Abstract: The circadian rhythm is an endogenous ~24-hour timing system that regulates various cognitive functions. Cognitive performance is typically impaired during the circadian trough and improves during the peak, and distinct cognitive domains exhibit unique temporal patterns. Existing research often fails to differentiate the underlying driving mechanisms, faces difficulties in a systematic explanation of the specific regulation of different cognitive functions, and lacks relevant neurophysiological evidence. This article aims to distinguish circadian effects driven by different mechanisms, explore their differential impacts on cognitive functions, and elucidate their specificity from a neurobiological perspective. Future research should develop computational neural models that incorporate multimodal data and individual differences, formulate light intervention strategies based on key time windows, and combine techniques such as temporal interference electrical stimulation to reveal the causal mechanisms linking rhythm to cognition, ultimately to develop precise cognitive preservation interventions for populations with circadian rhythm disorders.

Key words: circadian rhythm, two-process model of sleep-wake regulation, cognitive function