Exergames (EG) are interactive video games that require physical activity and use gamification to make exercise more engaging. EG interventions have shown various benefits for older adults, such as improved mental health, quality of life, and reduced fall risk. Enhanced cognition is thought to drive these benefits. This review aimed to identify neural correlates underlying cognitive improvements in healthy older adults and those with neurocognitive disorders. We systematically searched major databases and included 13 studies from 2,095 records. Findings revealed that EG interventions led to structural brain changes and improved functional connectivity in healthy adults, Parkinson patients, and those with mild cognitive impairment (MCI). Increased activity in the frontal, temporal, and precuneus regions during rest was specific to adults with neurocognitive disorders. Neuroplastic changes, such as elevated BDNF levels and increased neurovascular coupling, were observed in both groups. However, methodological limitations in some studies highlight the need for further high-quality research.