Non-invasive brain stimulation (TMS) to probe neural correlates of gait retraining in lower limb muscles 

 

To understand how stroke and stroke gait training modify cortical and corticospinal circuit physiology,  we use transcranial magnetic stimulation (TMS) to assess corticospinal excitability of lower limb muscles. A majority of previous TMS literature focuses on upper limb neuromotor control. To enhance the rigor of lower limb TMS, our lab has conducted studies to evaluate the influence of methodological factors such as activation state of the target and non-target (antagonist, agonist, coactivation) muscles and posture (seated, standing) on TMS-derived evoked responses in ankle muscles of able-bodied and post-stroke individuals. We also paired TMS with peripheral nerve stimulation to probe intervening connections between the motor cortex and spinal lower motor neurons. Ongoing NIH-funded projects in our lab are utilizing TMS-based neurophysiologic outcomes to evaluate the magnitude and time-course of gait training-induced neuroplasticity in people with chronic post-stroke hemiparesis.