Linking multimodal MRI metrics and their changes to histological underpinnings

使用磁共振成像（MRI）的非侵入性脑成像在理解大脑的结构和功能方面取得了重大进展。现在可以从扩散和T1成像中获得大量参数，从而以高分辨率观察白色和灰质的结构。然而，即使在体内可能的最佳分辨率下，来自每个体素的信号也对应于数千个细胞和亚细胞实体。脑组织的精确组成解释了磁共振成像中所见的白色和灰质的特性差异，但这一点尚未完全了解。此外，我们早就知道大脑是可塑的，它可以在我们的一生中自我重组，这些变化可以通过现代MRI技术观察到。然而，在MRI上观察到的重组模式背后的组织学基础在很大程度上仍然未知。已知慢性疼痛会引起这种在MRI上可见的形态学变化。这里提出的研究项目将集中在诱导慢性疼痛的动物模型，以确定区域的白色和灰质，重组最。随后，将采集大脑的组织切片，以标记不同的脑细胞成分，以识别存在哪些细胞类型，然后量化慢性疼痛诱导的变化，并将这些变化与MRI中观察到的变化相关联。主要目标是，当我们观察到MRI信号的变化时，发现解释这些差异的真实的细胞变化是什么。

Non-invasive brain imaging using magnetic resonance imaging (MRI) has enabled major advances in understanding the structure and function of the brain. It is now possible to obtain a large number of parameters derived from diffusion and T1 imaging allowing the structure of white and gray matter to be observed with high resolution. However, even at the best resolution possible in vivo, the signal from each voxel corresponds to several thousand cells and subcellular entities. The precise composition of brain tissue that explains the differences in the properties of white and gray matter as seen on MRIs is not yet fully understood. In addition, we have long known that the brain is plastic and that it can reorganize itself throughout our lives, and these changes are observable with modern MRI techniques. However, the histologic foundations underlying the patterns of reorganization observable on MRI remain largely unknown. Chronic pain is known to induce this type of morphological change that can be seen on MRI. The research project presented here will focus on inducing chronic pain in an animal model in order to identify the regions in white and gray matter that reorganize the most. Subsequently, histological sections of the brain will be taken in order to mark different brain cell components to identify which cell types are present, and then to quantify the changes induced by chronic pain and to correlate these with the changes observed in MRI. The main goal is to find, when we observe a change in the signal obtained by MRI, what are the real cellular changes explaining these differences.