Study Of A Self-control Design Morris Water Maze Behavior Experiment Method And Its Evaluation

Background and objectiveThe Morris water maze is widely used in brain research as a popular behavioral test for assessing animal spatial learning and memory.There are many data in the Morris water maze experiment.How to select representative experimental indicators as the basis for evaluating the learning and memory level of animals is a prerequisite for obtaining correct and reliable conclusions in the experiment.At present,the general MWM experimental methods are difficult to control the individual differences and unreasonable processing and analysis of the main experimental results(escape latency),which may lead to the decrease of the reliability of the experimental results and the accuracy of the conclusions.Based on the above analysis,this study proposed a self-designed MWM experimental method,and adopted a more reasonable method to calibrate and evaluate the escape latency of its key indicators,in order to improve the reliability of the MWM experimental results and the accuracy of the conclusions.For this reason,we carefully designed and carried out the research of this project,obtained large amounts of reliable experimental data,and used Excel-VBA programming to assist the management,processing,analysis and statistics of experimental data.The present study also investigated the correlation between the high and low MWM learning ability and Long-term potentiation(LTP).Materials and Methods1.Animals: 80 male wild-type C57BL/6J aged 2-4 months,divided into 10 groups with 8animals in each group;each animal had only one fixed earring number throughout the experiment.2.Housing conditions: Isolation(one mouse per cage)56 mice?Group(four mice per cage)24 mice.3.Self-controlled MWM experiment: two rounds of MWM experiment were carried out for each animal,with one week interval between the two rounds.Each round of experiments was the same as the general MWM experiment method(suitable for 1 day,place navigation test for 5 days and probe test for 1 day).The experimental data were collected and preliminary processed by the MWM experimental system WMT100 produced by Chengdu Taimeng Company.After that,the management,comprehensive processing,analysis and statistics of MWM experimental data are realized by using Excel-VBA programming assistance.4.Method of drug administration: one week before the start of the two rounds of MWM experiment,all animals were intraperitoneally injected once a day for seven days: normal group,saline(0.9%Na Cl,0.1125g/kg);in the experimental group,alcohol(20%,2g/kg).5.Field potential recording of isolated hippocampal slices: According to the total corrected escape latency(TCEL)of the second round of MWM experiment,five animals with the strongest and weakest learning and memory in the isolated and group breeding groups were selected.Prepare animal hippocampal slices,measured from the hippocampus Schaffer collateral to the field excitatory postsynaptic potential of CA1 area,and electrophysiological parameters such as input-output relationship,paired-pulse ratio,and long-term potentiation were recorded.6.Statistics and analysis of data: All data in this experiment were expressed as Mean ± SD.Paired t-test,group t-test,two-way ANOVA were used as needed.P <0.05 indicates a significant difference.Results1.Through the analysis of the escape latency data of the place navigation test,it is found that the conventional method of taking a simple average(uncorrected)to reflect the learning and memory ability of animals is unreasonable,and the total corrected escape latency(TCEL)and uncorrected the data of is closely related(correlation coefficient is 0.9515),and can more reasonably reflect the learning and memory ability of animals,so all subsequent results are statistically analyzed by TCEL.2.The first round of MWM experiment(MWM1)found that: 1)compared with group rearing,isolated rearing increased the TCEL of normal group by about 5.9s(P<0.01);2)Compared with the normal group,alcohol had little effect on TCEL of group animals(P>0.05),but could prolong the TCEL of isolated animals by 7.8s(P<0.01).A second round of MWM experiment(MWM2)found that: 1)there was no significant difference in TCEL between isolated and group reared normal animals(P>0.05);2)Compared with normal,alcohol had no significant effect on TCEL in solitary animals(P>0.05).It was suggested that the animals that had just changed from normal group rearing to isolated rearing(all animals were group rearing one week before MWM1)had decreased learning and memory ability,and were sensitive to alcohol.However,after a longer adaptation time(two weeks),there was no difference in learning and memory ability between the two groups.3.By combining the results of MWM2 and MWM1,we found that: 1)compared with MWM1,TCEL of MWM2 in normal group decreased but had no significant difference(P>0.05);2)Compared with MWM1,TCEL of MWM2 was decreased by 10.4s(P<0.01),the TCEL of MWM2 in alcohol group 2 decreased by 6.9s(P>0.05).These results indicate that repeated training and growth can improve the learning and memory ability of animals from group rearing to isolated rearing,while alcohol may weaken this ability.However,the inter-group analysis of self-control showed that the medium concentration of alcohol used in this study,the way of application,and the solitary rearing mode in which the animals had enough time to adapt had no significant effect on the change of the learning and memory ability of the animals(P>0.05).4.Electrophysiological LTP and other experimental results: there was no significant difference in the LTP results between the strongest and weakest animals in the isolation group;Compared with the five animals with the strongest learning and memory in the group group,the slope value of the field excitatory postsynaptic potential at 50-60 minutes recorded by the LTP was significantly higher(P<0.05),indicating that there is a certain correlation between MWM learning and memory ability and LTP experimental results.Conclusion1.The total corrected escape latency(TCEL)can more reasonably reflect the learning and memory ability of individual animals.Combined with the self-controlled experimental design,it can more conveniently and effectively analyze the differences between different treatment groups.2.In the early stage of solitary care(within two weeks),the learning and memory ability of animals decreases,and they are sensitive to alcohol,which can be stabilized after three weeks.This will point out the direction for the optimization of subsequent research schemes.3.Excel-VBA programming to assist the processing,analysis and statistics of experimental data is more convenient and practical,conducive to the orderly accumulation of experimental data and the establishment of database,and traceable to the source.4.The relationship between spatial learning and memory ability of animals and LTP indexes of corresponding brain slices is not clear.