Neurological disorders including neurodegeneration (e.g., Alzheimer’s disease and Parkinson’s disease) and acute injuries (e.g., stroke and trau-matic brain injury) are the leading cause group of disability-adjusted life years and the second leading cause group of deaths. Different to other tissues, the adult brain retains only a very limited repair potential. Adult neurogenesis, the lifelong generation of new neurons, declines with age and in degenerative diseases, such as Alzheimer’s disease. Nevertheless, independently of age, the proliferation and migration of endogenous stem cells is stimulated after brain injuries and might be related to recovery processes (Adamczak et al., 2017). The limited number of endogenous stem cells during adulthood is one of the major limitations for an efcient regeneration of the injury affected brain regions. Therefore, the transplan-tation of neural stem or progenitor cells (NSCs/NPCs) is extensively stud-ied in mouse models and applied in first clinical trials with the aim to re-place dysfunctional or lost neural cells and thus to restore brain function. Long-term survival and differentiation of engrafted NSCs/NPCs, synaptic integration, and projections to distant brain regions, as well as behavioral improvements are promising observations in numerous pre-clinical stud-ies (Grade and Gotz, 2017). Transplanted stem cells initiate a complex series of potentially pro-regenerative processes with an individual time profile as it was shown by in vivo molecular imaging (Green et al., 2019).