Transcranial magnetic stimulation

Understanding cortical connections to muscles is a key feature of assessment, diagnosis, and treatment in musculoskeletal physiotherapy. Since the 1880s, researchers have been exploring the organization and structure of the primary motor cortex using electrical stimulation. These investigations were initially performed in neurosurgical patients in whom it was possible to directly stimulate exposed nervous system tissue. In the late twentieth century, Merton and Morton advanced the field when they successfully elicited activation of the primary motor cortex using noninvasive electrical stimulation applied over the skull. Although still used in some settings today, the stimulus intensity required to overcome the resistance of the skull with this technique is high, resulting in pain and discomfort. This limitation was overcome with the development of transcranial magnetic stimulation (TMS) by Barker, Jailnous, and Freeston in 1985.