Individualized Modeling and Synchronization of Circadian Oscillators with Light-Dark Cycle

Sleep behaviors, including daily spontaneous sleep duration, onset, and recovery sleep duration after sleep deprivation, vary between individuals. Lighting impacts on circadian oscillators and sleep-wake cycle, as well as their synchronization with light-dark cycles, also show significant interindividual variations. In this paper, we investigate the dynamics of circadian oscillators and sleep of regular, long, and short sleepers under light-dark cycles by using a two-process dynamical system model, whose parameters of each sleeper type are determined by an evolutionary algorithm to fit experimental measurements of daily sleep duration, sleep onset and wake onset times. These models are further developed to simulate recovery sleep and wake following acute sleep deprivation, and then validated by existing experimental results. Recovery after jet-lag is finally discussed and compared among different sleeper types. Numerical simulation demonstrates the two-process dynamical model with well-defined parameters accurately replicates sleep-wake cycles of different individuals. Case studies illustrate the interindividual differences in synchronization of circadian oscillators and recovery from jet-lag under light-dark cycles.