Research On The Total Sleep Deprivation Of Rats Based On Default Mode Network

Sleep is important in our daily life and the research of sleep deprivation can provide insights into the mechanistic understanding of sleep.Recent experimental studies based on functional magnetic resonance imaging(fMRI)have shown that the changes of default mode network(DMN)can reflect the lack of cognitive behavior after a long-term sleep deprivation,but the impact of total sleep deprivation(TSD)on electrophysiology DMN remains unclear.In this thesis,we recorded the synchronized local field potentials of rats which were subjected to four hours TSD.Then,we used EEG power spectra and complexity analysis to find the change of single DMN brain area.In addition,we conducted functional network research and used a dynamic analysis method to investigate changes of brain functional connectivity and topography in different frequency bands after TSD.The main results of this thesis are summarized as follows:(1)By performing the sleep stage analysis,we found that both REM and SWS phase could rebound after sleep deprivation,mainly for the significant increase of sleep time and frequency.The frequency of the two phases increased significantly,while the average duration didn’t change significantly.(2)There was a significant change in the power spectrum of SWS phase after sleep deprivation.The power of SWS were increased significantly in the Delta band with the center-frequency shifting to the low frequencies,and there were no marked power change in REM phase after total sleep deprivation.The results of the complexity analysis showed that the prelimbic cortex(Pr L)in the REM phase were significantly reduced in complexity after TSD,while the SWS phase exhibited a significant decreased complexity in the whole brain region after TSD.(3)By comparing the functional networks before and after TSD,we found that the effects of TSD on REM phase were concentrated in the Theta and Alpha frequency bands,and the connections between PrL and posterior brain regions decreased significantly at the first hour after TSD.Our results also showed that the effects of TSD on SWS phase were concentrated in the Delta and Theta frequency bands,and the connection between the PrL cortex and the posterior brain region increased at first and then showed a recovery tendency.By further conducting the dynamic network analysis,we observed that the inherent spatial patterns in DMN at 1-8 Hz frequency regions,including the common patterns existing in both SWS and REM phases and the independent patterns which are unique in a single phase.The main effects of REM phase were related to the patterns of Pr L,parietal lobe and hippocampus,and SWS phase deprivation was mainly associated with the frontal and parietal lobe.In summary,our results suggest that TSD mainly influences the connectivity of DMN at the low frequency bands.In particular,we found that both REM and SWS phases exhibit a certain inherent spatial patterns within DMN,and TSD may change these inherent spatial patterns by mainly altering the connections related to PrL area.These findings provide a new theoretical basis for understanding the effects of TSD on REM and SWS phases in DMN,identify the inherent spatial patterns existed in different sleep phases,as well as inspire novel insights into the neural mechanisms underlying sleep disorder.