Electrical Nerve Stimulation Induces Synaptic Plasticity in the Brain and the Spinal Cord: A Systematic Review

Abstract

This review compiles current literature on synaptic plasticity induced by electrical nerve stimulation (ENS) in nociceptive and somatosensory circuits of the central nervous system, emphasizing effects on the brain and spinal cord. Understanding the mechanisms of synaptic changes helps clarify ENS’s role in pain relief and the creation of experimental pain models. A systematic search of PubMed, Scopus, PEDro, SciELO, and Cochrane was conducted following PRISMA guidelines. The SYRCLE risk of bias tool was used to assess evidence quality. Inclusion criteria included ENS applied to peripheral nerves, detailed methodology, physiological synaptic measurements, and publication in English or Spanish. Out of 8094 studies, 85 met the criteria. ENS induced synaptic potentiation in 70 studies, depression in 7, and both in 8, depending on stimulation parameters and individual factors. Most research focused on spinal cord long-term potentiation. Few studies addressed ENS-related analgesia or supraspinal plasticity, highlighting the need for further research in these promising areas.