非自然创伤叙事的认知迷宫--以《黑犬》中的创伤记忆呈现为例

因为时空跨越和叙述者的身份区隔,非自然叙事文本往往呈现出一种认知迷宫,读者需要在阅读进程中不断整合叙事结构与信息符码才能真正理解文本内涵,这在以人物叙述为主导的创伤回忆录中表现得尤为突出。本文以麦克尤恩有关大屠杀创伤记忆的小说《黑犬》为例,分析多重聚焦模式下的文本非自然叙事表象,探讨其中的创伤记忆呈现方式,在文本框架整合的基础上推导非自然创伤叙事可能的阅读模式塑型。

Exercise training and antioxidant supplementation independently improve cognitive function in adult male and female GFAP-APOE mice

Purpose： The purpose of this study was to determine if antioxidant supplementation, moderate exercise, and the combination of both treatments could ameliorate cognitive performance in adult mice and whether the apolipoprotein E （APOE） genotype as well as sex could influence the functional outcomes of the treatments. Methods： For a period of 16 weeks, separate groups of male and female mice expressing either the human APOE3 or APOE4 isoforms were fed either a control diet （NIH-31） or the control diet supplemented with vitamins E and C （1.12 IU/g diet a-tocopheryl acetate and 1.65 mg/g ascorbic acid）. The mice were further separated into a sedentary group or a group that followed a daily exercise regimen. After 8 weeks on the treatments, the mice were administered a battery of functional tests including tests to measure cognitive and affective function. Results： There was no effect of genotype or treatment on the learning performance in the Morris water maze. In the discriminated avoidance task, APOE4 mice performed better in learning the discrimination component of the task. Overall, exercise improved performance of APOE4 and APOE3 mice on various aspects of the active avoidance task. Antioxidant supplementation improved performance only in the APOE4 mice. On the test for anxiety, APOE4 mice spent more time in the open arms and supplementation with antioxidant reversed that effect. Conclusion： Exercise was the most effective treatment at improving cognitive function in both genotypes and sex, while antioxidants seemed to be effective only in the APOE4. In young adult mice only non-spatial learning and memory were improved. The combination of the two treatments did not yield further improvement in cognition, and there was no antagonistic action of the antioxidant supplementation on the beneficial effects of exercise.

Effect of electroacupuncture on the learning and memory abilities in type 2 diabetic model rats with cognitive impairment

Objective:To observe the effects of electroacupuncture(EA)on the protein and gene expressions of Bax,Caspase-3 and Bcl-2 in cerebral cortex of type 2 diabetic rats with cognitive impairment(CI),and to explore the mechanism of EA in improving the learning and memory abilities.Methods:A total of 100 Sprague-Dawley(SD)rats were divided into a normal group(n=10)and a model group(n=90)by random number table method.Rats in the model group were intraperitoneally injected with a small dose of streptozotocin(STZ)to establish the type 2 diabetic models,after being fed with high-fat and high-sugar diet for 1 month.Twenty CI rats were selected from the 50 successful model rats by the Morris water maze(MWM)test and randomly divided into a model group and an EA group according to the blood glucose level and MWM data(n=10).Rats in the EA group received acupuncture at Zusanli(ST 36),Neiting(ST 44)and Yishu(Extra),of which Zusanli(ST 36)and Neiting(ST 44)were stimulated by EA apparatus,20 min/time,once a day for 6 d a week and 4 consecutive weeks.The rats in the model and the normal groups were fixed without treatment.After 4-week treatment,the random blood glucose level of the rats was measured;the learning and memory abilities of rats were measured by MWM;terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling(TUNEL)assay was used to detect apoptotic cells;Western blot(WB)and real-time quantitative polymerase chain reaction(RT-qPCR)were used to detect the protein and gene expressions of Bax,Caspase-3 and Bcl-2 in cerebral cortex.Results:After modeling,the random blood glucose level and the escape latency tested by MWM were significantly increased,and the number of crossing the platform tested by the MWM was decreased in the EA and model groups,and were significantly different from those in the normal group(P<0.05 or P<0.01),while the differences between the model group and the EA group were not statistically significant(all P>0.05).After 4-week treatment,the random glucose level and the escape latency tested by MWM were significantly increased(both P<0.05),and the number of crossing the original platform tested by the MWM was significantly reduced(P<0.01),the protein and gene expressions of Bax and Caspase-3 were significantly increased(all P<0.001),the protein and gene expressions of Bcl-2 were significantly reduced(both P<0.001),and the number of neuron apoptosis was significantly increased(P<0.001)in the model group than in the normal group;the random blood glucose level was significantly reduced(P<0.05),the escape latency tested by MWM was significantly shortened(P<0.05),and the number of crossing the original platform tested by MWM was significantly increased(P<0.05),the protein and gene expressions of Bax and Caspase-3 were significantly reduced(all P<0.001),the protein and gene expressions of Bcl-2 were significantly increased(both P<0.001),and the number of neuron apoptosis was significantly reduced(P<0.001)in the EA group than in the model group.Conclusion:EA can improve the learning and memory damages induced by type 2 diabetic model rats with CI;the action mechanism may be achieved via anti-apoptosis.

Ingestion of Lactobacillus strain reduces anxiety and improves cognitive function in the hyperammonemia rat

Evidence suggests that the hyperammonemia （HA）-induced neuroinflammation and alterations in the serotonin （5-HT） system may contribute to cognitive decline and anxiety disorder during hepatic encephalopathy （HE）. Probiotics that maintain immune system homeostasis and regulate the 5-HT system may be potential treatment for HA-mediated neurological disorders in HE. In this study, we tested the efficacy of probiotic Lactobacillus helveticus strain NS8 in preventing cognitive decline and anxie- ty-like behavior in HA rats. Chronic HA was induced by intraperitoneal injection of ammonium acetate for four weeks in male Sprague-Dawley rats. HA rats were then given Lactobacillus helveticus strain NS8 （109 CFU mL 1） in drinking water as a dai- ly supplementation. The Morris water maze task assessed cognitive function, and the elevated plus maze test evaluated anxie- ty-like behavior. Neuroinflammation was assessed by measuring the inflammatory markers： inducible nitric oxide synthase, prostaglandin E2, and interleukin-1 13 in the brain. 5-HT system activity was evaluated by measuring 5-HT and its metabolite, 5-HIAA, and the 5-HT precursor, tryptophan. Probiotic treatment of HA rats significantly reduced the level of inflammatory markers, decreased 5-HT metabolism, restored cognitive function and improved anxiety-like behavior. These results indicate that probiotic L. helveticus strain NS8 is beneficial for the treatment of cognitive decline and anxiety-like behavior in HA rats.

Effects of Compound Danshen tablets(复方丹参片) on spatial cognition and expression of brain β-amyloid precursor protein in a rat model of alzheimer's disease

OBJECTIVE:To observe the effects of Compound Danshen Tablets(CDST) on spatial cognition and expression of brain b-amyloid precursor protein(β-APP) in a rat model of Alzheimer's disease.METHODS:The rat model of Alzheimer's disease(AD) was established using D-galactose to cause subacute aging combined with Meynert nucleus damage.Rat behavior was monitored using the Morris water maze,and the expression of β-APP in rat brain tissue was detected via immunohistochemistry.RESULTS:CDST significantly improved spatial cognition and decreased β-APP expression in the cortex and hippocampus(P<0.05,P<0.01).CONCLUSIONS:CDST can significantly improve spatial cognition in a rat model of AD.This observation is possibly related to a reduction in β-APP ex-pression in the rat brain.