cTBS enhanced synaptic plasticity in the affected and unaffected motor cortex after cerebral ischemia via...

Continuous theta burst stimulation (cTBS), as a neuromodulation mode, has a long after-effect and a short stimulation time, which can significantly improve the cost-effectiveness. However, the application of cTBS is limited due to the heterogeneity of its effects on cortical excitability. Animal experiments provide the possibility to explore the neurobiological mechanism of cTBS. In this study, post-stroke rats were given cTBS once daily on the unaffected hemisphere. Rats were randomly divided into MCAO and cTBS groups. Each group was further divided into mild-medium stroke and large stroke subgroups according to magnetic resonance imaging and modified neurological severity score. The treatment began on day 4 after stroke and continued for 2 weeks. We found that cTBS could improve motor function in rats with mild-medium stroke and large stroke. cTBS increased the number of neurons and the activation of neurons in the bilateral motor cortex. The results of Golgi staining and MAP-2 staining suggested that cTBS promoted dendritic remodeling in the bilateral motor cortex regardless of the degree of injury. In addition, cTBS enhanced synaptic plasticity in bilateral motor cortex, including synaptic number, synaptic structure, and synaptic function. cTBS induced synapse regeneration via the astrocyte-mediated TSP1 pathway, but other mechanisms were involved in the functionalization of synapses. In conclusion, the present study demonstrated that cTBS had a significant effect on neuronal and synaptic plasticity in the bilateral motor cortex after cerebral ischemia.