ABSTRACT
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 ( < 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.
Subject(s)
Humans , Brain , Cognition , Electroencephalography , Memory, Short-Term , MusicABSTRACT
BACKGROUND:Cytokines and neurotrophic factors secreted from human umbilical cord blood-derived mesenchymal stem cells secrete have neuroprotective effects on cerebral ischemia-reperfusion injury, but there are few reports about intranasal administration of human umbilical cord blood-derived mesenchymal stem cellconditioned medium in the treatment of stroke. OBJECTIVE:To investigate the protective effects of intranasal administration of human umbilical cord-derived mesenchymal stem cells-conditioned medium on neurologic function of rats with cerebral ischemia-reperfusion injury. METHODS:Adult rats were subjected to 2 hours of right middle cerebral artery occlusion and the human umbilical cord-derived mesenchymal stem cells were isolated from the postpartum human cord. We made the conditioned medium of human umbilical cord-derived mesenchymal stem cells. Ischemic rats were randomized and assigned to three groups and were treated by intranasal routine starting 24 hours after middle cerebral artery occlusion with:(1) saline for control group;(2) Dulbecco’s modified Eagle’s medium/Ham’s nutrient mixture F-12 medium for medium control group;(3) conditioned medium treatment group (10mL/kg) daily for 14 days. Behavioral tests (foot fault test, and modified Neurological Severity Score) were performed before and at 1, 7, 14 days after middle cerebral artery occlusion. RESULTS AND CONCLUSION:There was no difference in the behavioral tests among the three groups at postoperatively 1 day (P>0.05). Compared to the control and medium control group rats, respectively, rats in the conditioned medium group significantly improved functional outcome after stroke in days 7 and 14 (P0.05). These results suggest that human umbilical cord-derived mesenchymal stem cells-conditioned medium via intranasal administration can significantly improve neurologic functional outcome after cerebral ischemia-reperfusion injury.
ABSTRACT
Objective To study the tooth germ development of mouse molar in fluorosis.Methods We established an acute fluorosis model and used HE-staining after preparing specimens of different stage of mouse first molar developing tooth germ.Results The developing molars of the control fetuses were at the bell stage of odontogenesis,whereas those of the experimental population were at cap stage.The ameloblasts became shorter and lost polarity.The arrangement of ameloblasts fell into disorder at the bell of differeiational stage and secretory stage.Conclusion The developing molars of the experimental fetuses were retarded.High-dose fluoride has a strong effect in the ameloblasts at the bell of differetiational stage and secretory stage.