Quadripulse stimulation--a new patterned rTMS.

A new patterned repetitive transcranial magnetic stimulation (rTMS) protocol, quadripulse stimulation (QPS), can produce a broad range of motor cortical plasticity ranging from MEP suppression to MEP facilitation depending on the interval of the pulses within a burst. In addition to inducing lasting cortical plastic changes, QPS can also be used to evaluate priming effects: when used as a priming stimulation, which does not induce an LTP- or LTD-like phenomena itself, it can nevertheless change the threshold for LTP- or LTD-like plasticity caused by a consecutive stimulation. This enables us to examine metaplasticity theory in more details in humans. Another application of QPS might be to induce symptomatic relief in patients with neurological or psychiatric disorders, such as Parkinson's disease, depression, or intractable pain.