In situ in vivo and ex vivo study of the aging human brain: towards creating an MRI and histology brain template averaging 100 cases

对正常衰老的大脑的研究，是利用人们死后捐献给科学研究的大脑来完成的，被称为大脑的离体研究。对离体大脑的微观研究使我们能够了解任何给定区域的结构，这是一些神经科学研究的基础。然而，我们不能用显微镜研究健康人的大脑（在体内）。研究活体大脑的一种方法是磁共振成像（MRI），它使用功能强大的机器，提供非常高的图像分辨率（7台特斯拉MRI扫描仪）。单独使用MRI的缺点是不确定哪些细胞对MRI上给定的对比度（颜色）负责。为了解决这个问题，我们首先使用MRI研究离体大脑（在我们提议的项目中，我们将使用我们大学解剖系捐赠者的大脑），然后使用显微镜。最后，我们可以使用供体以前的（体内）MRI扫描，通过他们的医疗档案，将我们的离体MRI结果转化为体内MRI结果。我们的研究计划将评估四种不同的保存大脑的方法，以获得更好的MRI结果，并将这些结果与脑库采用的最常用的保存方法进行比较，脑库采用的方法是将大脑取出，并在装满液体（在MRI扫描上不会产生颜色的特殊液体）的塑料容器中对头部外的大脑（非原位）进行MRI扫描。对大脑进行非原位扫描会导致组织变形，使其与相应的组织学切片和体内扫描的比较复杂化。我们的计划建议采用标准程序来保存和扫描离体和原位的大脑，改进与标本组织学和活体参与者扫描的比较研究。然后，我们的扫描结果将用于创建一个具有组织学相关性的平均MRI离体原位模板，这将是开源的，并可供神经科学界使用。

The study of the normal aging brain is accomplished using brains that people donate to science after they die, which is called ex vivo study of the brain. The microscopic study of ex vivo brains allows to understand the structure of any given region, which is the basis of several neuroscientific research studies. However, we cannot study the brain of healthy living people (in vivo) using microscopy. One method to study the brain in vivo is magnetic resonance imaging (MRI) using powerful machines that provide very high image resolution (7 Tesla MRI scanners). The downside of using MRI alone is the lack of certainty of which cells are responsible for a given contrast (color) on the MRI. To solve this, we study first the brain ex vivo using MRI (in our proposed program we will use the brain of donors of the Anatomy Department of our university), and then microscopy. Finally, we can use previous (in vivo) MRI scans of donors, available through their medical files, to translate our ex vivo MRI findings, to in vivo MRI findings. Our research program will assess four different ways to conserve the brain inside the head for better MRI results and will compare those results against the most utilized way of conservation employed by brain banks, which remove the brains and force the MRI scanning of the brains outside the head (ex situ) inside plastic containers filled with fluid (special fluid that does not produce a color on the MRI scan). Scanning brains ex situ introduces deformations of the tissue that complicate its comparison with the corresponding histology slices and with in vivo scans. Our program proposes the deployment of standard procedures to conserve and scan brains ex vivo and in situ, improving the comparative study with histology of the specimens, and with scans of living participants. Our scans will be then used to create an average MRI ex vivo-in situ template with histological correlates, which will be open-source and available to the neuroscientific community.