Effects and Mechanisms of Temporal Interference Brain Stimulation on Memory Function in Preclinical Alzheimer's Disease

Inclusion Criteria: * Individuals recruited from neurology memory clinics or communities. * Age between 60 and 80 years old, inclusive; no gender limitation. * Right-handed. * Cognitive function test results within normal range after age, gender, and education-level adjustment, OR mild cognitive impairment not yet meeting diagnostic criteria for Mild Cognitive Impairment (MCI), OR only subjective cognitive decline. * Individuals classified as preclinical AD based on the revised 2024 AD diagnostic and staging criteria (i.e., cognitively normal with positive plasma p-tau217 or positive Aβ PET). * Full understanding of the study, voluntary participation, and provision of written informed consent approved by the Ethics Committee. Exclusion Criteria: * Past or present neurological diseases (e.g., stroke, epilepsy, Parkinson's disease, multiple sclerosis). * Psychiatric disorders such as severe depression or severe anxiety. * Systemic diseases causing cognitive decline (e.g., severe thyroid dysfunction, severe liver or kidney disease, severe nutritional deficiencies). * Currently taking medications that may affect cognitive function (e.g., anticholinergics, benzodiazepines, antipsychotics) that cannot be discontinued or adjusted. * Other factors leading to cognitive decline that are not AD-related. * Contraindications for MRI scans, such as claustrophobia, implanted metallic devices (e.g., pacemakers, cochlear implants, aneurysm clips), or history of head injury with retained metal fragments.