Healthy controls refer to individuals who do not have the medical condition or disorder being studied in a research project. They are typically used as a baseline comparison group to assess factors such as brain activity, cognitive function, or genetic markers in individuals with a specific disease or condition. Healthy controls are usually matched to the experimental group based on factors such as age, gender, and other relevant demographics to ensure that any observed differences are due to the condition being studied and not other variables. Studying healthy controls can help researchers gain a better understanding of the mechanisms underlying diseases and disorders, as well as identify potential biomarkers or treatment targets.