MRI Study of High Definition Transcranial Electrical Stimulation in Chronic Tinnitus (MRI HDtES-T)

Inclusion Criteria: 1. Ages between 18 and 75 2. Race/ethnicity: all races and ethnic groups 3. Sex/Gender: all 4. Capacity to provide informed consent 5. Subjective tinnitus symptoms confirmed by patient self report meeting the following criteria: 1. Present for at least one year prior to start of study 2. Present (can be heard when consciously attended to) \>50% of awake time 3. Intrudes (is heard even when attempting to ignore/mask) \>10% of awake time 6. Has discussed tinnitus symptoms with clinician (i.e., physician, audiologist) to confirm low/no likelihood of physical or neurological origin of tinnitus symptoms (e.g., acoustic neuroma, Meniere's Disease, etc.), confirmed by patient self-report 7. Stable standard or no pharmacological treatment regimen for tinnitus with no change in treatment 6 weeks prior to study start Exclusion Criteria: 1. Ages below 18 (neurobiology is quite different in children vs. adults) 2. Ages above 75 (cortical excitability changes with age) 3. Tinnitus symptoms with known medial origin, including: 1. Meniere's disease 2. Pulsatile tinnitus 3. Acoustic neuroma 4. Spontaneous optoacoustic emissions 5. Any other known medical origin 4. Severe mood disorder (major depression or anxiety) 5. Diagnosis of any medical condition potentially affecting brain function, including: 1. neuropsychiatric or mental disorders (bipolar, post-traumatic stress disorder, etc.) 2. severe mood disorders (major depression or anxiety) 3. psychotic states or disorders 4. developmental disorders 5. neurological disorders, including mild cognitive impairment 6. significant head injury 7. significant history of alcohol/substance abuse or dependence 8. active chronic pain condition (\>1 year duration) 9. other major medical conditions (e.g., cancer, stroke). 6. MRI contraindications: 1. metal or other implants that are not MR-safe 2. claustrophobia 3. pregnancy or suspected pregnancy 7. tDCS contraindications\*: 1. skin conditions or injuries on the scalp 2. hair extensions, wigs, braids, etc. that cannot be removed prior to the study 3. metal implants or pacemakers (also contraindicated for MRI) 8. Non-English speakers (due to written consent and questionnaires administered) 9. Significant history of alcohol/substance abuse or dependence within last 12 months 10. Neurostimulation or neuromodulation treatment longer than 20 minutes within the past 3 months 11. Current medication use potentially affecting brain function, including decongestants, antihistamines, benzodiazepines or other anticonvulsants, or anti-psychotics.