How does DBS work?

Deep brain stimulation (DBS) produces striking effects in patients with various disorders including Parkinson's disease and dystonia, yet its precise mechanism of action is not clear. Because the clinical benefits of lesioning target structures such as the thalamus, globus pallidus and subthalamic nucleus appear to be similar to those achieved by chronic application of stimulation at these structures, it has been surmized that deep brain stimulation produces a functional inactivation or block of the target. This simplistic proposal has supporting and detracting evidence. In the present work we consider the mechanism of action of DBS and provide arguments for and against the stimulation or inhibition of target neural structures.