* INCLUSION CRITERIA:
Healthy research volunteers and adult patients with cervical dystonia will be eligible for the study.
1. Adult patients with cervical dystonia will have clinically documented cervical dystonia (focal cervical or segmental with neck involvement)established by history and physical/neurological examination.
--Cervical dystonia patients must not have had received botulinum toxin injections into neck muscles for at least about 10 weeks at time of study participation
2. Healthy volunteers will be healthy subjects without neurological or psychiatric disorders (except for stable mild anxiety or stable mild depression) established by history and physical/neurological examination.
3. All participants will be at least 18 years of age. There is no maximum age limit.
4. Participants must be able to abstain from tobacco or nicotine replacement for at least 3 days prior to PET scan if participating in both MRI and PET scanning..
5. Participants must be able to abstain from caffeine for at least 24 hours prior to PET scan if participating in both MRI and PET scanning.
6. Participants must be able to fast for 3 hours before PET scan if participanting in both MRI and PET scanning.
EXCLUSION CRITERIA:
1. Subjects who are incapable of giving informed consent.
2. Employees of NINDS
3. Pregnant or breastfeeding women. Aside from history obtained at the screening, pregnancy status in women with childbearing potential is also established by urine pregnancy testing no more than 24 hours before each MRI and PET scan session.
4. Subjects with past or present medical history of (a) neurological disorders, such as stroke, movement disorders (other than cervical dystonia in the patient group), brain tumors, traumatic brain injury with loss of consciousness lasting more than a few seconds, ataxias, myopathies, myasthenia gravis, demyelinating diseases, alcoholism, drug dependence; (b) psychiatric disorders besides stable mild anxiety or stable mild depression, such as schizophrenia, major depressive and/or bipolar disorder, obsessive-compulsive disorder; (c) ventricular arrhythmias, renal and hepatic insufficiency, vascular headache, or carcinoid syndrome.
5. Abnormalities in neurological examination other what is typically associated with cervical dystonia, or any abnormalities in neurological examination in healthy volunteers.
6. Subjects who are currently taking oral medications known to affect muscarinic acetylcholine receptor binding in the central nervous system. Of note, some over-the counter-medications are known to affect muscarinic acetylcholine receptor binding. Subjects who use medications known to affect muscarinic acetylcholine receptor binding, such as first generation antihistamines for common cold and allergy symptoms and sleep aids for insomnia, occasionally on an as needed basis may be enrolled in this study. Furthermore, these as needed medications should be paused for at least 3 days before PET scanning. This three-day period is equivalent to about 4 to 5 half lives for these medications. In addition, subjects who use topical antimuscarinic medications, such as eye drops for glaucoma and inhalers, may be enrolled in this study because topical antimuscarinic medications have negligible systemic bioavailability. Subjects who have contraindications to MRI, ferromagnetic objects in their bodies (e.g., implanted stimulators including deep brain stimulation, aneurysm clips, prosthesis, artificial heart valves, etc.) that cannot be removed for the purpose of study participation.
7. Subjects who have claustrophobia.
8. Subjects who are unable to lie comfortably on their back for about one hour for MRI scanning (and about two hours for PET scanning if participating in both MRI and PET scanning).
9. Subjects with any radiation exposure in the past year that, together with the research PET scan, would exceed the NIH Radiation Safety Committee s annual limit (5 rem) if participating in both MRI and PET scanning.
10. Cervical dystonia patients who have cervical dystonia associated with trauma
