Priming Through Timing. Using Opposing Strategies to Enhance Motor Learning for Individuals With Parkinson's Disease

Inclusion Criteria: * Individuals with a diagnosis of Parkinson's Disease (made by movement disorders specialist) will be included in this study. Additional inclusion criteria include: self-reported ability to walk \~6 minutes overground as well as walk on a treadmill for a total of 10 minutes with rest breaks as needed, and be classified as Stage 2, or 3 on the Hoehn and Yahr Scale (Goetz et. al, 2004). Exclusion Criteria: * Exclusion criteria include Hoehn and Yahr Stages 1, 4, or 5, uncontrolled cardiorespiratory/metabolic disease (e.g., cardiac arrhythmia, uncontrolled hypertension or diabetes, orthostatic hypertension, chronic emphysema), or other neurological or orthopedic disorders that may affect walking. The investigators will also exclude participants with severe communication impairments, which could impede understanding of the purpose or procedures of the study or an inability to comply with experimental procedures.