.nii.gz -ref blankhr.nii.gz -applyxfm -init identity.mat退房手续highresPD.nii.gz 注:其中originalPD.nii.gz是源卷，blankhr.nii.gz是所需的输出分辨率，并且highresPD.nii.gz是输出卷的名称。 </li><li>将所有的高分辨率图像到一个新的文件夹，然后导航到在一个终端窗口。 </li><li>对于每一个参与者，串接所有采样的局部放电图像转换成使用fslmerge一个4D文件。在终端窗口中输入: fslmerge -t concat_highresPD * .nii.gz 注:此创建一个名为concat_highresPD.nii.gz四维文件。 </li><li>使用mcflirt 10动态校正串联文件。该工具允许一个强大的自动注册线性（仿射）间及多式联运的大脑图像。选择4级校正，其利用正弦内插（内部），为进一步优化过程获得更高的精度。在终端窗口中输入: mcflirt -in concat_highresPD退房手续mcf_concat_highresPD.nii.gz -stages 4 -plots 注:此创建一个名为mcf_concat_highresPD.nii.gz四维文件。 </li><li>最后，创建3D意味着使用图像fslmaths。在终端窗口中输入: fslmaths mcf_concat_highresPD.nii.gz -Tmean mean_highresPD.nii.gz 注:此创建一个名为mean_highresPD.nii.gz一个3D文件，是高品质的</li><li>可视化使用fslview命令的最终结果的3D高清晰度的图像。在其中，您的图片所在的目录，键入一个终端窗口如下: fslview mean_highresPD.nii.gz。" </li><li>有关检查ROI的强度分布。创建使用fslview的ROI（这可以是跨LGN的区域画出的实施例的垂直线）。在fslview加载高分辨率的PD图象。单击工具选项卡上，然后点击单个图像选项卡上的放大图像绘制的ROI。然后，单击文件选项卡随后创建模板标签。绘制在感兴趣的ROI的线。通过单击文件，然后另存为保存的投资回报率。投资回报率的强度比较，并在问题的其他投资回报之内重复线路口罩多个领域。 </li><li>使用AFNI的3dmaskdump命令来分析所得的图像的强度。投资回报率面具在那里的图像，使用以下命令在终端窗口提取图像亮度和位置的目录（给出result_mask.txt）: 3dmaskdump -o result_mask.txt -noijk -xyz -mask ROI_linemask.nii.gz PDaverage_image.nii.gz </li></ol>

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The authors have nothing to disclose.

该研究描述了为了得到皮质下区域的高分辨率的PD加权图像采集和分析技术的优化协议。一些扫描参数进行了测试，并修改与最显著那些关于矩阵大小，体素尺寸和带宽，以增加信噪比和减少收购的数量，在能够确定的高分辨率皮质结构的关键步骤。在与人类的生活中找到最佳参数一起使用，这项研究测试的理想条件下的核磁共振成像扫描仪的绝对限制，没有运动伪影和患者的时间限制通过扫描?...

这项研究的目的是测试结构性MRI的分辨率限制在没有生理噪声。质子密度（PD）的加权图像在死后的大脑获得在较长的持续时间（2〜24小时，会话），以确定需要被登记的图像的最小数目并取平均值，以解决皮层下结构。为了比较，PD加权图像在活人在若干会话还获得。具体地，其目的是要确定它是否有可能在一个最好的情况下，以解决人类LGN的所有六个单独的层，这是大约1毫米厚的（图1）。 <img alt="图1" src="/files/ftp_upload/53309/53309fig1.jpg" /> 图1.人类外侧膝状体层，原理图LGN的层状结构。大细胞（M）的层由较大的神经元的细胞大小和更小的细胞密度是负责解决运动当然轮廓（层1-2，描绘为深灰色）。小细胞亚核层（P）是由较小的神经元细胞的尺寸和更大的细胞密度是负责解决精细形式和颜色（层4-6，描绘为浅灰色）。比例条1毫米。图的基础上染色的人LGN 12。 在MRI中的空间分辨率时，矩阵尺寸增大得到改善，而当字段的视图（FOV）和切片厚度被减少。然而，增加的分辨率降低了信号噪声比（SNR），这是成比例的体素的体积。信噪比也正比于测量次数的平方根。在人类的生活，尽管多个图像可以通过许多单独的成像会被收购，最终分辨率由生理噪声的限制，诸如呼吸，循环脉动和头部运动。 高- 分辨率（0.35毫米面体素），PD被收购加权扫描。 PD扫描提高灰色和白色的对比在丘脑1，并导致在最小化T1和T2 2的效果的图像。其图像是依赖于质子在水和大分子的形式，例如在成像体积的蛋白质和脂肪的密度。在一个组织中的结果在图像上亮信号质子由于磁化2的较高纵向分量的数量增加。 收集的PD加权扫描，因为它们提供皮层下结构与周围组织更高的对比度。其他的对比，如T1和T2加权像导致难以划定，如LGN皮层下结构，由于较小的对比噪声比，所确定的ƒ1,3。 同样，早期的研究发现福尔马林的PD加权像固定验尸的大脑resulte比T1和T2加权图像，也有类似的灰质和白质图像强度3,4 d在灰质和白质之间更高的对比度差异。底层生物物理因素可以解释这些差异。氢质子T1（纵向）和T2（横向）弛豫时间取决于水如何在组织内移动。固定剂，例如通过交联蛋白质福尔马林工作。被还原的不同组织类型之间的水流动性之间的差异，当固定剂的使用。减压T1组织对比度已固定后已经观察到，而在脑组织的增加而固定内质子的相对密度的差异，从而提供更好的对比度分化3,4。 使用1.5T的5,6,7以前的研究已经确定了LGN在PD加权扫描，并在3个T扫描仪8,9。要能精确地勾画的程度是至关重要的获得这些扫描在LGN。为了保持皮层下核的全覆盖，18 PD加权切片丘脑内获得。每个卷被重新采样到第1024矩阵两次，（0.15毫米的平面内的体素尺寸），级联，运动校正和平均化，以产生皮层下结构的高分辨率3D图像。所需以下切片处方的PD图像的最佳数量为5，从而减少扫描时间为小于15分钟，在活的人类。仅1 PD图象被要求明确地划分皮层下区域中的死后脑，减少扫描时间少于3分钟（ 图2 和 3）。 整整福尔马林固定死后的大脑标本采自于谁岁时死于心肺骤停82岁的女人扫描。审查病历显示，她有:慢性阻塞性肺疾病，心绞痛，三搭桥手术8年死前，子宫癌与子宫切除术7年之前死亡，高脂血症，青光眼，和白内障手术。死后脑样品浸没固定在10％中性缓冲福尔马林中至少3周，在4℃C.The死后的大脑进行扫描具有相同的成像协议，以及与其他参数超过许多小时的过程中进行的图像质量比较。仅优化参数将描述的协议。

<table><tbody><tr><td>Magnetom Trio 3T&amp;nbsp; MRI</td><td>Siemens (Erlangen, Germany).</td><td></td><td></td></tr><tr><td>Vacuum cushion hand</td><td>Siemens</td><td>Mat No: 4765454</td><td>Manufactured by: Johannes-Stark-Stk. 8 D-92224 Amberg</td></tr></tbody></table>

high-resolution structural magnetic resonance imaging of the human subcortex in vivo and postmortem

这项研究的重点是测试一个死后的大脑结构MRI相比，活体人脑的分辨率极限。结构的MRI的体内分辨率最终由生理噪声，包括脉动，呼吸和头部运动的限制。虽然成像硬件的不断提高，但仍难以解决结构上的毫米级。例如，在外侧膝状体初级视觉感觉通路突触（LGN），一个视觉继电器和控制核中，通常被组织成六个交错单眼层丘脑。神经影像学研究一直无法可靠地区别这些层由于它们的小尺寸是小于1毫米厚。 结构的MRI的分辨极限，在死后的大脑进行了测试用的多个图像平均长持续时间（〜24小时）。的目的是测试是否有可能解决各个升所述LGN在没有生理噪声的艾尔斯。质子密度（PD）1加权脉冲序列用于具有不同分辨率和其他参数来确定必要要登记的图像的最小数目并取平均值以可靠区分LGN和其他皮质下区域。结果进行了比较，以在活的人脑获取的图像。 体内受试者进行扫描，以确定对区分皮层下结构，在临床应用中有用的PD所需的最小扫描次数生理噪声的附加 ​​效果。

一旦皮层下被规定丘脑内，PD加权图像中的切片选择框（图4）收集。信噪比通过增加在两个死后和体内扫描平均次数提高。以确定的图像质量，从不同的扫描平均数信噪比是由在脑外的某些区域的平均脑区域的信号除以标准偏差进行比较。信噪比被计算为SNR = 0.655 *μ 组织 /σ 空气 11，其中，μ 组织表示脑区域内的ROI的平均像...

Watch this Scientific Journal Video about High-resolution Structural Magnetic Resonance Imaging of the Human Subcortex In Vivo and Postmortem at JoVE.com

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 ...

high-resolution-structural-magnetic-resonance-imaging-human-subcortex

Universidad de Cartagena UDEC

Research

JoVE Journal

Neuroscience

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

15.3K 次观看.  York University. 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. 

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

Registered Bioimaging of Nanomaterials for Diagnostic and Therapeutic Monitoring

Nanomedications can be carried by blood borne monocyte-macrophages into the reticuloendothelial system (RES; spleen, liver, lymph nodes) and to end organs. The latter include the lung, RES, and brain and are operative during human immunodeficiency virus type one (HIV-1) infection. Macrophage entry into tissues is notable in areas of active HIV-1 replication and sites of inflammation. In order to assess the potential of macrophages as nanocarriers, superparamagnetic iron-oxide and/or drug laden particles coated with surfactants were parenterally injected into HIV-1 encephalitic mice. This was done to quantitatively assess particle and drug biodistribution. Magnetic resonance imaging (MRI) test results were validated by histological coregistration and enhanced image processing. End organ disease as typified by altered brain histology were assessed by MRI. The demonstration of robust migration of nanoformulations into areas of focal encephalitis provides '"proof of concept" for the use of advanced bioimaging techniques to monitor macrophage migration. Importantly, histopathological aberrations in brain correlate with bioimaging parameters making the general utility of MRI in studies of cell distribution in disease feasible. We posit that using such methods can provide a real time index of disease burden and therapeutic efficacy with translational potential to humans.

Bioimaging methods used to assess cell biodistribution of nanoparticles are applicable for therapeutic and diagnostic monitoring of nanoformulated compounds. The methods described herein are sensitive and specific when assessed by histological coregistration. The methodologies provide a translational pathway from rodent to human applications.

注册生物成像，纳米材料可用于诊断和治疗监测

Nanomedications can be carried by blood borne monocyte-macrophages into the reticuloendothelial system (RES; spleen, liver, lymph nodes) and to end ...

科研

生物工程

Chronic Imaging of Mouse Visual Cortex Using a Thinned-skull Preparation

In vivo imaging using two-photon laser scanning microscopy (2PLSM) allows the study of living cells and neuronal processes in the intact brain. The technique presented here allows the imaging of the same area of the brain at several time points (chronic imaging) with microscopic resolution allowing the tracking of dendritic spines which are the small structures that represent the majority of postsynaptic excitatory sites in the CNS. The ability to clearly resolve fine cortical structures over several time points has many advantages, specifically in the study of brain plasticity in which morphological changes at synapses and circuit remodeling may help explain underlying mechanisms. In this video and supplementary material, we show a protocol for chronic in vivo imaging of the intact brain using a thinned-skull preparation. The thinned-skull preparation is a minimally invasive approach, which avoids potential damage to the dura and/or cortex, thus reducing the onset of an inflammatory response. When this protocol is performed correctly, it is possible to clearly monitor changes in dendritic spine characteristics in the intact brain over a prolonged period of time.

In this video and supplemental material, we show a protocol for chronic in vivo imaging of the intact brain using a thinned-skull preparation.

慢性成像小鼠的视觉皮层使用减薄，颅骨的制备

In vivo imaging using two-photon laser scanning microscopy (2PLSM) allows the study of living cells and neuronal processes in the intact brain. The ...

神经科学

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 ...

In vivo Imaging of Deep Cortical Layers using a Microprism

We present a protocol for in vivo imaging of cortical tissue using a deep-brain imaging probe in the shape of a microprism.  Microprisms are 1-mm in size and have a reflective coating on the hypotenuse to allow internal reflection of excitation and emission light.  The microprism probe simultaneously images multiple cortical layers with a perspective typically seen only in slice preparations.  Images are collected with a large field-of-view (~900 &mu;m).  In addition, we provide details on the non-survival surgical procedure and microscope setup.  Representative results include images of layer V pyramidal neurons from Thy-1 YFP-H mice showing their apical dendrites extending through the superficial cortical layer and extending into tufts.  Resolution was sufficient to image dendritic spines near the soma of layer V neurons.  A tail-vein injection of fluorescent dye reveals the intricate network of blood vessels in the cortex.  Line-scanning of red blood cells (RBCs) flowing through the capillaries reveals RBC velocity and flux rates can be obtained. This novel microprism probe is an elegant, yet powerful new method of visualizing deep cellular structures and cortical function in vivo.

In vivo Imaging of Deep Cortical Layers using a Microprism

Right-angle microprisms inserted into the mouse neocortex allows for deep imaging of multiple cortical layers with a viewpoint typically found in slice. One-millimeter microprisms offer a wide field-of-view (~900 &mu;m) and spatial resolutions sufficient to resolve dendritic spines. We demonstrate layer V neuronal imaging and neocortical vascular imaging using microprisms.

在使用微深皮质层的活体成像

We present a protocol for in vivo imaging of cortical tissue using a deep-brain imaging probe in the shape of a microprism.  Microprisms are 1-mm in size ...

生物学

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 ...

3D Modeling of the Lateral Ventricles and Histological Characterization of Periventricular Tissue in Humans and Mouse

The ventricular system carries and circulates cerebral spinal fluid (CSF) and facilitates clearance of solutes and toxins from the brain. The functional units of the ventricles are ciliated epithelial cells termed ependymal cells, which line the ventricles and through ciliary action are capable of generating laminar flow of CSF at the ventricle surface. This monolayer of ependymal cells also provides barrier and filtration functions that promote exchange between brain interstitial fluids (ISF) and circulating CSF. Biochemical changes in the brain are thereby reflected in the composition of the CSF and destruction of the ependyma can disrupt the delicate balance of CSF and ISF exchange. In humans there is a strong correlation between lateral ventricle expansion and aging. Age-associated ventriculomegaly can occur even in the absence of dementia or obstruction of CSF flow. The exact cause and progression of ventriculomegaly is often unknown; however, enlarged ventricles can show regional and, often, extensive loss of ependymal cell coverage with ventricle surface astrogliosis and associated periventricular edema replacing the functional ependymal cell monolayer. Using MRI scans together with postmortem human brain tissue, we describe how to prepare, image and compile 3D renderings of lateral ventricle volumes, calculate lateral ventricle volumes, and characterize periventricular tissue through immunohistochemical analysis of en face lateral ventricle wall tissue preparations. Corresponding analyses of mouse brain tissue are also presented supporting the use of mouse models as a means to evaluate changes to the lateral ventricles and periventricular tissue found in human aging and disease. Together, these protocols allow investigations into the cause and effect of ventriculomegaly and highlight techniques to study ventricular system health and its important barrier and filtration functions within the brain.

Using MRI scans (human), 3D imaging software, and immunohistological analysis, we document changes to the brain&#8217;s lateral ventricles. Longitudinal 3D mapping of lateral ventricle volume changes and characterization of periventricular cellular changes that occur in the human brain due to aging or disease are then modeled in mice.

脑室周围组织的侧脑室及组织学特性对人类和鼠标3D建模

The ventricular system carries and circulates cerebral spinal fluid (CSF) and facilitates clearance of solutes and toxins from the brain. The functional ...

Assessing Cortical Cerebral Microinfarcts on High Resolution MR Images

Cerebral microinfarcts are frequent findings in the post-mortem human brain, and are related to cognitive decline and dementia. Due to their small sizes it is challenging to study them on clinical MRI scans. It was recently demonstrated that cortical microinfarcts can be depicted with MRI scanners using high magnetic field strengths (7T). Based on this experience, a proportion of these lesions is also visible on lower resolution 3T MRI. These findings were corroborated with ex vivo imaging of post-mortem human brain tissue, accompanied by histopathological verification of possible cortical microinfarcts.
Here an ex vivo imaging protocol is presented, for the purpose of validating MR observed cerebral microvascular pathology with histological evaluation. Furthermore, guidelines are provided for the assessment of cortical microinfarcts on both in vivo 7T and 3T MR images. These guidelines provide researchers with a tool to rate cortical microinfarcts on in vivo images of larger patient samples, to further unravel their clinical relevance in cognitive decline and dementia, and establish these lesions as a novel biomarker of cerebral small vessel disease.

A high resolution ex vivo 7T MR imaging protocol is presented, to perform MR-guided histopathological validation of microvascular pathology in post-mortem human brain tissue. Furthermore, guidelines are provided for the assessment of cortical microinfarcts on in vivo 7T as well as 3T MR images.

评估皮层脑Microinfarcts高分辨率核磁共振图像

Cerebral microinfarcts are frequent findings in the post-mortem human brain, and are related to cognitive decline and dementia. Due to their small sizes ...

医学

Large-scale Three-dimensional Imaging of Cellular Organization in the Mouse Neocortex

The mammalian neocortex is composed of many types of excitatory and inhibitory neurons, each with specific electrophysiological and biochemical properties, synaptic connections, and in vivo functions, but their basic functional and anatomical organization from cellular to network scale is poorly understood. Here we describe a method for the three-dimensional imaging of fluorescently-labeled neurons across large areas of the brain for the investigation of the cortical cellular organization. Specific types of neurons are labeled by the injection of fluorescent retrograde neuronal tracers or expression of fluorescent proteins in transgenic mice. Block brain samples, e.g., a hemisphere, are prepared after fixation, made transparent with tissue clearing methods, and subjected to fluorescent immunolabeling of the specific cell types. Large areas are scanned using confocal or two-photon microscopes equipped with large working distance objectives and motorized stages. This method can resolve the periodic organization of the cell type-specific microcolumn functional modules in the mouse neocortex. The procedure can be useful for the study of three-dimensional cellular architecture in the diverse brain areas and other complex tissues.

Here we describe a procedure for tissue clearing, fluorescent labeling, and large-scale imaging of mouse brain tissue which, thereby, enables visualization of the three-dimensional organization of cell types in the neocortex.

小鼠大脑皮层细胞组织的大尺度三维成像

The mammalian neocortex is composed of many types of excitatory and inhibitory neurons, each with specific electrophysiological and biochemical ...

A Micro-CT-based Method for Characterizing Lesions and Locating Electrodes in Small Animal Brains

Lesion and electrode location verification are traditionally done via histological examination of stained brain slices, a time-consuming procedure that requires manual estimation. Here, we describe a simple, straightforward method for quantifying lesions and locating electrodes in the brain that is less laborious and yields more detailed results. Whole brains are stained with osmium tetroxide, embedded in resin, and imaged with a micro-CT scanner. The scans result in 3D digital volumes of the brains with resolutions and virtual section thicknesses dependent on the sample size (12&#8211;15 and 5&#8211;6 &#181;m&#160;per voxel for rat and zebra finch brains, respectively). Surface and deep lesions can be characterized, and single tetrodes, tetrode arrays, electrolytic lesions, and silicon probes can also be localized. Free and proprietary software allows experimenters to examine the sample volume from any plane and segment the volume manually or automatically. Because this method generates whole brain volume, lesions and electrodes can be quantified to a much higher degree than in current methods, which will help standardize comparisons within and across studies.

This article describes a straightforward method to prepare small animal brains for micro-CT imaging, in which lesions can be quantified and electrodes located with high precision in the context of the whole brain.

一种基于微 ct 的小动物脑损伤和定位电极表征方法

Lesion and electrode location verification are traditionally done via histological examination of stained brain slices, a time-consuming procedure that ...

Comprehensive Autopsy Program for Individuals with Multiple Sclerosis

We describe a rapid tissue donation program for individuals with multiple sclerosis (MS) that requires scientists and technicians to be on-call 24/7, 365 days a year. Participants consent to donate their brain and spinal cord. Most patients were followed by neurologists at the Cleveland Clinic Mellen Center for MS Treatment and Research. Their clinical courses and neurological disabilities are well-characterized. Soon after death, the body is transported to the MS Imaging Center, where the brain is scanned in situ by 3 T magnetic resonance imaging (MRI). The body is then transferred to the autopsy room, where the brain and spinal cord are removed. The brain is divided into two hemispheres. One hemisphere is immediately placed in a slicing box and alternate 1 cm-thick slices are either fixed in 4% paraformaldehyde for two days or rapidly frozen in dry ice and 2-methylbutane. The short-fixed brain slices are stored in a cryopreservation solution and used for histological analyses and immunocytochemical detection of sensitive antigens. Frozen slices are stored at -80 &#176;C and used for molecular, immunocytochemical, and in situ hybridization/RNA scope studies. The other hemisphere is placed in 4% paraformaldehyde for several months, placed in the slicing box, re-scanned in the 3 T magnetic resonance (MR) scanner and sliced into centimeter-thick slices. Postmortem in situ MR images (MRIs) are co-registered with 1 cm-thick brain slices to facilitate MRI-pathology correlations. All brain slices are photographed and brain white-matter lesions are identified. The spinal cord is cut into 2 cm segments. Alternate segments are fixed in 4% paraformaldehyde or rapidly frozen. The rapid procurement of postmortem MS tissues allows pathological and molecular analyses of MS brains and spinal cords and pathological correlations of brain MRI abnormalities. The quality of these rapidly-processed postmortem tissues (usually within 6 h of death) is of great value to MS research and has resulted in many high-impact discoveries.

Multiple sclerosis is an inflammatory demyelinating disease with no cure. Analysis of brain tissue provides important clues to understanding the pathogenesis of the disease. Here we discuss the methodology and downstream analysis of MS brain tissue collected through a unique rapid autopsy program in operation at the Cleveland Clinic.

多发性硬化患者综合解剖计划

We describe a rapid tissue donation program for individuals with multiple sclerosis (MS) that requires scientists and technicians to be on-call 24/7, 365 ...

高分辨率结构磁共振人类皮质下的成像

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