Pathways Relating Amnestic MCI to a Mild Traumatic Brain Injury History

Inclusion Criteria: 1. Active diagnosis of amnestic mild cognitive impairment 2. Presence of an mTBI history for the mTBI+ group; absence of an mTBI history for a control sample 3. Female and male subjects 4. All races/ethnicities 5. Age 55 years and older 6. Fluent in English Exclusion Criteria: 1. Mild traumatic brain injury within past year 2. Lifetime history of moderate or severe brain injury 3. Lifetime major neurologic syndromes (e.g., stroke, epilepsy, brain tumor) 4. Lifetime major cardiovascular conditions (e.g., heart attack, heart failure) 5. Current substance use disorder 6. Current major psychiatric disorders (e.g., major depressive disorder, bipolar disorder) 7. Current vision or hearing impairment that interferes with testing 8. Any electronic and or metallic implants in the skull or brain 9. Current medication use known to alter HD-tDCS reactivity