Optimization of NIBS for Diabetic Neuropathy Neuropathic Pain

Inclusion Criteria: 1. Able to provide informed consent to participate in the study. 2. Subjects between 40 to 80 years old. 3. Having diabetic neuropathic pain, involving at least 1 foot, with existing pain for at least 6 months, and having pain on at least half the days in the past 6 months with an average of at least a 4 on a 0-10 VAS scale). 4. Having pain resistant to common analgesics and medications for first-line therapy of chronic pain such as Tylenol, Aspirin, Ibuprofen, Soma, Parafon Forte DCS, Zanaflex, Codeine, etc. 5. Must have the ability to feel pain as self-reported. Exclusion Criteria: 1. Subject is pregnant. 2. Contraindications to tDCS in conjunction with TUS, i.e. metallic implant in the brain or implanted brain medical devices 3. History of alcohol or drug abuse within the past 6 months as self-reported. 4. Use of carbamazepine within the past 6 months as self-reported. 5. Suffering from severe depression (with a PHQ 9 score of ≥ 10). 6. History of neurological disorders as self-reported. 7. History of unexplained fainting spells as self-reported. 8. History of severe head injury resulting in more than a momentary loss of consciousness as self-reported. 9. History of neurosurgery as self-reported. 10. Unstable pain (defined as pain intensities that vary by more than 4 points on 0-10 VAS scale over the 1-week period of trial run-in).