Closed-Loop Brain Stimulation as a Potential Intervention for Cognitive Decline

Inclusion Criteria: * Older adults 1. Ages between 60 to 90 years 2. Good general health 3. Normal or corrected vision 4. Completed elementary school education or able to understand middle school level experiment instructions 5. Self reports cognitive complaints * Cognitively normal young adults 1. Ages between 18 to 35 years 2. Good general health 3. Normal or corrected vision 4. Completed elementary school education or able to understand middle school level experiment instructions Exclusion Criteria: 1. Self-report of neurological or psychiatric diseases that could be contraindicated for TMS (e.g., personal history of epilepsy/seizure brain damage, history of fainting, bipolar disorder, schizophrenia, current substance use disorder, etc.). 2. Medications that elevate seizure threshold (e.g., stimulant medication, high dose bupropion). 3. Factors hindering EEG acquisition and rTMS delivery (e.g., skin infection, wounds, dermatitis, unable to access the scalp of the participant (e.g., unremovable wig). 4. Current participation in amyloid infusion treatment for Alzheimer's disease. 5. Do not have the capacity to provide informed consent and does not have a Legally Authorized Representative. 6. Resting motor threshold below the power limit in the laboratory. (Will be check on the first visit)