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

• Applicant: Professor Dr. Christian Grefkes-Hermann, since 8/2022
• Subject Area: Clinical Neurology; Neurosurgery and Neuroradiology
• Term: from 2016 to 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 310098283

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.

• DFG Programme: Research Grants
• Ehemalige Antragstellerin: Dr. Anne Kathrin Rehme, until 7/2022