Sound waves aimed at brain may quiet shaky hands

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Inclusion Criteria: * Experiment 1: Healthy Volunteers 1. Voluntary written informed consent of the participant or their legally authorized representative has been obtained prior to any screening procedures 2. Participants aged 18-55 years 3. Male of female 4. Good health with no history of serious mental illness or implanted metal 5. Willingness to adhere to the TUS and MRI study schedule 6. Willingness to avoid caffeine and alcohol intake for at least 2 h prior to the investigation * Experiment 2: ET Patients 1. Voluntary written informed consent of the participant or their legally authorized representative has been obtained prior to any screening procedures 2. Participants aged 18-75 years 3. Male of female 4. Diagnosis of ET as confirmed from clinical history and examination by a movement disorder neurologist 5. Willingness to adhere to the TUS and MRI study schedule 6. Willingness to avoid caffeine and alcohol intake for at least 2 h prior to the investigation Exclusion Criteria: * Experiment 1: Healthy volunteers 1. Currently taking any psychotropic medication 2. Any head trauma resulting in loss of consciousness 3. Diagnosed with a serious mental illness 4. Alcohol or substance abuse or dependence (other than tobacco) in the past week 5. Currently in treatment for a psychiatric condition 6. Pregnancy (a test will be scheduled by the research team) 7. Personal or family history of seizures or epilepsy 8. Claustrophobia or inability to stay still in the MR scanner environment 9. Any metal in the body that is not MRI-compatible 10. Serious history of migraines 11. Hair in dreadlocks, braids, or weave (not possible to position ultrasound transducer) 12. orthopedic forearm or hand problems 13. Inability to adhere to the experimental schedule. * Experiment 2: ET Patients 1. Currently taking any psychotropic medication 2. Implanted with a non-MRI compatible medical device 3. History of thalamotomy 4. Skin lesions at stimulation site 5. Peripheral neuropathy 6. neurologic exam not consistent with ET 7. Any head trauma resulting in loss of consciousness 8. Diagnosed with a serious mental illness 9. Alcohol or substance abuse or dependence (other than tobacco) in the past week 10. alcohol or caffeine consumption within 12 hours of study enrollment. 11. Currently in treatment for a psychiatric condition 12. Pregnancy (scheduled test) 13. Personal or family history of seizures or epilepsy 14. Claustrophobia or inability to stay still in the MR scanner environment 15. Any metal in the body that is not MRI-compatible 16. Serious history of migraines 17. Hair in dreadlocks, braids, or weave 18. orthopedic forearm or hand problems 19. Inability to adhere to the experimental schedule.