Transcranial Electrical Stimulation for Cervical Dystonia

Primary Cervical Dystonia Inclusion Criteria: * Right-handed * On a stable dose of all medications used to treat dystonia for the month previous to enrollment * No botox injections in the 10 weeks previous to enrollment Exclusion Criteria: * Any contraindication to MRI scanning, tES, or TMS (e.g pregnancy, history of seizures, significant systemic medical conditions, untreated psychiatric or neurological conditions) * Evidence on neurological exam of any potentially confounding neurological disorder * Evidence of significant cognitive impairment * Patients with dystonia symptoms beginning prior to the age of 18 will be excluded * Patients with secondary dystonia resulting from medications or that are part of another neurological disorder (e.g. Parkinson's disease) will be excluded * Medication that might predispose the subject to seizures Healthy Controls Inclusion Criteria: \- Right-handed Exclusion Criteria: * Any contraindication to MRI scanning, tES, or TMS (e.g pregnancy, history of seizures, significant systemic medical conditions, untreated psychiatric or neurological conditions) * Evidence on neurological exam of any potentially confounding neurological disorder * Evidence of significant cognitive impairment * Medication that might predispose the subject to seizures