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PresentationsDesynchronization of the circadian rhythm and the sleep-wake cycle under the influence of fluctuations in external factorsSaratov State University, 83 Astrakhanskaya Street, Saratov, 410012 One of the tools for studying sleep and sleep-related phenomena is mathematical modeling. In this work, we use a model of an activating system [1], where the dynamics of excitation is modeled in terms of populations of neurons and their interactions. The elements responsible for sleep or wakefulness are the key neuromodulating nuclei, and the external force that causes a change in the activity of these areas are circadian and homeostatic processes, which are presented in the form of oscillators. The model also takes into account the sensitivity to light, which today is the main external factor that regulates our biological clock. In [2, 3], it was shown that the parameters responsible for the influence of other populations of neurons on the sleep centers Av and wakefulness Am, significantly affect the period of the homeostatic oscillator. Within the framework of this work, the task was set to investigate the behavior of the model under fluctuations from external influences. An expression for MHAT-wavelet was used to set the pulse shape. The simulated random process is close to the experimentally recorded ultradian oscillations of hormones. In normal mode, the duration of sleep is constant, the circadian phases are not shifted. With modulation up to 3%, variability of homeostatic markers is observed. At 4% modulation, a phase jump occurs and there is a desynchronization of the circadian and homeostatic processes. As the modulation depth is increased further, the effect is enhanced, and desynchronization with the light-dark cycle is added. The results of the study allow us to conclude that any factor that changes the period of the homeostatic oscillator can cause desynchronization in one form or another. In addition, there is a direct relationship between the force of impact and the degree of desynchronization. 1. S. Postnova, S. W. Lockley, and P. A. Robinson, “Sleep propensity under forced desynchrony in a model of arousal state dynamics,” Journal of biological rhythms 31(5), pp. 498–508, 2016. 2. Postnov D. E., Merkulova K. O., Postnova S. Desynchrony and synchronization underpinning sleep–wake cycles //The European Physical Journal Plus. – 2021. – Т. 136. – №. 5. – С. 1-19. 3. Merkulova K. O., Postnov D. E. The dynamical premise for desynchrony between circadian rhythm and the sleep-wake cycle //Saratov Fall Meeting 2020: Computations and Data Analysis: from Molecular Processes to Brain Functions. – International Society for Optics and Photonics, 2021. – Т. 11847. – С. 1184708.
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