Neurobiological Mechanisms of Aging and Stress on Prospective Navigation

Inclusion Criteria: * adults 65-80 * U.S. citizens or permanent residents * who speak fluent English * willing to come to Georgia Tech to participate in group testing sessions. Exclusion Criteria: * Individuals will be carefully screened using IRB-approved procedures for safety contraindications to MRI and electrical shock stimulation * (e.g., metal or electrical implants, heart arrhythmia, or medication affecting the cardiovascular system \[e.g. beta-blockers\]). The purpose of this study is to investigate mechanisms of normally functioning memory, and memory-related changes in healthy aging. Thus, any confounding factors that may influence cognition, other than age, will be exclusionary. Potential participants that endorse any of the following conditions will be excluded from the study: * Epilepsy * Dementia * Parkinson's disease * history of stroke or seizure * psychiatric disorders * untreated depression or emotional conditions * Attention Deficit Disorder * Multiple Sclerosis * uncontrolled hyper- or hypo-tension * untreated Diabetes * Sickle Cell Anemia * regularly use illegal or psychoactive drugs (e.g., cocaine, alcohol abuse, etc). * Additionally, individuals scoring \< 3 on WAIS-R forward span, \< 2 on WAIS-R backward span, and failing to name more than 2 vegetable names will be excluded from the study. These exclusions will insure that persons with mild cognitive impairment or typical indications of clinical dementia will be not participate in the research.