The dystonias are a relatively rare group of movement disorders that often prove difficult to treat effectively. In recent years, advances in our understanding of genetics has allowed identification of a number of causative mutations, as well as acquired aetiologies including peri-natal insults. However, despite this progress, pharmacological treatment options have remained limited and patients may still acquire considerable disability as a consequence of the disease. In contrast, the use of deep brain stimulation (DBS), available since the late 1980s, has become more widespread and now has established efficacy in a range of movement disorders, although its exact mode of action remains unclear. A detailed understanding of mechanism of DBS would clearly have significant benefits including refining patient selection and minimising the risk of side effects. Rather uniquely, the procedure itself may offers unparalleled opportunities for direct electrophysiological recordings of brain activity which in turn may allow insights into the pathophysiology underlying movement disorders, and also the mechanism by which it has its effects.