Linking multimodal MRI metrics and their changes to histological underpinnings

使用磁共振成像(MRI)的非侵入性脑成像使人们在了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成像获得大量参数，从而以高分辨率观察白质和灰质的结构。然而，即使在活体内以最好的分辨率，来自每个体素的信号也对应于数千个细胞和亚细胞实体。脑组织的确切组成解释了核磁共振成像上看到的白质和灰质属性的差异，目前还没有完全了解。此外，我们早就知道大脑是可塑性的，它可以在我们的生活中自我重组，这些变化可以通过现代核磁共振技术观察到。然而，在MRI上观察到的重组模式的组织学基础仍然很大程度上是未知的。慢性疼痛是已知引起这种类型的形态变化，可以在MRI上看到。这里提出的研究项目将专注于在动物模型中诱导慢性疼痛，以确定白质和灰质中重组最多的区域。随后，将对大脑进行组织切片，以标记不同的脑细胞成分，以确定存在哪些细胞类型，然后量化慢性疼痛引起的变化，并将这些变化与MRI观察到的变化相关联。我们的主要目标是发现，当我们观察到核磁共振信号的变化时，解释这些差异的真正细胞变化是什么。

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.