Effects of Endogenous Gamma Light Stimulation on Brain Oscillations in Cognitively-normal Older Adults

Inclusion Criteria: * 1\. Age over 55 years old. * 2\. The Cognitive Abilities Screening Instrument (CASI) score is within normal ranges adjusted for age and education. * 3\. Participants have no history of severe neurological or psychiatric disorders (such as stroke, epilepsy, depression, migraine, etc.) that could affect cognitive function. * 4\. Participants have not used drugs that may affect cognitive function (e.g., benzodiazepines, anticholinergic medications, etc.). * 5\. Participants with normal or corrected vision (e.g., glasses or contact lenses) to normal levels. * 6\. Voluntary to sign the Informed Consent Form. Exclusion Criteria: * 1\. Participants enrolled in any cognitive enhancement study within the past two months. * 2\. Participants with a history of disease that could affect cognitive function (e.g., cancer, autoimmune diseases, etc.). * 3\. Pregnant, or planning to become pregnant.