Neuromodulation is the science of how electrical, chemical, and mechanical interventions can modulate nervous system activity – the ultimate goal being to normalize brain activity and ultimately alleviate symptoms.
Today, it is quickly establishing itself as one of the most revolutionary areas of medicine and can be divided into two general categories: invasive, or non-invasive.
Two examples of invasive surgery are deep brain stimulation and vagal nerve stimulation, both of which involve the implantation of a small surgical electrode to alleviate symptoms of various diseases (Parkinson's, refractory depression).
These methods have shown promise, but the need for noninvasive approaches has spurred development efforts.
Two major modalities in the area of noninvasive brain stimulation are transcranial magnetic stimulation (TMS) and transcranial direct current stimulation (tDCS). TMS is FDA approved for use in treating refractory depression and migraines, and tDCS has shown promise for being used to treat depression.