Cognitive reserve refers to the brain's ability to maintain normal cognitive function despite damage or disease. It is believed to result from complex interactions between genetic, developmental, environmental, and lifestyle factors. Individuals with high cognitive reserve may exhibit better cognitive performance and be less likely to develop symptoms of cognitive decline, such as dementia, compared to individuals with lower cognitive reserve. Research in this area focuses on understanding the underlying mechanisms of cognitive reserve and how it can be enhanced or preserved through various interventions, such as education, cognitive training, physical exercise, and social engagement.