In order to study the relationship between landmarks and spatial memory in short-nosed fruit bat, Cynopterus sphinx （Megachiroptera, Pteropodidae）, we simulated a foraging environment in the laboratory. Different la...In order to study the relationship between landmarks and spatial memory in short-nosed fruit bat, Cynopterus sphinx （Megachiroptera, Pteropodidae）, we simulated a foraging environment in the laboratory. Different landmarks were placed to gauge the spatial memory of C. sphinx. We changed the number of landmarks every day with 0 landmarks again on the fifth day （from 0, 2, 4, 8 to 0）. Individuals from the control group were exposed to the identical artificial foraging environment, but without landmarks. The results indicated that there was significant correlation between the time of the first foraging and the experimental days in both groups （Pearson Correlation： experimental group： r=-0.593, P〈0.01; control group： r=-0.581, P〈0.01）. There was no significant correlation between the success rates of foraging and the experimental days in experimental groups （Pearson Correlation： r=0.177, P〉0.05）, but there was significant correlation between the success rates of foraging and the experimental days in the control groups （Pearson Correlation： r=0.445, P〈0.05）. There was no significant difference for the first foraging time between experimental and control groups （GLM： F0.05,1=4.703, P〉0.05）; also, there was no significant difference in success rates of foraging between these two groups （GLM： F0.05,1=0.849,P〉0.05）. The results of our experiment suggest that spatial memory in C. sphinx was formed gradually and that the placed landmarks appeared to have no discernable effects on the memory of the foraging space.展开更多
A deficit in spatial memory has been taken as an early predictor of Alzheimer’s disease(AD)or mild cognitive impairment(MCI).The uncinate fasciculus(UF)is a long-range white-matter tract that connects the anterior te...A deficit in spatial memory has been taken as an early predictor of Alzheimer’s disease(AD)or mild cognitive impairment(MCI).The uncinate fasciculus(UF)is a long-range white-matter tract that connects the anterior temporal lobe with the orbitofrontal cortex(OFC)in primates.Previous studies have shown that the UF impairment associated with spatial memory deficits may be an important pathological change in aging and AD,but its exact role in spatial memory is not well understood.The pathway arising from the postrhinal cortex(POR)and projecting to the ventrolateral orbitofrontal cortex(vlOFC)performs most of the functions of the UF in rodents.Although the literature suggests an association between spatial memory and the regions connected by the POR–vlOFC pathway,the function of the pathway in spatialmemory is relatively unknown.To further illuminate the function of the UF in spatial memory,we dissected the POR–vlOFC pathway in mice.We determined that the POR–vlOFC pathway is a glutamatergic structure,and that glutamatergic neurons in the POR regulate spatial memory retrieval.We also demonstrated that the POR–vlOFC pathway specifically transmits spatial information to participate in memory retrieval.These findings provide a deeper understanding of UF function and dysfunction related to disorders of memory,as in MCI and AD.展开更多
Memantine is a N-methyl-D-aspartate (NMDA) receptor antagonist approved for the treatment of moderate to severe Alzheimer's disease (AD). Environmental enrichment (EE) has shown significant beneficial effects on f...Memantine is a N-methyl-D-aspartate (NMDA) receptor antagonist approved for the treatment of moderate to severe Alzheimer's disease (AD). Environmental enrichment (EE) has shown significant beneficial effects on func- tional improvement in AD. In this study, we sought to determine whether combining these two distinct therapies would yield greater benefit than either drug used alone. We investigated the effect of memantine combined with EE on spatial learning and memory and AD-like pathology in a widely used AD model, the senescence-accelerated prone mice (SAMP8). The SAMP8 mice were randomly assigned to enriched housing (EH) or standard housing (SH), where either memantine (20 mg/kg) or saline was given by gastric lavage once daily continuously for eight weeks. Our results showed that, when provided separately, memantine and EE significantly improved spatial learning and memory by shortening escape latencies and increasing the frequency of entrance into the target quadrant. When combined, memantine and EE showed additive effect on learning and memory as evidenced by significant shorter escape latencies and higher frequency of target entrance than either drug alone. Consistent with the behavior results, pathological studies showed that both memantine and EE significantly reduced hippocampal CA1 neurofibrilliary tangles (NFTs) as well as amyloid beta precursor protein (APP) levels. Combining both therapies synergistically lessened NFTs and APP expression compared to either drug alone in SAMP8 mice, indicating that the combination of memantine with EE could offer a novel and efficient therapeutic strategy for the treatment of AD.展开更多
3, 4-methylenedioxymethamphetamine （MDMA; also known as ＇ecstasy＇） has been shown to impair learning and spatial memory in adult and neonatal rats. Many studies have focused on the acute effects of MDMA on memory....3, 4-methylenedioxymethamphetamine （MDMA; also known as ＇ecstasy＇） has been shown to impair learning and spatial memory in adult and neonatal rats. Many studies have focused on the acute effects of MDMA on memory. In the present study, we intraperitoneally administered MDMA （0, 5, 10, 20 mg/kg） to adult male rats to investigate the effects of different doses on rat spatial memory in the Morris water maze, body temperature, and mortality, twice a day, for 7 successive days. The results indicated that MDMA impaired spatial memory dose-dependently, with the highest dose （20 mg/kg） exerting the strongest effects. In addition, MDMA also caused hyperthermia and increased mortality in rats展开更多
Objective: To observe the effect of Tiaoxin Recipe (TXR) on the spatial memory, brain mitochondrial energy metabolism of oxidation injured Alzheimer's disease (AD) rats, and to explore the mechanism of TXR in trea...Objective: To observe the effect of Tiaoxin Recipe (TXR) on the spatial memory, brain mitochondrial energy metabolism of oxidation injured Alzheimer's disease (AD) rats, and to explore the mechanism of TXR in treating AD. Methods: Eighty-eight SD rats were randomly divided into five groups (normal group, operative group, "AD" model group,TXR group and Aricept group). An oxygen free radical generation system (dihydroxy fumaric acid-trichloroferric-adenosine diphosphate, DHF-FeCl3-ADP) was used to create oxidation injured rat models mimic to AD; spatial learning and memory impairment (Morris water maze method), the activity of Succinate-oxidase, NADH-oxidase, CytC-oxidase (Clark oxygen electrode method) and the expression of cytochrome oxidase (CO) II mRNA (in situ hybridization method) were observed. Results: Compared with the normal group, the spatial memory, activity of CytC-oxidase and COII mRNA expression of oxidation injured "AD" rats were obviously decreased; TXR, however, could improve these functions in "AD" rat models obviously. Conclusion: The mechanism of the action of TXR in treating AD was partly related to its effect on anti-oxidation which could improve brain mitochondrial energy metabolism.展开更多
In this paper,we introduce spatial memory into a predator–prey model with herd behavior.Taking memory-based diffusion coefficient and average memory period of predators as control parameters,we obtain the stable cond...In this paper,we introduce spatial memory into a predator–prey model with herd behavior.Taking memory-based diffusion coefficient and average memory period of predators as control parameters,we obtain the stable conditions of the positive equilibrium of system and prove the existence of Hopf bifurcation.In addition,a double Hopf bifurcation occurs at the intersection of the nonhomogeneous Hopf bifurcation curves,and a spatially nonhomogeneous quasi-periodic pattern can be observed near the double Hopf bifurcation point by numerical simulation.展开更多
Working memory is a core cognitive function that supports goal-directed behavior and complex thought.We developed a spatial working memory and attention test on paired symbols(SWAPS)which has been proved to be a usefu...Working memory is a core cognitive function that supports goal-directed behavior and complex thought.We developed a spatial working memory and attention test on paired symbols(SWAPS)which has been proved to be a useful and valid tool for spatial working memory and attention studies in the fields of cognitive psychology,education,and psychiatry.The repeated administration of working memory capacity tests is common in clinical and research settings.Studies suggest that repeated cognitive tests may improve the performance scores also known as retest effects.The systematic investigation of retest effects in SWAPS is critical for interpreting scientific results,but it is still not fully developed.To address this,we recruited 77 college students aged 18–21 years and used SWAPS comprising 72 trials with different memory loads,learning time,and delay span.We repeated the test once a week for five weeks to investigate the retest effects of SWAPS.There were significant retest effects in the first two tests:the accuracy of the SWAPS tests significantly increased,and then stabilized.These findings provide useful information for researchers to appropriately use or interpret the repeated working memory tests.Further experiments are still needed to clarify the factors that mediate the retest effects,and find out the cognitive mechanism that influences the retest effects.展开更多
This is an Open Access article published by World Scientific Publishing Company.It is distributed under the terms of the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0(CC BY-NC-ND)License,which permits u...This is an Open Access article published by World Scientific Publishing Company.It is distributed under the terms of the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0(CC BY-NC-ND)License,which permits use,distribution and reproduction,provided that the original work is properly cited,the use is non-commercial and no modifications or adaptations are made.The cognitive abilities of animals,such as memory,have a significant impact on their movement in space.In this paper,we consider a radio-dependent model with memorybased diffusion under the conditions of Neumann boundary.The stability of a positive equilibrium and the existence of the Turing-Hopf bifurcation induced by memory diffusion and memory delay are carried out in details.Notably,our findings indicate that with a relatively short average memory period,the large memory diffusion can stabilize an otherwise unstable equilibrium.In addition,the third-order truncated normal form for the Turing-Hopf bifurcation restricted to the central manifold is derived,which can reveal the generation of some steady-state and time-periodic solutions with spatial heterogeneity.The coefficients within the normal form are systematically determined through matrix operations,and these results can also be applied to other models with memory diffusion.Ultimately,leveraging the theoretical findings,we elucidated the intricate spatial-temporal dynamics and their associated parameter scopes caused by Turing-Hopf bifurcation through numerical simulations.展开更多
Background:Mitochondrial dysfunction plays a critical role in the pathogenesis of Alzheimer’s disease(AD).Resveratrol is a promising compound for the treatment of various neurodegenerative diseases,including AD.Aims:...Background:Mitochondrial dysfunction plays a critical role in the pathogenesis of Alzheimer’s disease(AD).Resveratrol is a promising compound for the treatment of various neurodegenerative diseases,including AD.Aims:To investigate mitochondrial damage and the effects of resveratrol on inflammation,cognitive function,and mitochondrial quality control in APP/PS1 mice.Methods:Comparative analysis of mitochondrial DNA(mtDNA)damage was conducted between 10-month-old APP/PS1 mice and age-matched C57BL/6 mice.Assessments included measurement of amyloid-βlevels,inflammatory markers,swimming distance in the Morris water maze,and gut microbiome composition.Resveratrol’s effects on cytokine expression,mtDNA levels in plasma,and activation of Nuclear factor erythroid 2-related factor 2/Antioxidant response element(Nrf2/ARE)and phosphoinositide 3-kinase/protein kinase B(also known as Akt)/mechanistic target of rapamycin complex 1(PI3K/Akt/mTORC1)signaling pathways were also evaluated.Results:APP/PS1 mice exhibited significantly increased mtDNA damage in the prefrontal cortex,midbrain,and cerebellum,alongside higher amyloid-βlevels and inflammatory markers.Resveratrol treatment led to reduced expression of pro-inflammatory cytokines,a decrease in Proteobacteria levels,and lower cell-free mtDNA in plasma.Partial improvement in long-term spatial memory was observed in APP/PS1 mice following resveratrol treatment,likely due to its anti-inflammatory properties.Activation of the Nrf2/ARE signaling pathway and markers of PI3K/Akt/mTORC1 axis activation were noted,with the latter regulating long-term potentiation.Conclusion:Resveratrol demonstrates potential in mitigating inflammation and improving mitochondrial quality control in APP/PS1 mice,but it does not reduce amyloid-βlevels,highlighting the complexity of AD pathology and the need for further research.展开更多
The relation between evolution of spatial working memory function and of morphology of the dorsolateral prefrontal cortex among the rhesus monkey (Macaca mulatta), the slow loris (Nycticebus coucang) and the tree shre...The relation between evolution of spatial working memory function and of morphology of the dorsolateral prefrontal cortex among the rhesus monkey (Macaca mulatta), the slow loris (Nycticebus coucang) and the tree shrew (Tupaia belangen chinensis) were reported in present paper. The results read as follows: In the DR performance with training, the rhesus monkeys and slow lorises could reach a criterion of 90% correct response at 1.1 ± 3.2 seconds, and 3.8±0.4 seconds delay interval, respectively, by 1000 training trails. The tree shrews failed to reach the criterion of 90% correct response even at 0 seconds delay interval by 1000 training trails. If a delay interval was tested in one session (30 trails) only, doing the DR performamce without training, the rhesus monkeys reached a correct of 80% or higher in each session at 0, 1, 2, 3, 4, and 5 seconds delay, respectively. The percent correct in each session of the slow lorises showed no differences from the rhesus monkeys at 0, 1, 2, 3, and 4 seconds delay. However, when the delay interval was increased to 5 seconds, the percent correct of the DR performance declined to 70% or lower in the slow lorises. In the tree shrews the percent correct in each session reached to 70% or lower at 0, 1, 2, 3, 4, and 5 seconds delay interval, respectively. The morphological studies revealed that the size of the prefrontal cortex increased, and the structure got complex in the course of the evolution in primates. It is suggested that the relation of evolution between the spatial working memory function and anatomy in the prefrontal cortex might be significant among the three species, both the development of morphology and that of the spatial working memory function in the dorsolateral prefrontal cortex are later than other regions of cerebral cortex in phylogenetic evolution course.展开更多
Background Human amniotic epithelial cells （HAECs）, which have characteristics of both embryonic and pluripotent stem cells, are therefore a candidate in cell therapy without creating legal or ethical problems. In t...Background Human amniotic epithelial cells （HAECs）, which have characteristics of both embryonic and pluripotent stem cells, are therefore a candidate in cell therapy without creating legal or ethical problems. In the present study, we aimed to investigate the effects of intracerebroventricular transplantation of HAECs on doubly transgenic mice of Alzheimer＇s disease （AD） coexpressing presenilin-1 （PS1） and mutant Sweden amyloid precursor protein （APPswe） genes. Methods The offspring mice genotypes were detected using PCR identification of APPswe and PS1 gene. The doubly transgenic （TG） mice （n=20） and wild-type （WT） mice （n=20） were randomly divided into two groups respectively： the transplantation group treated with HAECs and the control group with phosphate buffered saline. Six radial arm water maze test was used to assess the spatial memory in the TG and WT mice. Amyloid plaques and neurofibrillary tangles were analyzed using congo red and acid-silver methenamine staining respectively. was used to track the survival of HAECs. Immunohistochemistry was used octamer-binding protein 4 （Oct-4） and Nanog in the HAECs. High performance measure acetylcholine in hippocampus. The density of cholinergic neurons in hippocampus was measured using acetylcholinesterase staining. Immunofluorescence cytochemistry to determine the expression of quid chromatography was used to basal forebrain and nerve fibers in Results Amyloid deposition occurred in hippocampus and frontal cortex in the double TG mice aged 8 months, but not in WT mice. The results also showed that transplanted HAECs can survive for at least 8 weeks and migrate to the third ventricle without immune rejection. The graft HAECs can also express the specific marker Oct-4 and Nanog of stem cell. Compared with the control group, transplantation of HAECs can not only significantly improve the spatial memory of the TG mice, but also increase acetylcholine concentration and the number of hippocampal cholinergic neurites. Conclusions These results demonstrate that intracerebroventricular transplantation of HAECs can improve the spatial memory of the double TG mice. The higher content of acetylcholine in hippocampus released by more survived cholinergic neurites is one of the causes of this improvement.展开更多
In Alzheimer抯 disease (AD), hyperphosphorylation of tau may be the underlying mechanism for the cytoskeletal abnormalities and neuronal death. It was reported that cy-clin-dependent kinase5 (cdk-5) could phosphorylat...In Alzheimer抯 disease (AD), hyperphosphorylation of tau may be the underlying mechanism for the cytoskeletal abnormalities and neuronal death. It was reported that cy-clin-dependent kinase5 (cdk-5) could phosphorylate tau at most AD-related epitopes in vitro. In this study, we investigated the effect of cdk-5 overexpression on tau phosphorylation and spatial memory in rat. We demonstrated that 24 h after transfection into rat hippocampus, cdk-5 was overexpressed and induced a reduced staining with antibody tau-1 and an enhanced staining with antibodies 12e8 and PHF-1, suggesting hyperphosphorylation of tau at Ser199/202, Ser262/356 and Ser396/404 sites. Additionally, the cdk-5 transfected rats showed long latency to find the hidden platform in Morris water maze compared to the control rat. 48 h after transfection, the level of cdk-5 was decreased significantly, and the latency of rats to find the hidden platform was prolonged. It implies that in vivo overexpression of cdk-5 leads to impairment of spatial memory in rat and tau hyperphosphorylation may be the underlying mechanism.展开更多
The raphe nucleus is critical for feeding, rewarding and memory. However, how the heterogenous raphe neurons are molecularly and structurally organized to engage their divergent functions remains unknown. Here, we gen...The raphe nucleus is critical for feeding, rewarding and memory. However, how the heterogenous raphe neurons are molecularly and structurally organized to engage their divergent functions remains unknown. Here, we genetically target a subset of neurons expressing VGLUT3. VGLUT3 neurons control the efficacy of spatial memory retrieval by synapsing directly with parvalbumin-expressing GABA interneurons(PGIs) in the dentate gyrus. In a mouse model of Alzheimer's disease(AD mice),VGLUT3→PGIs synaptic transmission is impaired by ETV4 inhibition of VGLUT3 transcription. ETV4 binds to a promoter region of VGLUT3 and activates VGLUT3 transcription in VGLUT3 neurons. Strengthening VGLUT3→PGIs synaptic transmission by ETV4 activation of VGLUT3 transcription upscales the efficacy of spatial memory retrieval in AD mice. This study reports a novel circuit and molecular mechanism underlying the efficacy of spatial memory retrieval via ETV4 inhibition of VGLUT3 transcription and hence provides a promising target for therapeutic intervention of the disease progression.展开更多
Background As the widespread use of electric devices in modern life, human are exposed to extremely low frequency magnetic fields （ELF MF） much more frequently than ever. Over the past decades, a substantial number ...Background As the widespread use of electric devices in modern life, human are exposed to extremely low frequency magnetic fields （ELF MF） much more frequently than ever. Over the past decades, a substantial number of epidemiological and experimental studies have demonstrated that ELF MF （50 Hz） exposure is associated with increased risk of various health effects. The present study examined the effects of chronic exposure to ELF MF on anxiety level and spatial memory of adult rats. Methods The 50-Hz ELF MF was used during the whole experimental procedures and the value of magnetic field （MF） was set to 2 mT. Adult rats were divided randomly to control, MF 1 hour and MF 4 hours group. Anxiety-related behaviors were examined in the open field test and the elevated plus maze; changes in spatial learning and memory were determined in Morris water maze aRer 4 weeks of daily exposure. Results Rats in MF 4 hours group had increased anxiety-like behaviors with unaltered locomotor activity. In the Morris water maze test, rats had reduced latency to find the hidden platform and improved long-term memory of former location of platform without changes in short-term memory and locomotor activity. Conclusion Chronic ELF MF exposure has anxiogenic effect on rats, and the promoting effects on spatial learning and long-term retention of spatial memory.展开更多
Propofol is widely used as an intravenous drug for induction and maintenance in general anesthesia.Hypoxemia is a common complication during perianesthesia.We want to know the effect of propofol on spatial memory and ...Propofol is widely used as an intravenous drug for induction and maintenance in general anesthesia.Hypoxemia is a common complication during perianesthesia.We want to know the effect of propofol on spatial memory and LTP(Long-term potentiation)under hypoxic conditions.In this study,84 seven-day-old SpragueeDawley rats were randomly assigned into six groups(n Z 14)-four control groups:lipid emulsion solvent t 50%oxygen(CO),lipid emulsion solvent t room air(CA),lipid emulsion solvent t 18%oxygen(CH),and propofol t 50%oxygen(propofoleoxygen,PO);and two experiment groups:propofol t room air(propofol eair,PA),and propofol t 18%oxygen(propofolehypoxia,PH).After receiving propofol(50 mg/kg)or the same volume of intralipid intraperitoneal(5.0 ml/kg),injected once per day for seven consecutive days,the rats were exposed to 18%oxygen,50%oxygen and air,until recovery of the righting reflex.We found that the apoptotic index and activated caspase-3 increased in the PH group(P<0.05)compared with the PA group,fEPSP(field excitatory postsynaptic)potential and success induction rate of LTP reduced in all propofol groups(P<0.05).Compared with the PO group,the fEPSP and success induction rate of LTP reduced significantly in the PA and PH groups(P<0.05).Moreover,compared with CH group,the average time of escape latency was longer,and the number of platform location crossings was significantly reduced in the PH group(P<0.05).Thus,we believe that adequate oxygen is very important during propofol anesthesia.展开更多
Although it has been suggested that olfaction is closely interconnected with hippocampal systems,whether olfaction regulates spatial memory strategy remains never known.Furthermore,no study has examined how olfaction ...Although it has been suggested that olfaction is closely interconnected with hippocampal systems,whether olfaction regulates spatial memory strategy remains never known.Furthermore,no study has examined how olfaction mediates spatial memory established on the external objects,for example,caches made by scatter-hoarding animals.Here,we experimentally induced nondestructive and reversible olfaction loss of a scatter-hoarding animal Leopoldamys edwardsi,to test whether and how olfaction regulates spatial memory to mediate cache recovery and pilferage.Our results showed that the normal L.edwardsi preferred to pilfer caches of others rather than to recover their own using accurate spatial memory(35.7%vs.18.6%).Anosmic L.edwardsi preferred to recover the caches they made prior to olfaction loss rather than to pilfer from others relied on spatial memory(54.2%vs.36.0%).However,L.edwardsi with anosmia showed no preference either to the caches they established after olfaction loss or caches made by others(25.8%vs.29.1%).These collectively indicate that olfaction loss has a potential to affect new memory formation but not previously established spatial memory on caches.Our study first showed that olfaction modified spatial memory strategy in cache recovery and pilferage behaviors of scatter-hoarding animals.We suggest that future studies pay more attention to the evolution of olfaction and its relationship with spatial memory strategy.展开更多
Autonomous navigation for intelligent mobile robots has gained significant attention,with a focus on enabling robots to generate reliable policies based on maintenance of spatial memory.In this paper,we propose a lear...Autonomous navigation for intelligent mobile robots has gained significant attention,with a focus on enabling robots to generate reliable policies based on maintenance of spatial memory.In this paper,we propose a learning-based visual navigation pipeline that uses topological maps as memory configurations.We introduce a unique online topology construction approach that fuses odometry pose estimation and perceptual similarity estimation.This tackles the issues of topological node redundancy and incorrect edge connections,which stem from the distribution gap between the spatial and perceptual domains.Furthermore,we propose a differentiable graph extraction structure,the topology multi-factor transformer(TMFT).This structure utilizes graph neural networks to integrate global memory and incorporates a multi-factor attention mechanism to underscore elements closely related to relevant target cues for policy generation.Results from photorealistic simulations on image-goal navigation tasks highlight the superior navigation performance of our proposed pipeline compared to existing memory structures.Comprehensive validation through behavior visualization,interpretability tests,and real-world deployment further underscore the adapt-ability and efficacy of our method.展开更多
BACKGROUND： Tetramethylpyrazine （TMP） presents the effect of anti-platelet aggregation, reduces arteria resistance, increases cerebral blood flow, and improves microcirculation. OBJECTIVE： To observe the effects o...BACKGROUND： Tetramethylpyrazine （TMP） presents the effect of anti-platelet aggregation, reduces arteria resistance, increases cerebral blood flow, and improves microcirculation. OBJECTIVE： To observe the effects of TMP on the learning and memory abilities and the number of neurons in cortex and hippocampus after focal cerebral ischemia in rats DESIGN： A randomized controlled tria SETTING： Department of Human Anatomy and Histological Embryology, School of Medicine, Xi＇an Jiaotong University. MATERIALS： Fifty adult male Sprague-Dawley rats, weighing 250-300 g were supplied by the Experimental Animal Center, School of Medicine, Xi＇an Jiaotong University. TMP was purchased from Wuxi Seventh Pharmaceutical Co.Ltd （Lot Number： 2004051106, Specification： 2 mL/piece）. METHODS ： The experiments were carried out in School of Medicine of Xi＇an Jiaotong University from June 2004 to May 2005. The 50 rats were randomly divided into five groups according to the random number table method： sham-operated group, cerebral ischemia control group, low-dose TMP group, middle-dose TMP group and high-dose TMP group, 10 rats in each group. Rats in the TMP groups were immediately treated with intraperitoneal injection of TMP of 40, 80 and 120 mg/kg respectively, and those in the sham-operated group and cerebral ischemia control group were injected intraperitoneally by isovolume saline, once a day for 14 days successively. On the 15^th day, the spatial learning and memory abilities of the rats were assessed with the Morris water maze test, and then the changes of neuron numbers in cortex and hippocampus were observed by Nissl staining of brain sections. MAIN OUTCOME MEASURES ： The results of Morris water maze test and the changes of neuron numbers in cortex and hippocampus by Nissl staining of brain sections were observed. RESULTS： Finally 39 rats were involved in the analysis of results, and the other 11 died of excessive anesthesia or failure in model establishment. ① The rats in the cerebral ischemia control group manifested obvious spatial cognitive deficits in the place navigation trial and spatial probe trial. The mean values of escape latency in the sham-operated group, low, middle and high-dose TMP groups were obviously shorter than that in the cerebral ischemia control group [（23.92±2.21）, （41.84±3.74）, （39.50 ±3.80）, （31.38_±3.72）, （61.60±3.61） s, P 〈 0.05-0.01]. In the spatial probe trial, significant differences in the percentage of time spending in the former platform quadrant and frequency of crossing the former platform site in the sham-operated group, lose, middle and high-dose TMP groups were obviously higher or more than those in the cerebral ischemia control group [（36.27±3.42） %, （35.84±2.54）%, （38.43±3.08）%, （36.51±1.96）%, （22.24±3.46）%; （11 ±1 ）, （10±1）, （8_±1）, （8±1）, （4±1） times, P 〈 0.01]. ② In the morphological observation, the numbers of neurons in ipsilateral （left） parietal cortex in the sham-operated group, low, middle and high-dose TMP groups were obviously more than that in the cerebral ischemia control group [（98±8）, （65±5）, （53±6）, （57±6）, （37±6）/0.625 mm^2, P 〈 0.01], but the number of neurons in left hippocampus had no obvious differences among the groups （P 〉 0.05）. CONCLUSION ： TMP can improve obviously the spatial learning and memory function after permanent focal cerebral ischemia in rats, and the neuroprotective role of the drug in cortex may be involved in its mechanism.展开更多
Chronic long-term exposure to cuprizone causes severe brain demyelination in mice,which leads to changes in locomotion,working memory and anxiety.These findings suggest the importance of intact myelin for these behavi...Chronic long-term exposure to cuprizone causes severe brain demyelination in mice,which leads to changes in locomotion,working memory and anxiety.These findings suggest the importance of intact myelin for these behaviors.This study aimed to investigate the possible behavioral changes in mice with mild oligodendrocyte/myelin damage that parallels the white matter changes seen in the brains of patients with psychiatric disporders.We used the cuprizonetreated mouse model to test both tissue changes and behavioral functions（locomotor activity,anxiety status,and spatial working memory）.The results showed that mice given cuprizone in their diet for 7 days had no significant myelin breakdown as evaluated by immunohistochemical staining for myelin basic protein,while the number of mature oligodendrocytes was reduced.The number and length of Caspr protein clusters,a structural marker of the node of Ranvier,did not change.The locomotor activity of the cuprizonetreated mice increased whereas their anxiety levels were lower than in normal controls;spatial working memory,however,did not change.These results,for the first time,link emotion-related behavior with mild white matter damage in cuprizone-treated mice.展开更多
BACKGROUND: Calcitonin gene-related peptide (CGRP) and nerve growth actor (NGF) cam improve spatial learning and memory abilities of rats with cerebral ischemia/reperfusion; however, the effect of combination of them ...BACKGROUND: Calcitonin gene-related peptide (CGRP) and nerve growth actor (NGF) cam improve spatial learning and memory abilities of rats with cerebral ischemia/reperfusion; however, the effect of combination of them on relieving learning and memory injury following cerebral ischemia/reperfusion should be further studied. OBJECTIVE: To study the effects of exogenous CGRP and NGF on learning and memory abilities of rats with focal cerebral ischemia/reperfusion. DESIGN: Randomized controlled animal study. SETTING: Department of Neurosurgery, the Second Hospital of Xiamen; Department of Neurosurgery, the Second Affiliated Hospital of China Medical University; Department of Neurobiology, Basic Medical College of China Medical University. MATERIALS: A total of 30 healthy male SD rats, aged 8 weeks, of clean grade, weighing 250-300 g, were provided by Experimental Animal Department of China Medical University. All rats were randomly divided into sham-operation group, ischemia/reperfusion group and treatment group with 10 in each group. The main reagents were detailed as the follows: 100 g/L chloral hydrate, 0.5 mL CGRP (2 mg/L, Sigma Company, USA), and NGF (1× 106 U/L, 0.5 mL, Siweite Company, Dalian). METHODS: The experiment was carried out in the Department of Neurobiology, Basic Medical College of China Medical University from February to July 2005. Rat models of middle cerebral artery occlusion were established by method of occlusion, 2 hours after that rats were anesthetized and the thread was slightly drawn out for 10 mm under direct staring to perform reperfusion. Rats in the ischemia/reperfusion group received intraperitoneal injection of 1 mL saline via the abdomen at two hours later, while rats in the treatment group at 2 hours later received intraperitoneal injection of 2 mg/L CGRP (0.5 mL) and 1×106 U/L NGF (0.5 mL) once a day for 10 successive days. First administration was accomplished within 15 minutes after ischemia/reperfusion. Rats in the sham-operation group were separated of the vessels without occlusion or administration. The neural function was evaluated with Zea Longa 5-grade scale. Animals with the score of one, two and three points received Morris water-maze test to measure searching time on platform (omitting platform-escaping latency). Meanwhile, leaning and memory abilities of animals were reflected through testing times of passing through platform per minute. MAIN OUTCOME MEASURES: Experimental results of omitting platform-escaping latency and spatial probe. RESULTS: Three and two rats in the ischemia/reperfusion group and treatment group respectively were not in accordance with the criteria in the process, and the rest were involved in the final analysis. ① Comparisons of platform-escaping latency during Morris water-maze test in all the three groups: Ten days after modeling, the platform-escaping latency in the ischemia/reperfusion group was obviously longer than that in sham-operation group (P < 0.01), and was significantly shorter than that in the treatment group (P < 0.01). ② Comparisons of times of passing through platform in all the three groups: Times of passing through platform were remarkably less in the ischemia/reperfusion group than those in the sham-operation group [(1.79±0.39), (4.30±0.73) times/minute, P < 0.01], and those were markedly more in the treatment group than the ischemia/reperfusion group [(3.16±1.03), (1.79±0.39) times/minute, P < 0.01]. CONCLUSION: CGRP and NGF are capable of ameliorating the abilities of spatial learning and memory in MCAO rats, which indicates that CGRP and NGF can protect ischemic neurons.展开更多
基金supported by the National Natural Science Foundation of China(NSFC,No30800102)Natural Science Foundation of Hainan Province(309026)
文摘In order to study the relationship between landmarks and spatial memory in short-nosed fruit bat, Cynopterus sphinx （Megachiroptera, Pteropodidae）, we simulated a foraging environment in the laboratory. Different landmarks were placed to gauge the spatial memory of C. sphinx. We changed the number of landmarks every day with 0 landmarks again on the fifth day （from 0, 2, 4, 8 to 0）. Individuals from the control group were exposed to the identical artificial foraging environment, but without landmarks. The results indicated that there was significant correlation between the time of the first foraging and the experimental days in both groups （Pearson Correlation： experimental group： r=-0.593, P〈0.01; control group： r=-0.581, P〈0.01）. There was no significant correlation between the success rates of foraging and the experimental days in experimental groups （Pearson Correlation： r=0.177, P〉0.05）, but there was significant correlation between the success rates of foraging and the experimental days in the control groups （Pearson Correlation： r=0.445, P〈0.05）. There was no significant difference for the first foraging time between experimental and control groups （GLM： F0.05,1=4.703, P〉0.05）; also, there was no significant difference in success rates of foraging between these two groups （GLM： F0.05,1=0.849,P〉0.05）. The results of our experiment suggest that spatial memory in C. sphinx was formed gradually and that the placed landmarks appeared to have no discernable effects on the memory of the foraging space.
基金supported by the National Major Science and Technology Program of China(2016YFC1306700)the National Natural Science Foundation of China(81420108012,81671046,81425010 and 31630031)+1 种基金the Jiangsu Provincial Medical Program for Distinguished Scholars(2016006)Postgraduate Research&Practice Innovation Program of Jiangsu Province(KYCX18_0167),China
文摘A deficit in spatial memory has been taken as an early predictor of Alzheimer’s disease(AD)or mild cognitive impairment(MCI).The uncinate fasciculus(UF)is a long-range white-matter tract that connects the anterior temporal lobe with the orbitofrontal cortex(OFC)in primates.Previous studies have shown that the UF impairment associated with spatial memory deficits may be an important pathological change in aging and AD,but its exact role in spatial memory is not well understood.The pathway arising from the postrhinal cortex(POR)and projecting to the ventrolateral orbitofrontal cortex(vlOFC)performs most of the functions of the UF in rodents.Although the literature suggests an association between spatial memory and the regions connected by the POR–vlOFC pathway,the function of the pathway in spatialmemory is relatively unknown.To further illuminate the function of the UF in spatial memory,we dissected the POR–vlOFC pathway in mice.We determined that the POR–vlOFC pathway is a glutamatergic structure,and that glutamatergic neurons in the POR regulate spatial memory retrieval.We also demonstrated that the POR–vlOFC pathway specifically transmits spatial information to participate in memory retrieval.These findings provide a deeper understanding of UF function and dysfunction related to disorders of memory,as in MCI and AD.
基金supported by a grant from the Natural Sciences Foundation of Jiangsu Province (No. BK2008081)the Scientific Research Fund of Nanjing Medical University (No. 2010NJMU244)
文摘Memantine is a N-methyl-D-aspartate (NMDA) receptor antagonist approved for the treatment of moderate to severe Alzheimer's disease (AD). Environmental enrichment (EE) has shown significant beneficial effects on func- tional improvement in AD. In this study, we sought to determine whether combining these two distinct therapies would yield greater benefit than either drug used alone. We investigated the effect of memantine combined with EE on spatial learning and memory and AD-like pathology in a widely used AD model, the senescence-accelerated prone mice (SAMP8). The SAMP8 mice were randomly assigned to enriched housing (EH) or standard housing (SH), where either memantine (20 mg/kg) or saline was given by gastric lavage once daily continuously for eight weeks. Our results showed that, when provided separately, memantine and EE significantly improved spatial learning and memory by shortening escape latencies and increasing the frequency of entrance into the target quadrant. When combined, memantine and EE showed additive effect on learning and memory as evidenced by significant shorter escape latencies and higher frequency of target entrance than either drug alone. Consistent with the behavior results, pathological studies showed that both memantine and EE significantly reduced hippocampal CA1 neurofibrilliary tangles (NFTs) as well as amyloid beta precursor protein (APP) levels. Combining both therapies synergistically lessened NFTs and APP expression compared to either drug alone in SAMP8 mice, indicating that the combination of memantine with EE could offer a novel and efficient therapeutic strategy for the treatment of AD.
基金a grant from the Substance Abuse and Dependence Research Center University of Social Welfare and Rehabilitation Sciences, No. 313-126417Tehran University of Medical Sciences, No. P/664
文摘3, 4-methylenedioxymethamphetamine （MDMA; also known as ＇ecstasy＇） has been shown to impair learning and spatial memory in adult and neonatal rats. Many studies have focused on the acute effects of MDMA on memory. In the present study, we intraperitoneally administered MDMA （0, 5, 10, 20 mg/kg） to adult male rats to investigate the effects of different doses on rat spatial memory in the Morris water maze, body temperature, and mortality, twice a day, for 7 successive days. The results indicated that MDMA impaired spatial memory dose-dependently, with the highest dose （20 mg/kg） exerting the strongest effects. In addition, MDMA also caused hyperthermia and increased mortality in rats
基金This program was supported by National Natural Science Foundation of China (No. 39830450)
文摘Objective: To observe the effect of Tiaoxin Recipe (TXR) on the spatial memory, brain mitochondrial energy metabolism of oxidation injured Alzheimer's disease (AD) rats, and to explore the mechanism of TXR in treating AD. Methods: Eighty-eight SD rats were randomly divided into five groups (normal group, operative group, "AD" model group,TXR group and Aricept group). An oxygen free radical generation system (dihydroxy fumaric acid-trichloroferric-adenosine diphosphate, DHF-FeCl3-ADP) was used to create oxidation injured rat models mimic to AD; spatial learning and memory impairment (Morris water maze method), the activity of Succinate-oxidase, NADH-oxidase, CytC-oxidase (Clark oxygen electrode method) and the expression of cytochrome oxidase (CO) II mRNA (in situ hybridization method) were observed. Results: Compared with the normal group, the spatial memory, activity of CytC-oxidase and COII mRNA expression of oxidation injured "AD" rats were obviously decreased; TXR, however, could improve these functions in "AD" rat models obviously. Conclusion: The mechanism of the action of TXR in treating AD was partly related to its effect on anti-oxidation which could improve brain mitochondrial energy metabolism.
基金supported by Natural Science Foundation of Shanghai(No.23ZR1401700)National Natural Science Foundation of China(Nos.12271088 and 11971143).
文摘In this paper,we introduce spatial memory into a predator–prey model with herd behavior.Taking memory-based diffusion coefficient and average memory period of predators as control parameters,we obtain the stable conditions of the positive equilibrium of system and prove the existence of Hopf bifurcation.In addition,a double Hopf bifurcation occurs at the intersection of the nonhomogeneous Hopf bifurcation curves,and a spatially nonhomogeneous quasi-periodic pattern can be observed near the double Hopf bifurcation point by numerical simulation.
基金the National Natural Science Foundation of China(No.91632103)the Shanghai Education Commission Research and Innovation Program(No.2019-01-07-00-02-E00037)+2 种基金the Program of Shanghai Subject Chief Scientist(No.17XD1401700)the Higher Education Disciplinary Innovation Programthe“Eastern Scholar”Project。
文摘Working memory is a core cognitive function that supports goal-directed behavior and complex thought.We developed a spatial working memory and attention test on paired symbols(SWAPS)which has been proved to be a useful and valid tool for spatial working memory and attention studies in the fields of cognitive psychology,education,and psychiatry.The repeated administration of working memory capacity tests is common in clinical and research settings.Studies suggest that repeated cognitive tests may improve the performance scores also known as retest effects.The systematic investigation of retest effects in SWAPS is critical for interpreting scientific results,but it is still not fully developed.To address this,we recruited 77 college students aged 18–21 years and used SWAPS comprising 72 trials with different memory loads,learning time,and delay span.We repeated the test once a week for five weeks to investigate the retest effects of SWAPS.There were significant retest effects in the first two tests:the accuracy of the SWAPS tests significantly increased,and then stabilized.These findings provide useful information for researchers to appropriately use or interpret the repeated working memory tests.Further experiments are still needed to clarify the factors that mediate the retest effects,and find out the cognitive mechanism that influences the retest effects.
基金supported by National Natural Science Foundation of China 12101318Natural Science Found of Jiangsu Province BK20200805 and Natural Science Fund Project of Colleges in Jiangsu Province 20KJB110009.
文摘This is an Open Access article published by World Scientific Publishing Company.It is distributed under the terms of the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0(CC BY-NC-ND)License,which permits use,distribution and reproduction,provided that the original work is properly cited,the use is non-commercial and no modifications or adaptations are made.The cognitive abilities of animals,such as memory,have a significant impact on their movement in space.In this paper,we consider a radio-dependent model with memorybased diffusion under the conditions of Neumann boundary.The stability of a positive equilibrium and the existence of the Turing-Hopf bifurcation induced by memory diffusion and memory delay are carried out in details.Notably,our findings indicate that with a relatively short average memory period,the large memory diffusion can stabilize an otherwise unstable equilibrium.In addition,the third-order truncated normal form for the Turing-Hopf bifurcation restricted to the central manifold is derived,which can reveal the generation of some steady-state and time-periodic solutions with spatial heterogeneity.The coefficients within the normal form are systematically determined through matrix operations,and these results can also be applied to other models with memory diffusion.Ultimately,leveraging the theoretical findings,we elucidated the intricate spatial-temporal dynamics and their associated parameter scopes caused by Turing-Hopf bifurcation through numerical simulations.
基金supported by the Russian science foundation(grant#22-74-00115 to A.P.G.).
文摘Background:Mitochondrial dysfunction plays a critical role in the pathogenesis of Alzheimer’s disease(AD).Resveratrol is a promising compound for the treatment of various neurodegenerative diseases,including AD.Aims:To investigate mitochondrial damage and the effects of resveratrol on inflammation,cognitive function,and mitochondrial quality control in APP/PS1 mice.Methods:Comparative analysis of mitochondrial DNA(mtDNA)damage was conducted between 10-month-old APP/PS1 mice and age-matched C57BL/6 mice.Assessments included measurement of amyloid-βlevels,inflammatory markers,swimming distance in the Morris water maze,and gut microbiome composition.Resveratrol’s effects on cytokine expression,mtDNA levels in plasma,and activation of Nuclear factor erythroid 2-related factor 2/Antioxidant response element(Nrf2/ARE)and phosphoinositide 3-kinase/protein kinase B(also known as Akt)/mechanistic target of rapamycin complex 1(PI3K/Akt/mTORC1)signaling pathways were also evaluated.Results:APP/PS1 mice exhibited significantly increased mtDNA damage in the prefrontal cortex,midbrain,and cerebellum,alongside higher amyloid-βlevels and inflammatory markers.Resveratrol treatment led to reduced expression of pro-inflammatory cytokines,a decrease in Proteobacteria levels,and lower cell-free mtDNA in plasma.Partial improvement in long-term spatial memory was observed in APP/PS1 mice following resveratrol treatment,likely due to its anti-inflammatory properties.Activation of the Nrf2/ARE signaling pathway and markers of PI3K/Akt/mTORC1 axis activation were noted,with the latter regulating long-term potentiation.Conclusion:Resveratrol demonstrates potential in mitigating inflammation and improving mitochondrial quality control in APP/PS1 mice,but it does not reduce amyloid-βlevels,highlighting the complexity of AD pathology and the need for further research.
文摘The relation between evolution of spatial working memory function and of morphology of the dorsolateral prefrontal cortex among the rhesus monkey (Macaca mulatta), the slow loris (Nycticebus coucang) and the tree shrew (Tupaia belangen chinensis) were reported in present paper. The results read as follows: In the DR performance with training, the rhesus monkeys and slow lorises could reach a criterion of 90% correct response at 1.1 ± 3.2 seconds, and 3.8±0.4 seconds delay interval, respectively, by 1000 training trails. The tree shrews failed to reach the criterion of 90% correct response even at 0 seconds delay interval by 1000 training trails. If a delay interval was tested in one session (30 trails) only, doing the DR performamce without training, the rhesus monkeys reached a correct of 80% or higher in each session at 0, 1, 2, 3, 4, and 5 seconds delay, respectively. The percent correct in each session of the slow lorises showed no differences from the rhesus monkeys at 0, 1, 2, 3, and 4 seconds delay. However, when the delay interval was increased to 5 seconds, the percent correct of the DR performance declined to 70% or lower in the slow lorises. In the tree shrews the percent correct in each session reached to 70% or lower at 0, 1, 2, 3, 4, and 5 seconds delay interval, respectively. The morphological studies revealed that the size of the prefrontal cortex increased, and the structure got complex in the course of the evolution in primates. It is suggested that the relation of evolution between the spatial working memory function and anatomy in the prefrontal cortex might be significant among the three species, both the development of morphology and that of the spatial working memory function in the dorsolateral prefrontal cortex are later than other regions of cerebral cortex in phylogenetic evolution course.
基金The project was supported by grants from the National Natural Science Foundation of China （No. 30271325） and the Major State Basic Resarch Development Program of China （＂973＂ Program） （No. 2005CB522604）.
文摘Background Human amniotic epithelial cells （HAECs）, which have characteristics of both embryonic and pluripotent stem cells, are therefore a candidate in cell therapy without creating legal or ethical problems. In the present study, we aimed to investigate the effects of intracerebroventricular transplantation of HAECs on doubly transgenic mice of Alzheimer＇s disease （AD） coexpressing presenilin-1 （PS1） and mutant Sweden amyloid precursor protein （APPswe） genes. Methods The offspring mice genotypes were detected using PCR identification of APPswe and PS1 gene. The doubly transgenic （TG） mice （n=20） and wild-type （WT） mice （n=20） were randomly divided into two groups respectively： the transplantation group treated with HAECs and the control group with phosphate buffered saline. Six radial arm water maze test was used to assess the spatial memory in the TG and WT mice. Amyloid plaques and neurofibrillary tangles were analyzed using congo red and acid-silver methenamine staining respectively. was used to track the survival of HAECs. Immunohistochemistry was used octamer-binding protein 4 （Oct-4） and Nanog in the HAECs. High performance measure acetylcholine in hippocampus. The density of cholinergic neurons in hippocampus was measured using acetylcholinesterase staining. Immunofluorescence cytochemistry to determine the expression of quid chromatography was used to basal forebrain and nerve fibers in Results Amyloid deposition occurred in hippocampus and frontal cortex in the double TG mice aged 8 months, but not in WT mice. The results also showed that transplanted HAECs can survive for at least 8 weeks and migrate to the third ventricle without immune rejection. The graft HAECs can also express the specific marker Oct-4 and Nanog of stem cell. Compared with the control group, transplantation of HAECs can not only significantly improve the spatial memory of the TG mice, but also increase acetylcholine concentration and the number of hippocampal cholinergic neurites. Conclusions These results demonstrate that intracerebroventricular transplantation of HAECs can improve the spatial memory of the double TG mice. The higher content of acetylcholine in hippocampus released by more survived cholinergic neurites is one of the causes of this improvement.
基金This work was supported in part by the National Natural Science Foundation of China(Grant Nos.39925012,30100057&30170221)Science and Technology Committee of China(G1999054007)National Educational Committee of China(2001-171).
文摘In Alzheimer抯 disease (AD), hyperphosphorylation of tau may be the underlying mechanism for the cytoskeletal abnormalities and neuronal death. It was reported that cy-clin-dependent kinase5 (cdk-5) could phosphorylate tau at most AD-related epitopes in vitro. In this study, we investigated the effect of cdk-5 overexpression on tau phosphorylation and spatial memory in rat. We demonstrated that 24 h after transfection into rat hippocampus, cdk-5 was overexpressed and induced a reduced staining with antibody tau-1 and an enhanced staining with antibodies 12e8 and PHF-1, suggesting hyperphosphorylation of tau at Ser199/202, Ser262/356 and Ser396/404 sites. Additionally, the cdk-5 transfected rats showed long latency to find the hidden platform in Morris water maze compared to the control rat. 48 h after transfection, the level of cdk-5 was decreased significantly, and the latency of rats to find the hidden platform was prolonged. It implies that in vivo overexpression of cdk-5 leads to impairment of spatial memory in rat and tau hyperphosphorylation may be the underlying mechanism.
基金supported by the National Natural Science Foundation of China (31721002, 81920208014, 31930051, 81800133)China Postdoctoral Science Foundation Funded Project (2018M642853)。
文摘The raphe nucleus is critical for feeding, rewarding and memory. However, how the heterogenous raphe neurons are molecularly and structurally organized to engage their divergent functions remains unknown. Here, we genetically target a subset of neurons expressing VGLUT3. VGLUT3 neurons control the efficacy of spatial memory retrieval by synapsing directly with parvalbumin-expressing GABA interneurons(PGIs) in the dentate gyrus. In a mouse model of Alzheimer's disease(AD mice),VGLUT3→PGIs synaptic transmission is impaired by ETV4 inhibition of VGLUT3 transcription. ETV4 binds to a promoter region of VGLUT3 and activates VGLUT3 transcription in VGLUT3 neurons. Strengthening VGLUT3→PGIs synaptic transmission by ETV4 activation of VGLUT3 transcription upscales the efficacy of spatial memory retrieval in AD mice. This study reports a novel circuit and molecular mechanism underlying the efficacy of spatial memory retrieval via ETV4 inhibition of VGLUT3 transcription and hence provides a promising target for therapeutic intervention of the disease progression.
文摘Background As the widespread use of electric devices in modern life, human are exposed to extremely low frequency magnetic fields （ELF MF） much more frequently than ever. Over the past decades, a substantial number of epidemiological and experimental studies have demonstrated that ELF MF （50 Hz） exposure is associated with increased risk of various health effects. The present study examined the effects of chronic exposure to ELF MF on anxiety level and spatial memory of adult rats. Methods The 50-Hz ELF MF was used during the whole experimental procedures and the value of magnetic field （MF） was set to 2 mT. Adult rats were divided randomly to control, MF 1 hour and MF 4 hours group. Anxiety-related behaviors were examined in the open field test and the elevated plus maze; changes in spatial learning and memory were determined in Morris water maze aRer 4 weeks of daily exposure. Results Rats in MF 4 hours group had increased anxiety-like behaviors with unaltered locomotor activity. In the Morris water maze test, rats had reduced latency to find the hidden platform and improved long-term memory of former location of platform without changes in short-term memory and locomotor activity. Conclusion Chronic ELF MF exposure has anxiogenic effect on rats, and the promoting effects on spatial learning and long-term retention of spatial memory.
基金This study was supported by the National Natural Science Foundation of China[31200853]Health Commission of Chongqing,China[2015HBRC007]+1 种基金Natural Science Foundation of Chongqing[cstc2012jjA10036]National Key Clinical Program([2013]544).
文摘Propofol is widely used as an intravenous drug for induction and maintenance in general anesthesia.Hypoxemia is a common complication during perianesthesia.We want to know the effect of propofol on spatial memory and LTP(Long-term potentiation)under hypoxic conditions.In this study,84 seven-day-old SpragueeDawley rats were randomly assigned into six groups(n Z 14)-four control groups:lipid emulsion solvent t 50%oxygen(CO),lipid emulsion solvent t room air(CA),lipid emulsion solvent t 18%oxygen(CH),and propofol t 50%oxygen(propofoleoxygen,PO);and two experiment groups:propofol t room air(propofol eair,PA),and propofol t 18%oxygen(propofolehypoxia,PH).After receiving propofol(50 mg/kg)or the same volume of intralipid intraperitoneal(5.0 ml/kg),injected once per day for seven consecutive days,the rats were exposed to 18%oxygen,50%oxygen and air,until recovery of the righting reflex.We found that the apoptotic index and activated caspase-3 increased in the PH group(P<0.05)compared with the PA group,fEPSP(field excitatory postsynaptic)potential and success induction rate of LTP reduced in all propofol groups(P<0.05).Compared with the PO group,the fEPSP and success induction rate of LTP reduced significantly in the PA and PH groups(P<0.05).Moreover,compared with CH group,the average time of escape latency was longer,and the number of platform location crossings was significantly reduced in the PH group(P<0.05).Thus,we believe that adequate oxygen is very important during propofol anesthesia.
基金provided by the National Natural Science Foundation of China(32070447,31760156)the Young Talents Invitation Program of Shandong Provincial Colleges and Universities(20190601)。
文摘Although it has been suggested that olfaction is closely interconnected with hippocampal systems,whether olfaction regulates spatial memory strategy remains never known.Furthermore,no study has examined how olfaction mediates spatial memory established on the external objects,for example,caches made by scatter-hoarding animals.Here,we experimentally induced nondestructive and reversible olfaction loss of a scatter-hoarding animal Leopoldamys edwardsi,to test whether and how olfaction regulates spatial memory to mediate cache recovery and pilferage.Our results showed that the normal L.edwardsi preferred to pilfer caches of others rather than to recover their own using accurate spatial memory(35.7%vs.18.6%).Anosmic L.edwardsi preferred to recover the caches they made prior to olfaction loss rather than to pilfer from others relied on spatial memory(54.2%vs.36.0%).However,L.edwardsi with anosmia showed no preference either to the caches they established after olfaction loss or caches made by others(25.8%vs.29.1%).These collectively indicate that olfaction loss has a potential to affect new memory formation but not previously established spatial memory on caches.Our study first showed that olfaction modified spatial memory strategy in cache recovery and pilferage behaviors of scatter-hoarding animals.We suggest that future studies pay more attention to the evolution of olfaction and its relationship with spatial memory strategy.
基金supported in part by the National Natural Science Foundation of China (62225309,62073222,U21A20480,62361166632)。
文摘Autonomous navigation for intelligent mobile robots has gained significant attention,with a focus on enabling robots to generate reliable policies based on maintenance of spatial memory.In this paper,we propose a learning-based visual navigation pipeline that uses topological maps as memory configurations.We introduce a unique online topology construction approach that fuses odometry pose estimation and perceptual similarity estimation.This tackles the issues of topological node redundancy and incorrect edge connections,which stem from the distribution gap between the spatial and perceptual domains.Furthermore,we propose a differentiable graph extraction structure,the topology multi-factor transformer(TMFT).This structure utilizes graph neural networks to integrate global memory and incorporates a multi-factor attention mechanism to underscore elements closely related to relevant target cues for policy generation.Results from photorealistic simulations on image-goal navigation tasks highlight the superior navigation performance of our proposed pipeline compared to existing memory structures.Comprehensive validation through behavior visualization,interpretability tests,and real-world deployment further underscore the adapt-ability and efficacy of our method.
基金the National Natural Science Foundation of China, No. 30170300 30300109
文摘BACKGROUND： Tetramethylpyrazine （TMP） presents the effect of anti-platelet aggregation, reduces arteria resistance, increases cerebral blood flow, and improves microcirculation. OBJECTIVE： To observe the effects of TMP on the learning and memory abilities and the number of neurons in cortex and hippocampus after focal cerebral ischemia in rats DESIGN： A randomized controlled tria SETTING： Department of Human Anatomy and Histological Embryology, School of Medicine, Xi＇an Jiaotong University. MATERIALS： Fifty adult male Sprague-Dawley rats, weighing 250-300 g were supplied by the Experimental Animal Center, School of Medicine, Xi＇an Jiaotong University. TMP was purchased from Wuxi Seventh Pharmaceutical Co.Ltd （Lot Number： 2004051106, Specification： 2 mL/piece）. METHODS ： The experiments were carried out in School of Medicine of Xi＇an Jiaotong University from June 2004 to May 2005. The 50 rats were randomly divided into five groups according to the random number table method： sham-operated group, cerebral ischemia control group, low-dose TMP group, middle-dose TMP group and high-dose TMP group, 10 rats in each group. Rats in the TMP groups were immediately treated with intraperitoneal injection of TMP of 40, 80 and 120 mg/kg respectively, and those in the sham-operated group and cerebral ischemia control group were injected intraperitoneally by isovolume saline, once a day for 14 days successively. On the 15^th day, the spatial learning and memory abilities of the rats were assessed with the Morris water maze test, and then the changes of neuron numbers in cortex and hippocampus were observed by Nissl staining of brain sections. MAIN OUTCOME MEASURES ： The results of Morris water maze test and the changes of neuron numbers in cortex and hippocampus by Nissl staining of brain sections were observed. RESULTS： Finally 39 rats were involved in the analysis of results, and the other 11 died of excessive anesthesia or failure in model establishment. ① The rats in the cerebral ischemia control group manifested obvious spatial cognitive deficits in the place navigation trial and spatial probe trial. The mean values of escape latency in the sham-operated group, low, middle and high-dose TMP groups were obviously shorter than that in the cerebral ischemia control group [（23.92±2.21）, （41.84±3.74）, （39.50 ±3.80）, （31.38_±3.72）, （61.60±3.61） s, P 〈 0.05-0.01]. In the spatial probe trial, significant differences in the percentage of time spending in the former platform quadrant and frequency of crossing the former platform site in the sham-operated group, lose, middle and high-dose TMP groups were obviously higher or more than those in the cerebral ischemia control group [（36.27±3.42） %, （35.84±2.54）%, （38.43±3.08）%, （36.51±1.96）%, （22.24±3.46）%; （11 ±1 ）, （10±1）, （8_±1）, （8±1）, （4±1） times, P 〈 0.01]. ② In the morphological observation, the numbers of neurons in ipsilateral （left） parietal cortex in the sham-operated group, low, middle and high-dose TMP groups were obviously more than that in the cerebral ischemia control group [（98±8）, （65±5）, （53±6）, （57±6）, （37±6）/0.625 mm^2, P 〈 0.01], but the number of neurons in left hippocampus had no obvious differences among the groups （P 〉 0.05）. CONCLUSION ： TMP can improve obviously the spatial learning and memory function after permanent focal cerebral ischemia in rats, and the neuroprotective role of the drug in cortex may be involved in its mechanism.
基金supported by the Manitoba Health Research Council Foundationthe Canadian Institutes of Health Research Foundationthe Health Science Centre Foundation
文摘Chronic long-term exposure to cuprizone causes severe brain demyelination in mice,which leads to changes in locomotion,working memory and anxiety.These findings suggest the importance of intact myelin for these behaviors.This study aimed to investigate the possible behavioral changes in mice with mild oligodendrocyte/myelin damage that parallels the white matter changes seen in the brains of patients with psychiatric disporders.We used the cuprizonetreated mouse model to test both tissue changes and behavioral functions（locomotor activity,anxiety status,and spatial working memory）.The results showed that mice given cuprizone in their diet for 7 days had no significant myelin breakdown as evaluated by immunohistochemical staining for myelin basic protein,while the number of mature oligodendrocytes was reduced.The number and length of Caspr protein clusters,a structural marker of the node of Ranvier,did not change.The locomotor activity of the cuprizonetreated mice increased whereas their anxiety levels were lower than in normal controls;spatial working memory,however,did not change.These results,for the first time,link emotion-related behavior with mild white matter damage in cuprizone-treated mice.
文摘BACKGROUND: Calcitonin gene-related peptide (CGRP) and nerve growth actor (NGF) cam improve spatial learning and memory abilities of rats with cerebral ischemia/reperfusion; however, the effect of combination of them on relieving learning and memory injury following cerebral ischemia/reperfusion should be further studied. OBJECTIVE: To study the effects of exogenous CGRP and NGF on learning and memory abilities of rats with focal cerebral ischemia/reperfusion. DESIGN: Randomized controlled animal study. SETTING: Department of Neurosurgery, the Second Hospital of Xiamen; Department of Neurosurgery, the Second Affiliated Hospital of China Medical University; Department of Neurobiology, Basic Medical College of China Medical University. MATERIALS: A total of 30 healthy male SD rats, aged 8 weeks, of clean grade, weighing 250-300 g, were provided by Experimental Animal Department of China Medical University. All rats were randomly divided into sham-operation group, ischemia/reperfusion group and treatment group with 10 in each group. The main reagents were detailed as the follows: 100 g/L chloral hydrate, 0.5 mL CGRP (2 mg/L, Sigma Company, USA), and NGF (1× 106 U/L, 0.5 mL, Siweite Company, Dalian). METHODS: The experiment was carried out in the Department of Neurobiology, Basic Medical College of China Medical University from February to July 2005. Rat models of middle cerebral artery occlusion were established by method of occlusion, 2 hours after that rats were anesthetized and the thread was slightly drawn out for 10 mm under direct staring to perform reperfusion. Rats in the ischemia/reperfusion group received intraperitoneal injection of 1 mL saline via the abdomen at two hours later, while rats in the treatment group at 2 hours later received intraperitoneal injection of 2 mg/L CGRP (0.5 mL) and 1×106 U/L NGF (0.5 mL) once a day for 10 successive days. First administration was accomplished within 15 minutes after ischemia/reperfusion. Rats in the sham-operation group were separated of the vessels without occlusion or administration. The neural function was evaluated with Zea Longa 5-grade scale. Animals with the score of one, two and three points received Morris water-maze test to measure searching time on platform (omitting platform-escaping latency). Meanwhile, leaning and memory abilities of animals were reflected through testing times of passing through platform per minute. MAIN OUTCOME MEASURES: Experimental results of omitting platform-escaping latency and spatial probe. RESULTS: Three and two rats in the ischemia/reperfusion group and treatment group respectively were not in accordance with the criteria in the process, and the rest were involved in the final analysis. ① Comparisons of platform-escaping latency during Morris water-maze test in all the three groups: Ten days after modeling, the platform-escaping latency in the ischemia/reperfusion group was obviously longer than that in sham-operation group (P < 0.01), and was significantly shorter than that in the treatment group (P < 0.01). ② Comparisons of times of passing through platform in all the three groups: Times of passing through platform were remarkably less in the ischemia/reperfusion group than those in the sham-operation group [(1.79±0.39), (4.30±0.73) times/minute, P < 0.01], and those were markedly more in the treatment group than the ischemia/reperfusion group [(3.16±1.03), (1.79±0.39) times/minute, P < 0.01]. CONCLUSION: CGRP and NGF are capable of ameliorating the abilities of spatial learning and memory in MCAO rats, which indicates that CGRP and NGF can protect ischemic neurons.
