Research On The Brain Network Mechanism Of Sleep State Transition Under Different Sleep Deprivations In Rats

ABSTRACTSleep is an important and indispensable physiological state for both human and animals.Sleep Deprivation(SD),which deprives the normal rhythm of sleep,is often used to study the brain mechanism of sleep disorders.The change in the default mode network(DMN)connection during sleep can reflect the change in the level of consciousness.People study the mechanism of sleep by studying the change in DMN connection during sleep.The transition between sleep states can enable the brain to achieve different functions,and the mechanism about this transition has been widely explored.However,whether SD affects the organism's sleep state transition process is still unclear.To address this question,the current thesis used data on the normal sleep state,the recovery period after 4 hours of rapid eye-movement sleep(REMS)deprivation and the recovery period after total sleep deprivation(TSD)of rats.Through the power density of the DMN brain area,the complexity,the functional connectivity of the brain area,cross-band coupling and sleep energy distribution analysis,we explored the mechanism of sleep state transition under different sleep deprivations in rats.The main findings are as follows:1.TSD could increase the need for rats to re-enter sleep,so the power spectrum increased during the entire sleep transition period,and the complexity of the DMN brain area enhanced during the slow wave sleep(SWS)state,but decreased during the REMS state;However,the REMSD reduced power spectrum and increased the complexity of the DMN brain region during SWS state,while the power spectrum increased during REMS state.Besides,there was no significant difference in the complexity of the brain region during REMS state.2.REMSD had a strong effect on the connection of various DMN brain regions in rats within a short period of time before and after re-entering REMS.In the delta and alpha bands,the interaction between the anterior brain area and the posterior brain area were greatly enhanced,and the activity of the hippocampus and temporal lobe were greatly increased.Theta band showed strong temporal lobe and posterior brain area activity;TSD had a greater impact on the DMN brain area connection during the entire sleep transition period in rats.The alpha frequency band was mainly manifested in the reduction of the contact activity of each brain region itself and the brain region.In the theta frequency band,it showed that the brain regions of each module enhance their own and interconnected activities.3.REMSD made the hippocampal regulation on the contralateral side continue to be weaken during the REMS period,and its regulation on itself enhanced firstly and then weakened.The enhancement frequency band was near 80 Hz,and the attenuation frequency band was 60-100 Hz.TSD made the hippocampus significantly enhance the contralateral and self-regulation when rats enter the REMS period,and the frequency band was concentrated at 60-100 Hz.4.REMSD and TSD both caused theta rhythm oscillation to increase in the SWS phase of sleep transition in rats,which helped the rats switch from SWS to REMS.However,after entering the REMS period,REMSD weakens theta rhythm oscillations in rats,indicating that the brain activity in REMS could be completed without strong theta rhythm oscillation.Both types of sleep deprivation caused the rat's mid-low frequency oscillation in DMN brain regions to weaken during sleep transition.It showed that midlow frequency oscillation played a major role in normal sleep.Our above results showed that different sleep deprivations had different effects on the sleep state transition of rats.After REMSD,various mechanisms of DMN brain network would be significantly changed when SWS enters REMS during sleep transition in the recovery period;and TSD on rats would affect the DMN connection during the whole sleep transition process.These results provide new ideas and directions for the study of sleep transition under abnormal sleep.