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

This study is testing whether light flickering at a specific frequency (40 Hz gamma light) can influence brain activity in cognitively healthy older adults. It aims to understand if this type of sensory stimulation might benefit brain function and be used as a future tool to protect against cognitive decline. **You may be eligible if...** - You are over 55 years old - You have normal cognitive function (confirmed by a standard screening test) - You have normal or corrected-to-normal vision - You have not used medications that affect cognition (e.g., benzodiazepines) - You have no history of stroke, epilepsy, migraine, or depression **You may NOT be eligible if...** - You enrolled in another cognitive enhancement study in the past 2 months - You have had cancer, autoimmune disease, or another condition affecting cognition - You are pregnant or planning to become pregnant Talk to your doctor to see if this trial is right for you.