This study is aimed to investigate objective indicators of mental fatigue evaluation to improve the accuracy of mental fatigue evaluation. Mental fatigue was induced by a sustained cognitive task. The brain functional networks in two states (normal state and mental fatigue state) were constructed based on electroencephalogram (EEG) data. This study used complex network theory to calculate and analyze nodal characteristics parameters (degree, betweenness centrality, clustering coefficient and average path length of node), and served them as the classification features of support vector machine (SVM). Parameters of the SVM model were optimized by gird search based on 6-fold cross validation. Then, the subjects were classified. The results show that characteristic parameters of node of brain function networks can be divided into normal state and mental fatigue state, which can be used in the objective evaluation of mental fatigue state.
Mental fatigue is a subjective fatigue state caused by long-term brain activity, which is the core of health problems among brainworkers. However, its influence on the process of brain information transmission integration is not clear. In this paper, phase amplitude coupling (PAC) between theta and gamma rhythm was used to study the electroencephalogram (EEG) data recorded before and after mental fatigue, so as to explain the effect of mental fatigue on brain information transmission mechanism. The experiment used a 4-hour professional English reading to induce brain fatigue. EEG signals of 14 male undergraduate volunteers before and after mental fatigue were recorded by Neuroscan EEG system. Phase amplitude coupling value was calculated and analyzed. t test was used to compare the results between two states. The results showed that theta phase of more than 90% of the electrodes in the whole brain area jointly modulated gamma amplitude of the right central area and the right parietal area, and the coupling effect among different brain regions significantly decreased (P < 0.05) when participants had felt mental fatigue. This paper shows that phase amplitude coupling can explain the influence of mental fatigue on information transmission mechanism. It could be an important indicator for mental fatigue detection. On the other hand, the results also provide a new measure to evaluate the effect of neuromodulation in relieving mental fatigue.
Mental fatigue is the subjective state of people after excessive consumption of information resources. Its impact on cognitive activities is mainly manifested as decreased alertness, poor memory and inattention, which is highly related to the performance after impaired working memory. In this paper, the partial directional coherence method was used to calculate the coherence coefficient of scalp electroencephalogram (EEG) of each electrode. The analysis of brain network and its attribute parameters was used to explore the changes of information resource allocation of working memory under mental fatigue. Mental fatigue was quickly induced by the experimental paradigm of adaptive N-back working memory. Twenty-five healthy college students were randomly recruited as subjects, including 14 males and 11 females, aged from 20 to 27 years old, all right-handed. The behavioral data and resting scalp EEG data were collected simultaneously. The results showed that the main information transmission pathway of the brain changed under mental fatigue, mainly in the frontal lobe and parietal lobe. The significant changes in brain network parameters indicated that the information transmission path of the brain decreased and the efficiency of information transmission decreased significantly. In the causal flow of each electrode and the information flow of each brain region, the inflow of information resources in the frontal lobe decreased under mental fatigue. Although the parietal lobe region and occipital lobe region became the main functional connection areas in the fatigue state, the inflow of information resources in these two regions was still reduced as a whole. These results indicated that mental fatigue affected the information resources allocation of working memory, especially in the frontal and parietal regions which were closely related to working memory.
Analyzing the influence of mixed emotional factors on false memory through brain function network is helpful to further explore the nature of brain memory. In this study, Deese-Roediger-Mc-Dermott (DRM) paradigm electroencephalogram (EEG) experiment was designed with mixed emotional memory materials, and different kinds of music were used to induce positive, calm and negative emotions of three groups of subjects. For the obtained false memory EEG signals, standardized low resolution brain electromagnetic tomography algorithm (sLORETA) was applied in the source localization, and then the functional network of cerebral cortex was built and analyzed. The results show that the positive group has the most false memories [(83.3 ± 6.8)%], the prefrontal lobe and left temporal lobe are activated, and the degree of activation and the density of brain network are significantly larger than those of the calm group and the negative group. In the calm group, the posterior prefrontal lobe and temporal lobe are activated, and the collectivization degree and the information transmission rate of brain network are larger than those of the positive and negative groups. The negative group has the least false memories [(73.3 ± 2.2)%], and the prefrontal lobe and right temporal lobe are activated. The brain network is the sparsest in the negative group, the degree of centralization is significantly larger than that of the calm group, but the collectivization degree and the information transmission rate of brain network are smaller than the positive group. The results show that the brain is stimulated by positive emotions, so more brain resources are used to memorize and associate words, which increases false memory. The activity of the brain is inhibited by negative emotions, which hinders the brain’s memory and association of words and reduces false memory.
Background music has been increasingly affecting people’s lives. The research on the influence of background music on working memory has become a hot topic in brain science. In this paper, an improved electroencephalography (EEG) experiment based on n-back paradigm was designed. Fifteen university students without musical training were randomly selected to participate in the experiment, and their behavioral data and the EEG data were collected synchronously in order to explore the influence of different types of background music on spatial positioning cognition working memory. The exact low-resolution brain tomography algorithm (eLORETA) was applied to localize the EEG sources and the cross-correlation method was used to construct the cortical brain function networks based on the EEG source signals. Then the characteristics of the networks under different conditions were analyzed and compared to study the effects of background music on people’s working memory. The results showed that the difference of peak periods after stimulated by different types of background music were mainly distributed in the signals of occipital lobe and temporal lobe (P < 0.05). The analysis results showed that the brain connectivity under the condition with background music were stronger than those under the condition without music. The connectivities in the right occipital and temporal lobes under the condition of rock music were significantly higher than those under the condition of classical music. The node degrees, the betweenness centrality and the clustering coefficients under the condition without music were lower than those under the condition with background music. The node degrees and clustering coefficients under the condition of classical music were lower than those under the condition of rock music. It indicates that music stimulation increases the brain activity and has an impact on the working memory, and the effect of rock music is more remarkable than that of classical music. The behavioral data showed that the response accuracy in the state of no music, classical music and rock music were 86.09% ± 0.090%, 80.96% ± 0.960% and 79.36% ± 0.360%, respectively. We conclude that background music has a negative impact on the working memory, for it takes up the cognitive resources and reduces the cognitive ability of spatial location.
ObjectiveTo explore the effects of corticosteroid on peripheral blood T lymphocyte subsets in patients with coronavirus disease 2019 (COVID-19).MethodsThis was a retrospective study and 376 patients were included in the study. The patients were classified into three type: moderate type (118 patients), severe type (215 patients), critical type (43 patients). Six critical patients died. T lymphocyte subsets were analyzed and compared among these patients. In severe patients, T lymphocyte subsets were compared between no corticosteroid therapy patients (178 patients) and patients who were treated with corticosteroid for 3 to 5 days (37 patients).Results(1) In contrast with those in moderate patients, in severe patients total lymphocytes [(1359.2±597.9)×106 vs. (1703.7±702.4)×106/L, LSD-t=4.786, P<0.001], total T lymphocytes [(949.2±454.0)×106 vs. (1235.5±555.7)×106/L, LSD-t=5.175, P<0.001] and CD8+ T cells [(336.8±189.8)×106 vs. (461.7±242.8)×106/L, LSD-t=5.332, P<0.001] decreased significantly, and CD4+/CD8+ ratio (1.81±0.92 vs. 1.64±0.74, LSD-t=1.574, P=0.116) was increased. In contrast with those in severe patients, in critical patients CD4+/CD8+ ratio (2.23±1.24 vs. 1.81±0.92, LSD-t=2.627, P=0.009) increased and CD8+ T cells [(232.5±159.8)×106/L vs. (336.8±189.8)×106/L, LSD-t=2.867, P=0.004] decreased significantly, total lymphocytes [(1161.1±583.7)×106/L vs. (1359.2±597.9)×106/L, LSD-t=1.772, P=0.077], total T lymphocytes [(790.5±419.3)×106/L vs. (949.2±454.0)×106/L, LSD-t=1.846, P=0.066] also decreased but without significant difference. There was no significant difference between dead and survived critical patients. (2) In severe type, in contrast with no corticosteroid therapy patients, 37 patients were therapy with corticosteroid for 3 to 5 days, and their total T lymphocytes [(770.6±480.3)×106 vs. (986.3±440.7)×106/L, t=2.666, P=0.008] and CD4+/CD8+ ratio (1.30±0.73 vs. 1.91±0.92, t=3.771, P<0.001) were decreased significantly.ConclusionsIn COVID-19 patients, lymphocytes, T lymphocytes and CD8+ T cells are decreased, but CD4+/CD8+ ratio is increased, and these changes are positively related to the severity of the disease. After corticosteroid therapy, the increase of CD4+/CD8+ ratio is relieved, but T lymphocytes are decreased further.
Objective To explore the treatment methods for group Amanita exitialis poisoning, and summarize the treatment strategies for group Amanita exitialis poisoning. Methods A group of Amanita exitialis poisoning patients admitted to the Department of Emergency Medicine of the Affiliated Hospital of Yunnan University on July 31, 2023 were retrospectively included. We graded the patients’ condition and analyzed their clinical data, treatment methods, and blood purification selection modes. Results A total of 6 patients with Amanita exitialis poisoning were included, with an average age of 52 years. There were 2 patients with grade Ⅰ, 2 patients with grade Ⅱ, 1 patient with grade Ⅲ and 1 patient with grade Ⅳ. Grade Ⅰ patients choosed single one mode hemoperfusion (HP), grade Ⅱ patients choosed single multiple mode HP, grade Ⅲ patient choosed multiple mode HP combined with plasma exchange, and grade Ⅳ patient choosed multiple mode HP combined with plasma exchange, double plasma molecular adsorption system and continuous renal replacement therapy. After individualized comprehensive treatment, 5 patients were cured and discharged, and 1 patient died. Conclusions In the treatment of group Amanita exitialis poisoning, in addition to basic drug treatment, it is necessary to first consider factors such as the side effects of blood purification and the economic conditions of the patient. Then, according to the different disease grades of the patient, single or combined blood purification, single or multiple treatment modes can be choosed. Early selection of appropriate individualized blood purification modes can effectively buy time for poisoning patients.