Study On Anxiety And Depression-like Behaviors Of Male Brandt's Vole(lasiopodomys Brandtii)basing On Personalities

Personality is the consistent behavioral differences of animals,which is maintained under different environment contexts.Personality is influenced both by internal and external factors.Personality widely exists in animals and is closely related to ecology,heredity and evolution of population and individuals.Anxiety is a common emotion,especially in some stressful situations.Depression is a pathological condition that affects cognitive processes such as memory.When disturbed by depression for a long time,the external behavior of animals will change,that is,they will show depression-like behavior.Some depression-like behaviors in animals are similar to the symptoms of human depression.Therefore,the research on depression-like behavior in animals has a profound significance,which will help human to understand the pathogenesis of depression and develop new drugs.This study used the open-field and mirror-image apparatus to evaluate the personality of Brandt's vole,and selected the shy individuals and the bold individuals to study.The open field test,the risk test and the interspecific interaction test were used to evaluate the anxiety behavior.After above experiments,Brandt's vole was treated by the CUMS(chronic unpredictable mild stress).The sucrose preference test,forced swimming test and tail suspension test were used to evaluate the depressive-like behavior.The memory and cognitive ability were evaluated by the spontaneous alternation test and the new arm test in the Y-maze device.Through the above experiments,the relationships among personality characteristics,anxiety behavior and depression-like behavior was discussed,and the effect of CUMS on memory and cognitive ability was also discussed.The main research results are as follows:1.Anxiety behavior of Brandt's vole basing on personalities.Based on the personality test,the anxiety behavior under different situations were tested.The results showed that the anxiety of shy individuals was higher than bold individuals,and the response of shy individuals to predation risk were slower than the bold individuals.The results were as follows: 1)When entering the new open environment,the activity of the bold individuals were higher,while the activity of the shy individuals were lower;2)In the environment with potential predation risk,the bold individuals could avoid the risk faster,while the shy individuals had weaker response to the risk;3)Under stronger competitive pressure,the bold individuals actively socialized,while the shy individuals were more timid and passively socialized;4)Under weaker competitive pressure,both shy and bold individuals showed actively social behavior;5)The anxiety of Brandt's vole with different personalities was consistent in different situations.2.Depression-like behavior of Brandt's vole basing on personalities.Through monitoring the depression-like behavior in the process of chronic mild stimulation,we analyzed the differences of depression-like behavior between two types of personalities of Brandt's vole.The results showed that with the increase of chronic mild stimulation time,the depression degree of shy individuals gradually increased.For the shy individuals,the ratio of consumption of sucrose solution was decreased while the immobile time in the forced swimming test and the tail suspension test was also increased.For the bold individuals,no significant changes were observed in the ratio of consumption of sucrose solution and the immobile time.The bold individuals had "elastic resilience" under chronic stress,and their ability to self-regulation was stronger than the shy individuals.3.The effect of CUMS on memory and cognitive ability of different personality Brandt's vole.In this study,personalities and cognition ability were associated.The effects of personality and chronic stress on memory and cognitive ability in animals were discussed.The results showed that chronic mild stress reduced the spatial working memory and reference working memory ability of Brandt's vole.In other words,their memory and cognitive ability was impaired by the chronic mild stress.In summary,the anxiety behavior and the depression-like behavior were different in Brandt's vole with different personalities.Chronic mild stress can damage memory and cognitive ability of Brandt's vole.Personalities of animals are closely related to anxiety behavior,depression-like behavior,memory and cognitive ability.