Identification of brain structures and networks encoding pain, hyperalgesia, pain control and sympathetic function acutely after stroke. A voxel-based lesion-behavior – network mapping study of acute stroke patients

疼痛、痛觉过敏和疼痛控制机制在大脑中的编码尚不完全清楚。这同样适用于交感神经系统功能的编码。功能性磁共振成像（fMRI）研究结果的特异性，研究了健康受试者在重复短时间疼痛刺激后的大脑激活，最近受到了挑战，因为短时间疼痛刺激的非生理显著性。该项目将通过研究感觉（包括痛觉、痛觉过敏、定量心理物理学评估的疼痛控制）和交感神经功能障碍作为中风后2-7天的临床表型，在中枢重组过程发生之前，克服这一缺点。采用基于体素的病变-行为映射（VLBM）方法，对200例患者的脑结构核磁共振成像结果进行分析。由于最初描述的VLBM可能不足以检测单一的大脑病变，这些病变单独负责复杂的感觉行为（例如痛觉过敏或疼痛控制），因此分析将扩展到“行为-大脑网络”映射。这将通过使用主要来自AgeGain项目（Mainz数据）的匹配正常受试者的数据集来实现，该数据集提供了功能连接数据，并将允许我们评估个体局灶性脑病变作为脑网络种子的影响。来自个人的连接数据将在第二步中重叠。我们期望与不同表型相关的受影响网络的重叠程度高于局灶性脑病变本身。另一种方法是评估局灶性脑损伤对预定静息状态功能MRI连接（rs-fMRI）网络的影响。rs-fMRI扫描将与结构扫描一起获得。在这个项目的最后，我们将描述负责编码疼痛、痛觉过敏、疼痛控制和植物人行为的大脑网络。此外，这项研究的结果可能成为一项设想的纵向研究的基础，该研究揭示了脑网络病变的模式，这种模式可能导致中风后几个月由于不适应的大脑重组而导致慢性中风后疼痛。

The encoding of pain, hyperalgesia and pain control mechanisms in the brain is incompletely understood. The same applies for encoding of sympathetic nervous system function. The specificity of results of functional MRI (fMRI) studies, which investigated brain activation after repetitive short pain stimuli in healthy subjects, was recently challenged because of the non-physiological salience of the short-lasting pain stimuli. This project will overcome this shortcoming by investigating sensory (including pain perception, hyperalgesia, pain control assessed by quantitative psychophysics) and sympathetic dysfunction as a clinical phenotype 2-7 days after stroke before central reorganization processes take place. The behavior will be correlated to brain lesions in structural MRIs of ~200 patients by voxel-based lesion-behavior mapping (VLBM). Since the originally described VLBM might be not sufficient to detect single brain lesions, which alone are responsible for complex sensory behavior (e.g. hyperalgesia or pain control), the analysis will be extended to “behavioral–brain network” mapping. This will be achieved by making use of datasets of matched normal subjects mainly from the AgeGain project (Mainz data), which provides functional connectivity data and will allow us to assess the impact of individual focal brain lesions as seeds on brain networks. The connectivity data from individuals will be overlapped in a second step. We expect a higher overlap of the affected networks associated with a distinct phenotype than of the focal brain lesions themselves. Another approach will be to assess the impact of focal brain lesions on predefined resting state functional MRI connectivity (rs-fMRI) networks. The rs-fMRI scans will be obtained together with the structural scans. At the end of this project we will describe the brain networks that are responsible for encoding of pain, hyperalgesia, pain control and vegetative behavior. Moreover, the results of this study might become the basis for an envisaged longitudinal study uncovering the patterns of brain network lesions which can lead to chronic post-stroke pain months after stroke due to maladaptive brain reorganization.