When balance is perturbed, the brain must integrate sensory input across multiple joints and limbs to perceive body position and plan the appropriate muscle response. Findings from our lab demonstrate that stroke survivors have altered cortical responses and muscle activation patterns in response to a perturbation, but it is unknown whether these abnormal responses are related to impairments in whole-body motion perception. In neurotypical adults, whole-body motion perception thresholds vary across individuals, and in older adults, higher (i.e., worse) thresholds are associated with worse balance ability. This research seeks to identify the underlying neural correlates of whole body motion perception and the association to balance ability in neurotypical younger and older adults, and people who have had a stroke. Given increased risk of falls with aging that is further increased post-stroke, developing structural and functional biomarkers of somatosensory perception and balance function is necessary to identify individuals at risk for falls, and to advance development of effective, evidence-based rehabilitation interventions. Eligibility Adults 50-80 years old who have had an ischemic stroke > 6 months ago or adults without a stroke. ability to stand > 15 minutes and walk 10 meters with or without assistive device.