Inclusion Criteria:  Diagnosis of possible or probable ADRD according to the National Institute of Aging - Alzheimer's Association diagnostic criteria Clinically meaningful apathy for at least four weeks, clinically diagnosed according to 2018 Apathy Diagnostic Criteria or defined as Neuropsychiatric Inventory (NPI-Q) apathy score equal or above 4 (i.e., severity of 'moderate' or greater and caregiver distress 'mild' or greater). Stable doses of cholinesterase inhibitors, memantine and other psychotropic medications for at least three months.  Exclusion Criteria:  Unstable medical conditions History of epilepsy Metallic objects in the brain Diagnosis of major depression and/or a score higher than 18 on the Cornell Scale for Depression in Dementia