The role of neuromodulation to drive neural plasticity in stroke recovery: a narrative review

Stroke is one of the leading causes of death and adult disability globally, representing one of the highest burdens of disease worldwide. Recent advancements of neuromodulation techniques emerge as promising tools for enhancing stroke recovery, such as transcranial electric stimulation and transcranial magnetic stimulation, which can induce short- and long-term changes of synaptic excitability to restore the impaired functions in stroke patients. The review focuses on discussing the neuroplastic mechanisms of those brain stimulation techniques in stroke rehabilitation, also including some new options for neuromodulation which have great potential in stroke rehabilitation, such as optogenetic stimulation and environmental stimulation. In general, these techniques allow the excitation and synchronization of the neural activity after stroke, which could potentially induce long-term potentiation. As a result, the neuroplastic effect can lead to better functional connection in the brain network in assisting stroke recovery. Future directions include the clarification of the pathways of synaptic plasticity in the whole brain network following neuromodulation after stroke, and investigation of the different roles of distinctive cell populations in neural plasticity enhancement. Additional studies are essential for developing standard protocols in neuromodulation based on a better understanding of the molecular and cellular processes for the ultimate optimization of clinical efficacy.