How lights affect the circadian rhythm in sleep-awake circle

Biological neurons receive a variety of external physical stimuli that are encoded in the nervous system to regulate the circadian rhythm in animals. Most types of nonlinear circuits are effective for exploring the dynamics and biophysical properties in biological neurons by analyzing the sampled time series for output voltage. To explore the impact of light on the homeostatic regulation of sleep-wake cycle, this paper proposes an enhanced neuron model that incorporates photocurrent activation, aiming to study the fundamental principles governing the sleep-wake cycle. In this paper, the frequency and intensity of external illumination are carefully adjusted to explore the occurrence of the firing modes in this light-sensitive neuron. The numerical results suggest that the circadian rhythm system can be impaired by continuous exposure to strong and high-frequency light. Additionally, an appropriate fine-tuning of the coupling strength between neurons can further optimize the response of a neural network to external light signals. These results provide insights into the regulation of light on circadian rhythm, and thus appropriate electromagnetic radiation can be applied to prevent and treat the sleep disorders.