Objective Sleep is an important physiological process for maintaining normal cognitive functions,but with the accelerated pace and increased work pressure in modern society,sleep deprivation has become a common phenomenon.It has been shown that sleep deprivation interferes with higher cognitive functions such as working memory,but the specific mechanism of its effect is still not completely clear.The present study aimed to systematically investigate the effects of 36 hours of sleep deprivation on the stages of the working memory processing chain and its neural mechanisms through behavioral and event-related potential(ERP)techniques.Methods Using a randomized controlled experimental design,48 healthy adult subjects were recruited and randomly assigned to sleep deprivation and control groups.All subjects completed a 2-back phonological working memory task,and behavioral data(response time and correctness)and ERP data(P2,N2,and P3 component wave amplitudes)were collected at 0 and 36 hours,respectively.The effects of sleep deprivation on working memory behavioral performance and neurophysiological indices were assessed by ANOVA.Results Behavioral results showed that the sleep deprivation group had a significantly longer response time after 36 hours,but no significant decrease in correctness,indicating a decrease in response efficiency but stable accuracy.ERP results showed that P2 amplitude did not change significantly before and after sleep deprivation,indicating that the early perception and categorization stages were limitedly affected by sleep deprivation;whereas,N2 and P3 amplitudes decreased significantly after sleep deprivation,reflecting that later cognitive processing such as conflict monitoring and resource allocation and other late cognitive processing were significantly disturbed.Conclusion Through ERP technology,this study uncovers the phased impact of 36-hour sleep deprivation on the working memory processing chain.The study found that early perceptual and categorization stages may be less susceptible to the effects of sleep deprivation,likely due to their relatively automatic processing and lower demand for cognitive resources.In contrast,during later stages of cognitive processing,particularly in higher-order functions such as conflict monitoring and resource allocation,sleep deprivation significantly impaired task performance efficiency by disrupting prefrontal cortex function.This finding deepens the understanding of the mechanisms underlying the effects of sleep deprivation and provides a scientific basis for cognitive intervention and management strategies in high-stress occupational groups.Future studies can further explore the long-term effects of sleep deprivation and its neural mechanisms by combining multimodal techniques.

Purpose To observe the impact of sleep deprivation (SD) for 24 hours on human brain regional homogeneity (ReHo) by using functional magnetic resonance imaging (fMRI),and briefly discuss the intervening effect of transcranial direct current stimulation (tDCS) on ReHo after SD.Material and Methods Sixteen healthy individuals were enrolled,and self-controlled study were adopted.Resting-state fMRI scans were performed in wakefulness,after SD,and after tDCS (true or placebo stimuli).The ReHo analysis approach was employed to calculate the ReHo values of whole brain in different states.The differences between before and after SD,and between true and false tDCS after SD,were analyzed.Results Compared with wakefulness,SD mainly enhanced ReHo in brain regions of left precentral gyrus,right precentral gyrus,bilateral temporal lobe and thalamus,but decreased ReHo in brain regions of right precuneus,left superior occipital gyrus,limbic lobe and bilateral angular gyrus,superior frontal gyrus,middle frontal gyrus.Compared with placebo stimuli,the true tDCS enhanced ReHo in brain regions of bilateral precuneus,angular gyrus and right forehead,superior middle gyrus,but decreased ReHo in brain regions of the medial side of left frontal lobe,right precentral gyrus,parahippocampal gyrus,substantia nigra and bilateral temporal lobe,pons and so on.Conclusion SD can cause ReHo change in a large number of brain regions.The tDCS on the prefrontal cortex improves the brain regions with ReHo reduction caused by SD.The improved brain regions mainly include bilateral precuneus/posterior cingulate cortex.Therefore,tDCS on the prefrontal cortex can improve brain dysfunction caused by SD.

Objective To explore the effect of sustained performance on EEG approximate entropy (ApEn).Methods Fifty participants were divided into two groups according to whether they had undergone sustained performance .One day af-ter the sustained-performance group finished executing their task , the resting EEG of nine electrodes ( F3, Fz, F4, C3, Cz, C4, P3, Pz and P4) was acquired in two grups separately , and the ApEn of each electrode was calculated as well . Results The ApEn of F3 and Fz showed an evident decrease as well as randomness of spontaneous brain electrode activity in frontal lobes , especially in the left one .Conclusion The drop of ApEn and the asymmetry of frontal lobes might reflect participants′state of fatigue during sustained performance .

Objective:To explore the impact of total sleep deprivation (TSD) on executive control function.Methods:Thirteen healthy young men completed visual Go/No-go task before and after the 36 hour sleep deprivation.Functional magnetic resonance imaging (fMRI) was carried out in these subjects 3 weeks apart.Results: The hit rate of Co/No-go task decreased (P