Neural principles of the interaction between post-stroke depression and motor rehabilitation after stroke

卒中后抑郁（PSD）是卒中后的常见后果，约30%的患者受其影响。PSD通常与不良的运动预后和恢复有关。先前的研究表明，PSD的诊断可以基于情绪（快感缺乏）和动机症状（冷漠，疲劳）。迄今为止，这两种症状背后的神经网络变化在很大程度上仍然未知。本项目旨在确定卒中后情感症状与运动缺陷之间相互作用的神经关联及其对运动恢复的影响。该项目进一步解决了不同的PSD症状（情绪，动机）是否与中风后的运动网络有不同的关系。为此，本项目包括三项研究，包括对PSD和运动功能的行为评估，以及功能性磁共振成像（fMRI）和弥散张量成像（DTI）。实验组包括有或没有PSD和/或运动缺陷的中风患者，年龄匹配的健康受试者和没有任何中风证据的重度抑郁症患者。研究1旨在检测急性卒中患者情感和运动脑网络的功能连通性（使用静息状态fMRI）和结构连通性（使用DTI参数）。功能失调的互动和中断的连接将通过与健康受试者的比较来测试。此外，将研究情感网络和运动网络之间的特定功能障碍和关联，并与重度抑郁症患者进行对比，以弄清抑郁症和中风损害对神经网络的影响。在单个患者的水平上，使用多变量模式分类测试急性卒中后网络变化和慢性期运动预后的预测价值。研究2对脑卒中后慢性期情绪加工与运动行为的关系进行了更详细的实验研究。为此，fMRI运动任务和情绪处理任务被用来检查通常参与情绪处理和运动计划和执行的大脑区域之间的相互作用。同样，PSD对这些网络相互作用的影响将通过与健康受试者和重度抑郁症患者的比较来检验。有效连通性的变化将使用动态因果模型（DCM）进行测试。研究3以健康受试者和重度抑郁症患者为对照，检验了动机激励对基底节区慢性脑卒中患者伴有PSD（或冷漠）动机症状的后续运动表现的影响。本研究使用DCM测试将激励动机转化为运动努力的区域相互作用是否反映了动机减少对脑卒中患者运动恢复的负面影响。

Post-stroke depression (PSD) represents a common consequence of stroke that affects about 30% of the patients. PSD is frequently associated with poor motor outcome and recovery. Previous studies showed that the diagnosis of PSD can be based on both, emotional (anhedonia) and motivational symptoms (apathy, fatigue). To date, the changes in neural networks underlying each of the two symptoms remain largely unknown. This project aims at identifying neural correlates of the interaction between affective symptoms and motor deficits after stroke and their influence on motor recovery. The project further addresses the question whether different PSD symptoms (emotional, motivational) are differentially related to motor networks after stroke. To this end, the project includes three studies with behavioral assessments of PSD and motor function as well as functional magnetic resonance imaging (fMRI) and diffusion tensor imaging (DTI). Experimental groups consist of stroke patients with and without PSD and/or motor deficits, age-matched healthy subjects and patients with Major Depression without any evidence for stroke. Study 1 aims at examining the functional connectivity (using resting-state fMRI) and the structural connectivity (using DTI parameters) in affective and motor brain networks in acute stroke patients. Dysfunctional interactions and disrupted connectivity will be tested using comparisons with healthy subjects. Furthermore, specific dysfunctions and associations between affective and motor networks will be investigated in contrast to patients with Major Depression to disentangle the effects of depression and of the stroke lesion on neural networks. The predictive value of network changes following acute stroke and motor outcome at the chronic stage will be tested using multivariate pattern classification at the level of single patients. Study 2 represents a more detailed experiment on the relationship between emotion processing and motor behavior at the chronic stage post-stroke. To this end, an fMRI motor task and an emotion processing task are used to examine interactions between brain regions that are commonly engaged in emotion processing and motor planning and execution. Again, the effect of PSD on these network interactions will be tested by comparisons with healthy subjects and patients with Major Depression. Changes in effective connectivity will be tested using Dynamic Causal Modeling (DCM). Study 3 tests the effect of motivational incentives on the subsequent motor performance in chronic stroke patients with basal ganglia lesions and motivational symptoms of PSD (or apathy) in contrast to healthy subjects and patients with Major depression. This study uses DCM to test whether regional interactions translating incentive motivation into motor effort may reflect negative effects of reduced motivation on motor recovery in stroke patients.