Some patients with brain tumors will have different degrees of cognitive dysfunction after cranial radiotherapy[1,2]。 Radiation-induced loss of neural stem cells and impaired neurogenesis are one of the mechanisms of radiation-induced cognitive dysfunction[3]。 Implementation of stem cell transplantation is expected to improve radiation-induced cognitive dysfunction[4,5]。 However, it is unclear whether neurons differentiated from stem cells transplanted into the brain can integrate into existing neural circuits. The genes encoding glycoprotein (G protein) and envelope protein of rabies virus are replaced by fluorescent proteins such as GFP, mCherry and EnvA, respectively. Therefore, the virus specifically infects TVA-transfected neurons[6]。 In this study, neural stem cells were infected with lentivirus in vitro to express TVA, G protein and mCherry fluorescent protein, and then reverse transmonosynaptic neural tracing technique based on rabies virus was used[7]To observe the integration of neurons derived from transplanted neural stem cells into neural circuits.