Objective To explore the effects of mental fatigue on attention maintenance function by electroencephalogram(EEG)signal characteristics and cortical source analysis.Methods A total of 25 healthy males were recruited as subjects and contingent negative variation(CNV)auditory paradigm was used to assess the differences in EEG characteristics before and after mental fatigue,with the average amplitude of CNV at different processing stages as the analysis indices.Then,the 3-dimensional distribution of cortical current density changes of CNV after mental fatigue were calculated by standardized low-resolution electromagnetic tomography analysis(sLORETA).Results The reaction time of the CNV signal remained unchanged following mental fatigue(P＞0.05),while the lapse rate exhibited a significant increase(P＜0.05).Besides,mental fatigue was related to a notable decrease in the amplitude of CNV early components(500-1 000 ms after warning stimulus)at the central and central parietal electrodes,and a significant reduction in the amplitude of CNV late components(2 550-3 050 ms after warning stimulus)at the prefrontal,frontal,central,and central parietal electrodes(all P＜0.05).The results of sLORETA source analysis showed that the brain activity in the left posterior insular cortex decreased after mental fatigue during the late component of CNV(P＜0.05).Conclusion The decreased activation of the posterior insula,which plays a crucial role in sensorimotor information integration,could potentially serve as a neural mechanism for the reduction of CNV amplitude and the impairment of attention maintenance function following mental fatigue.

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ObjectiveTo explore the status of social anxiety and study the relationship between social anxiety and self-consciousness,self-esteem among primary students.MethodsUsing stratified randomization sampling method,568 primary students in grade 4 ～ 6 were investigated with social anxiety scale for children( SASC ),self-consciousness scale for children(PHCSS) and self-esteem scale(SES).Results①The score of SASC in the group of primary students was obviously higher than that of Chinese norm (P＜0.01).②The SASC and negative evaluation scores in the female were higher than the male (P ＜ 0.05 ),the negative evaluation scores in the sixth grade (3.22 ± 2.82) was higher than the fifth grade (2.53 ± 2.76,P ＜ 0.01 ) and fourth grade ( 2.54 ± 2.68,P＜ 0.05 ).The primary students in migrant workers elementary school,the single parent family and the relatively low income family had higher social anxiety scores than others(P＜0.05 ).③The SASC and two major factors were significantly negative correlated with the self-consciousness and each subscale( r =-0.202 ～ -0.511,P ＜ 0.01 ),and positive correlated with the self-esteem( r =0.282,0.270,0.305,P ＜ 0.01 ).④)The anxiety and gregariousness had significant prediction function of 25.5％ on negative evaluation,and 28.2％ on SASC,anxiety,gregariousness,intelligence and school situation had significant prediction function of 20.4％ on social avoidance and distress.ConclusionsPrimary students in grade 4 ～ 6 existed social anxiety.There are significant differences for their level of anxiety in different gender,grade,elementary school,family structure,monthly income.And social anxiety is closely related to self-consciousness and self-esteem.