Modulatory effect of trans-spinal magnetic intermittent theta burst stimulation on diaphragmatic activity following cervical spinal cord contusion in the rat

Background CONTEXT Magnetic stimulation can noninvasively modulate the neuronal excitability through different stimulatory patterns. Purpose The present study hypothesized that trans-spinal magnetic stimulation with intermittent theta burst stimulatory pattern can modulate respiratory motor outputs in a pre-clinical rat model of cervical spinal cord injury. Study design In vivo animal study. Methods The effect of trans-spinal magnetic intermittent theta burst stimulation on diaphragmatic activity was assessed in adult rats with unilateral cervical spinal cord contusion at 2 weeks postinjury. Results The results demonstrated that unilateral cervical spinal cord contusion significantly attenuated the inspiratory activity and motor evoked potential of the diaphragm. Trans-spinal magnetic intermittent theta burst stimulation significantly increased the inspiratory activity of the diaphragm in cervical spinal cord contused rats. Inspiratory bursting was also recruited by trans-spinal magnetic intermittent theta burst stimulation in the rats without diaphragmatic activity after cervical spinal cord injury. In addition, trans-spinal magnetic intermittent theta burst stimulation is associated with increases in oxygen consumption and carbon dioxide production. Conclusions These results suggest that trans-spinal magnetic intermittent theta burst stimulation can induce respiratory neuroplasticity. Clinical significance We propose that trans-spinal theta burst magnetic stimulation may be considered a potential rehabilitative strategy for improving the respiratory activity after cervical spinal cord injury. This will require future clinical study.