Effectiveness of Light for Enhancement of Cognition by Transcranial Repeated Application (ELECTRA)

Inclusion Criteria: * Age: 18-25 or 65-85 * Women of child-bearing potential, must use a double-barrier method for birth control (e.g. condoms with spermicide) if sexually active during the study and for 30 days post treatment of any kind. * Subject Informed Consent obtained in writing in compliance with local regulations prior to enrollment into this study. * The subject (and caregiver, if applicable) is willing to participate in this study for at least 12 weeks. Exclusion Criteria: * Inability to speak or read English (necessary for cognitive testing software use). * Pregnancy or lactation * History of stroke or traumatic brain injury * Substance dependence or abuse in the past 6 months * Diagnosis with major psychiatric disease (Psychotic disorder or psychotic episode, bipolar affective disorder) * Diagnosed with a neurodevelopmental condition (autism or ADHD) * A traumatic event that resulted in PTSD * Any unstable medical illness (defined as any medical illness which has not been well-controlled with standard-of-care medications) * A significant skin condition (i.e., hemangioma, scleroderma, rash, open wound) or medical implant (e.g. metal plate, implantable shunt or valve) on the head. * Inability to understand or participate in the consent and performance of the study. * Those with Parkinson's Disease, End Stage Renal Disease, and/or End Stage Liver Disease