Fear Of Sound Psychological Stress In Machine Learning And Memory In Mice On Different Stages Of System

Many documents have shown that psychological stress could damage the animal's learning and memory ability.Withal,as the gradual increasing of social competition,work stress and family variation and so on,the diseases related to psychological factors have been growing rapidly. Therefore,the research of the relation between the psychological stress and learning,memory as well as the influences on the learning and memory has become very important in the life science field.At present,there are many models on psychological stress and learning and memory in domestic,for example,exhaustive swimming,restraint,heat stress and electrocution.All are physical stresses and psychological stresses.It is difficult to assess the effect on learning and memory from the pure psychological viewpoint.Even at abroad the research on the relation between psychological stress and learning and memory only reach the level of the chronic stress.In the present experiment,the model in terrified sound stress was established successfully.The model animals were divided into four groups,including pregnant group,infant group,juvenescent group and control.The behavior,deformity and body weight at a fixed time were observed.The Morris water maze was used to test the spatial learning and memory abilities of the model mice in each group and different gender.The influence of the stress stimulation on learning and memory after the pregnancy,infancy and the juvenescent period were also detected.To explore the possible mechanism of the effects of stress on learning and memory,the fluorescence immunohistochemistry was utilized to observe the expression of N-methyl-D-aspartic acid receptor1(NMDAR1) in the hippocampal areas.High frequency stimulation(HFS) is usually adopted to study the dynamics and properties of Long-term potentiation(LTP) onset and consolidation in hippocampal CA1 area,and LTP at the Schaffer collateral-CA1 synapses is a well-established form of synaptic plasticity. Therefore,the range of LTP in the Schaffer collateral-CA1 through high-frequency stimulation was also analysed.The results showed that,compared with the control,after receiving terrified sound stimulation both the behavior of subject female mice at different phase and the weight were evidently influenced. In detail,the behavior changes including the two ears erecting,body curling,head burying in the particle,fleing,burrowing,unable to be captured,an increasing struggle degree,the relieved of bowel frequently and the favor of stacked.As to the weight change,the stimulation restrained the increasing of the mice weights,especially for the infanct group,but for male mice,vice versa.In addition,there were no influence on the birthrate and survival rate after the stimulation. The Morris water maze test showed that the space search strategies,after stimulation and compared with the control,the pregnant group mouse and infant group mouse did not form the cognitive ability basically while on the contrary the juvenescent group did,though worse than the control.As to the learning ability,the results from the Morris water maze indicated that the terrified sound stimulation could promote the learning ability for the female mice,but restrained the male's. Memory ability--the result of the Morris water maze indicated that the stimulation could promote the memory ability for the offspring of the pregnant mice,and restraint the infants and the juvenescents.However,In detail,the stimulation also influenced the memory for different gender. The memory abilities were restrainted for the infant and juvenescent female mice but promoted for the female offsprings of the pregnants,and for male mice,vice versa.The fluorescence immunohistochemistry indicated that terrified stimulation intensified the expression of subunit of NMDAR1 in the female mouse's CA1 and CA3 area,and restrained the expression in dentate gyrus and the expression of subunit of NMDAR1 in CA1,CA3 and dentate gyrus of male mice.Electrophysilological experiment showed that terrified sound stimulation promoted the induction and formation of the LTP in the hippocampal CA1 area.In conclusion,the model of terrified sound stimulation has been successfully established. Terrified sound stimulation promotes the learning ability of pregnant,infant and juvenescent subject female mice,but restraints the male's learning ability.The influences differ for subject mice of different phase and gender.The terrified sound stimulation may alter the behavior,learning ability and memory abilities of mice with a molecular mechanism involving the expressions of the subunit of NMDAR1 in the CA1,CA3 and dentate gyrus.