Efecto del estímulo masticatorio y estrés agudo sobre la interleuquina 6, la memoria y el aprendizaje espacial en ratones Balb/c

Introducción. El estrés agudo altera la memoria y aprendizaje espacial y la expresión de la interleuquina 6 (IL-6), mientras que el estímulo masticatorio evitaría dichos efectos. Objetivo. Determinar el efecto del estímulo masticatorio y el estrés agudo sobre la expresión de interleuquina 6, la memoria y el aprendizaje espacial en ratones. Métodos. Experimento con 70 ratones albinos machos de 2 meses de edad de la cepa Balb/c que fueron distribuidos aleatoriamente en grupo A1: estrés agudo 1 hora; grupo A2: estrés agudo 1 hora + estímulo masticatorio 1 hora; grupo B1: estrés agudo 2 horas; grupo B2: estrés agudo 2 horas + estímulo masticatorio 2 horas; grupo C1: estrés agudo 3 horas; grupo C2: estrés agudo 3 horas + estímulo masticatorio 3 horas; y grupo D: sin intervención. Durante 3 días, se evaluó la memoria y el aprendizaje espacial en el laberinto acuático de Morris. La IL-6 fue determinada mediante ELISA. Resultados. La IL-6 fue mayor en el grupo B2 vs los demás grupos (p < 0,001). Además, en el primer día de evaluación, la adquisición de memoria y aprendizaje espacial fue menor en el grupo A1 vs A2 (p = 0,042). Conclusión. Solo en el primer día de evaluación encontramos que el estímulo masticatorio previno la disminución de la adquisición de memoria y aprendizaje espacial en ratones sometidos a estrés agudo de baja intensidad. Los resultados en general no fueron concluyentes sobre el efecto del estímulo masticatorio. Además, la IL-6 fue mayor en el estrés + el estímulo masticatorio (grupo B2) sobre el resto.

Introduction. Acute stress alters memory and spatial learning and the expression of interleukin 6, the chewing stimulus would prevent these effects. Objective. To determine the effect of chewing stimulation and acute stress on the expression of interleukin 6 and memory and spatial learning in mice. Methods. Experiment where 70 male albino mice of the Balb/c of age 2 month were randomly distributed into: Group A1: acute stress 1 hour; Group A2: acute stress 1 hour + chewing stimulus 1 hour; Group B1: acute stress 2 hours; Group B2: acute stress 2 hours + chewing stimulus 2 hours; Group C1: acute stress 3 hours; C2: acute stress 3 hours + chewing stimulus 3 hours; Group D: without intervention. For 3 days, spatial memory and learning were tested in the Morris water maze. Interleukin 6 (IL-6) was analyzed by ELISA test. Results. IL-6 was higher in the B2 group vs the other groups (p<0.0001). In addition, on the first day of evaluation, the acquisition of spatial memory and spatial was lower in the A1 vs. A2 group (p=0.042). Conclusión. Only on the first day of evaluation, we found that the masticatory stimulus prevented the decrease in memory acquisition and spatial learning in mice subjected to low-intensity acute stress. The results were generally inconclusive on the effect of masticatory stimulation. In addition, IL-6 was higher in the stress + masticatory stimulus (group B2) over the rest.

Subchronic Administration of High-dose Monosodium Glutamate Causes Spatial Memory Dysfunction and Structural Deficits of Rat Hippocampus

@#Introduction: The toxicity of high concentration monosodium glutamate (MSG) has become a controversial issue because of its inconsistent results in human and animal studies. This present study aims to evaluate the effect of subchronic high-doses oral administration of MSG on spatial memory performance and hippocampal pyramidal cells number. Methods: This study involved twenty-eight male Wistar rats, which were divided into a control group of NaCl 0.9% and three intervention groups of MSG 1.0 mg/g bodyweight (M1), 2.0 mg/g bodyweight (M2), and 4.0 mg/g bodyweight (M3) for 30 days. Statistical analysis used a One-way ANOVA test. Results: The result showed significant differences in spatial memory on the Morris Water Maze (MWM) test, including path length (p = 0.020) and escape latency (p = 0.011) according to general linear model repeated measurement analysis. The mean difference of estimated hippocampal pyramidal cells total number among the groups showed volume (p = 0.001), numerical density (p = 0.590), and cells number (p = 0.004). Furthermore, Post-Hoc analysis in both spatial memory and hippocampal pyramidal cells showed that the increasing MSG dose from 1.0 to 4.0 mg/g bodyweight led to a decrease in the results of spatial memory performance on the MWM test and a decrease in hippocampal cells. Conclusion: The present study has provided novel quantitative data that subchronic administration of high-dose MSG caused deleterious effects on the spatial memory function and the volume and number of hippocampal pyramidal cells.

Blue velvet arena test to detect spatial memory in patients with chronic insomnia disorder: a clinical study / 中华神经科杂志

Objective:To investigate the feasibility of blue velvet arena test (BVAT) in evaluating spatial memory function in patients with chronic insomnia disorder (CID).Methods:From June 1, 2021 to May 31, 2022, 62 CID outpatients or inpatients were enrolled continuously in the Department of Sleep Disorders, the Affiliated Chaohu Hospital of Anhui Medical University, and 56 good sleepers in the same period were enrolled to serve as controls. Pittsburgh Sleep Quality Index (PSQI) was used to assess their sleep quality. Montreal Cognitive Assessment Scale (MoCA), nine box maze test (NBMT), and BVAT were used to assess general cognition and memories.Results:Compared to the controls, the CID patients had increased PSQI score [15.0 (12.8, 16.0) vs 0 (0, 1.0); Z=-9.47, P<0.001], and decreased MoCA score [24.5 (21.5, 27.0) vs 27.0 (26.0, 28.0); Z=-4.18, P<0.001]; increased numbers of errors in the spatial working [1.0 (0.8, 2.0) vs 1.0 (0, 1.0); Z=-2.24, P<0.05], object working [1.5 (0.8, 3.0) vs 0 (0, 1.0); Z=-4.36, P<0.001] and object recognition [0 (0, 0) vs 0 (0, 0); Z=-2.10, P<0.05] memories in NBMT; and increased average erroring distance in BVAT [23.0 (16.4, 27.2) cm vs 18.7 (16.6, 20.7) cm; Z=-3.30, P<0.01]. Partial correlation analysis showed that in the CID patients, the average erroring distance in BVAT was positively correlated with erroneous numbers in spatial working memory in NBMT ( r=0.54, P<0.001). Principal components analysis showed that the average erroring distance of BVAT (load=0.844) and the errors of spatial working memory in NBMT (load=0.801) were jointly attributed to the first factor. Receiver operating characteristic curve analysis showed that the sensitivity of BVAT was higher than that of NBMT (0.575 vs 0.250, P<0.05) for spatial memory detection in total sample. Conclusion:The BVAT has a higher reliability in the functional assessment of spatial memory in CID patients.

N,N-dimethyltryptamine,a natural psychedelic,rap-idly improves spatial memory and hippocampal long-term potentiation:a potential rapid-acting therapy for dementia-associated wandering / 中国药理学与毒理学杂志

There is no fast-acting treatment strate-gies against Alzheimer's disease(AD),in particular dementia-related wandering.N,N-dimethyltryptamine(DMT)is a natural psychedelic that may have rapid-onset nootropic effects.In this study,5×FAD transgenic mice which recapitulated amyloid neuropathological features of AD received one single injection of 6 or 12 mg·kg-1 DMT and tested at 0.5,1,and 2 h thereafter in Y-maze for spatial memory.5×FAD transgenic mice exhibited pro-nounced decreases in time spent,number entered,and distance travelled in the novel arm of Y-maze.DMT at 12 mg·kg-1 partially or completely reversed the three behavioral indices at multiple time points,up to 2 h post injection.The rapid-onset behavioral improvement was consistent with pharmacokinetic analysis of DMT,showing approximately 30 min to reach the maximum concentra-tion in the brain tissue.The transgenic mice also displayed dramatically impaired hippocampal long-term potentiation(LTP),an electrophysiological feature of memory forma-tion and consolidation.DMT potently enhanced LTP and restored intracellular calcium activity,expression and phosphorylation of calcium/calmodulin-dependent protein kinase Ⅱ(CaMK Ⅱ)and AMPA-type glutamate receptor 1(GluR1),the two key calcium-activated mediators involved in LTP induction.Adenosine triphosphate(ATP)is purinergic signalling molecules that are involved in LTP induction and maintenance.DMT rapidly increased mito-chondrial ATP dynamics in in vivo and in vitro models.These results suggest that DMT rapidly improve spatial memory and hippocampal LTP by restoring the CaMK Ⅱ-GluR1 signaling pathway and mitochondrial ATP produc-tion.It may be served as a fast-acting nootropic agent for the treatment of AD in particular wandering.

The clinical symptoms and neurocognitive impairment of first-episode deficit and nondeficit subtype of schizophrenia / 中华行为医学与脑科学杂志

Objective:To ulteriorly explore the differences of psychotic symptoms and neurocognitive between patients with first-episode deficit subtype of schizophrenia (FDS) and patients with first-episode nondeficit subtype of schizophrenia (FNDS).Methods:From January 2021 to September 2021, a total of 88 first-episode treatment-naive schizophrenia were recruited from the Mental Health Center of West China Hospital and divided into FDS group( n=44) and FNDS group( n=44) according to the schedule for the deficit syndrome (SDS), and 44 healthy subjects were included as healthy control group (HC group, n=44). Positive and negative syndrome scale (PANSS) was used to assess psychotic symptoms of patients and Wechsler adult intelligence scale, trail making test and logic memory test were used to evaluate intelligence quotient and neurocognitive function of all subjects.SPSS 22.0 was used for statistical analysis, and independent samples t-test and one-way analysis of variance (ANOVA) were used to compare variables that met normal distribution, while the Mann-Whitney U test and Kruskal-Wallis H test were used to compare variables that did not meet normal distribution. Results:(1) There were significant differences in psychotic symptoms between the FDS group and the FNDS group.Compared with the FNDS group, the FDS group had higher total score of PANSS ((95.95±16.82) vs (88.39±16.29)), negative symptoms ((27.57±7.52) vs (16.57±5.76)) and anergastic reaction ((13.43±3.82) vs (7.00(5.00, 9.00)), and lower positive symptoms scores ((21.95±6.88) vs (25.41±6.07)), activation ((8.00(5.00, 9.00) vs (9.27±3.47)), depression ((5.50(4.00, 9.00) vs (8.00(6.00, 12.00)) and supplementary item ((13.60±4.17) vs (17.30±5.39))(all P<0.05). (2) There were differences in neurocognitive functions between FDS group and FNDS group, and which in FDS and FNDS group were worse than that in HC group.Spatial memory (block design test: (23.70±11.05) vs (31.72±11.49)) and information processing speed (digit symbol test: (38.38±15.85) vs (47.97±14.99)) of FDS group were significantly lower than those of FNDS group(both P<0.05). Intelligence quotient, information processing speed and spatial memory of FDS group and FNDS group were lower than those of HC group(all P<0.05). Conclusion:FDS patients has more severe negative symptoms and anergastic reaction, and exit worse information processing speed and spatial memory dysfunction than FNDS patients.This unique pattern of impairment suggests that information processing speed and spatial memory may be important classification indicators for differentiating the deficit subtype of schizophrenia in the early stage.

Effects of working memory training on cognition in healthy older adults: A systematic review / Efeitos do treino de memória operacional na cognição de idosos saudáveis: um estudo de revisão sistemática

ABSTRACT. The working memory (WM) training in older adults can benefit their cognition. However, there is a dearth of literature reviews on the subject. Objective: This study aimed to investigate and evaluate the effects of WM training on the cognition of healthy older adults, in individual and group interventions reported in the literature. Methods: This is a systematic review involving a qualitative analysis of publications on the SciELO, LILACS, and MEDLINE databases carried out between March and June 2021. Results: A total of 47 studies were identified and analyzed, comprising 40 in older adults only and 7 comparing older and younger adults, investigating individual or group WM training or other types of intervention focused on WM effects. Conclusions: Both individual and group intervention contributed to the maintenance and/or improvement of cognition in older adults exploiting brain plasticity to promote mental health and prevent cognitive problems that can negatively impact quality of life of this group.

RESUMO. O treino da memória operacional (WM) com idosos pode gerar benefícios em sua cognição. Entretanto, há escassez de revisões da literatura sobre o tema. Objetivo: Investigar e avaliar, na literatura, os efeitos do treino da WM na cognição de idosos saudáveis, em intervenções individuais e grupais. Métodos: Estudo de revisão sistemática realizado entre março e junho de 2021, utilizando-se as bases Scientific Electronic Library Online (SciELO), Literatura Latino-Americana e do Caribe em Ciências da Saúde (LILACS) e Medical Literature Analysis and Retrieval System Online (MEDLINE). Resultados: Foram identificados e analisados 47 estudos, 40 apenas com idosos, e sete comparativos entre idosos e adultos mais jovens, que realizaram treino individual ou em grupo com foco nos efeitos na WM. Conclusões: Os trabalhos analisados mostraram que ambos os tipos de intervenções podem contribuir para a manutenção e/ou melhoria da cognição de pessoas idosas, aproveitando sua plasticidade cerebral e, portanto, para a promoção de sua saúde mental e para a prevenção de problemas cognitivos que podem interferir em sua qualidade de vida.

Effect of providing purple sweet potato water extract on tumor necrosis factor-α levels, protein 53 expression, glial fibrillary acidic protein expression, brain-derived neurotrophic factor levels, and spatial working memory in rats with d-galactose induction / Efeito do extrato de água de batata doce roxo no fator de necrose tumoral níveis alfa, na expressão da proteína 53, na expressão de proteína ácida fibrilar glial, nos níveis de fator neurotrófico cerebral e na memória espacial em ratos com indução de d-galactose

ABSTRACT. Alzheimer's dementia (AD) is a neurodegenerative disease. The mechanism of oxidative stress in AD is due to amyloid beta (Aβ) protein that aggregates to form plaques, which further triggers chronic inflammation and neuronal apoptosis. Purple sweet potato extract with the main content of anthocyanins is a potential antioxidant with a direct target on the amyloid cascade hypothesis. Objective: The research objective was to determine the role of purple sweet potato water extract as an antioxidant and anti-inflammatory in preventing apoptosis in order to provide a neuroprotective effect in d-galactose-induced rats. Methods: A total of 100 male Wistar rats with randomized posttest-only control group design that met the eligibility criteria were included in this study. The treatment group was given 200 mg/kg BW/day of purple sweet potato water extract on days 1-70. d-galactose induction was administered in the treatment and control groups on days 15-70. Results: The independent t-test showed that the mean tumor necrosis factor-α (TNF-α) levels in the treatment group (735.36±139.74) was significantly lower than that in the control group (896.77±152.52). The p53 and glial fibrillary acidic protein (GFAP) expressions of astrocyte cells in the treatment group were significantly lower than that in the control group. The brain-derived neurotrophic factor (BDNF) levels in the treatment group (498.13±121.47) were higher than that in the control (391.93±140.28), and there was a significant increase in spatial working memory in the treatment group (72.01±10.22) than the control (59.77±11.87). Conclusions: The neuroprotective effect of purple sweet potato extract is due to d-galactose induction resulting from decrease in TNF-α levels, p53 expression, and GFAP expression and increase in BDNF levels and spatial working memory.

RESUMO. A doença de Alzheimer (DA) é uma doença neurodegenerativa. O mecanismo de estresse oxidativo na DA ocorre devido à proteína beta amilóide que se agrega para formar placas que desencadeiam inflamação crônica e apoptose neuronal. O extrato de batata-doce roxa composto principalmente por antocianinas é um potencial antioxidante com efeito direto sobre a hipótese da cascata amilóide. Objetivo: O objetivo da pesquisa foi determinar o papel do extrato aquoso de batata-doce roxa como antioxidante e anti-inflamatório na prevenção da apoptose, para proporcionar um efeito neuroprotetor em ratos induzidos por D-galactose. Métodos: Grupo controle randomizado pós-teste com 100 ratos Wistar machos que preencheram os critérios de elegibilidade. O grupo de tratamento recebeu 200mg/kg de peso corporal/dia de extrato aquoso de batata-doce roxa nos dias 1-70. A indução de D-galactose foi testada nos grupos de tratamento e controle nos dias 15-70. Resultados: O teste t independente mostrou que a média dos níveis de TNF-α no grupo de tratamento (735,36±139,74) foi significativamente menor do que no grupo controle (896,77±152,52). A expressão de p53 e a expressão de GFAP de células de astrócitos foram significativamente menores no grupo de tratamento do que no grupo controle. Os níveis de BDNF no grupo de tratamento (498,13±121,47) foram maiores que no grupo controle (391,93±140,28) e houve um aumento significativo da memória de trabalho espacial no grupo de tratamento (72,01±10,22) em relação ao controle (59,77±11,87). Conclusões: O efeito neuroprotetor do extrato de batata-doce roxa é devido à indução de D-galactose pela diminuição dos níveis de TNF-α, expressão de p53 e expressão de GFAP, aumentando assim os níveis de BDNF e memória espacial.

Efecto de Spirulina maxima sobre la memoria espacial en Rattus norvegicus var. albinus / Effect of Spirulina maxima on spatial memory in Rattus norvegicus var. albinus

RESUMEN Introducción: La memoria es un proceso fisiológico que se activa por estímulos externos, es necesaria para modificar la conducta, adaptación al medio y la diferenciación del modelo animal. Este proceso complejo que involucra no sólo a las redes sinápticas sino otros mecanismos neurofisiológicos, suele ser estimulado por algunos nutraceúticos. Objetivo: Evaluar el efecto de Spirulina maxima sobre la memoria espacial en Rattus norvegicus var. albinus Material y Métodos: Se desarrolló un diseño de estímulo creciente donde se ordenaron cuatro grupos con 5 ratas cada uno, se agruparon en grupos Tratamiento I, II y III; a los que se les dio por vía oral Spirulina maxima a diferentes concentraciones y el grupo testigo sin tratamiento, se valoró la memoria espacial en el laberinto acuático de Morris. Resultados: Las ratas presentaron un tiempo de latencia equivalente para desarrollar la fase de adquisición y de retención, se registraron tiempos promedio; al aplicar la dosis 200 y 400 mg/kg no varían los índices de aprendizaje entre sí; y ante la dosis de concentración más alta 800 mg/kg se observó una disminución leve del tiempo de latencia de la fase de adquisición. De acuerdo con la prueba ANOVA hubo poca diferencia. Conclusiones: Hubo efecto de la Spirulina maxima en la memoria espacial del sujeto experimental, evidenciable en la duración de la conducta motora en el laberinto acuático de Morris, a través de índices de aprendizaje los cuales presentaron modificación favorable.

ABSTRACT Introduction: Memory is a physiological process that is activated by external stimuli. It is necessary for behavior modification, adaptation to the environment, and differentiation in the animal model. This complex process that involves not only synaptic networks but other neurophysiological mechanisms, is usually stimulated by some nutraceuticals. Objective: To evaluate the effect of Spirulina maxima on spatial memory in Rattus norvegicus var. albinus. Material and Methods: An increasing stimulus design was developed. Four similar groups of 5 rats were arranged and grouped into treatment I, II and III groups which were given Spirulina maxima orally at different concentrations; the control group did not received treatment. Spatial memory was assessed using the Morris water maze. Results: The rats presented an equal latency time to develop the acquisition and the retention phases; average times were recorded; the learning rates did not differ from each other at doses of 200 and 400 mg / kg; at the highest concentration dose of 800 mg / kg, there was a slight decrease in the latency time during the acquisition phase. There was a slight difference according to the ANOVA test. Conclusions: There was an effect of Spirulina maxima on the spatial memory of the experimental subject, which was evident in the duration of the motor behavior in the Morris water maze through learning rates which presented a favorable modification.

Vitamin D3 mediates spatial memory improvement through nitric oxide mechanism in demyelinated hippocampus of rat

Abstract Studies have revealed beneficial role of vitamin D3 in neuro-cognitive function. There is also supporting evidence on the involvement of nitric oxide (NO) in the neuro-protective action. However, its over production could contribute to brain disorders. In this study, demyelination was induced by ethidium bromide (EB) injection into the right side of the hippocampus area of male rats. Vitamin D3 was administered to rats for 7 and 28 days prior to behavioral experiments using Morris water maze (MWM). Travelled distance, time spent to reach the platform, and time spent in target zone, were considered for learning and spatial memory evaluation. Nitrite oxide (NO2-) concentration was measured as an indicator for nitric oxide production. The time spent to reach the platform and the travelled distance were decreased significantly by 28 days of vitamin D3 administration (compared to 7 days experiment). Time spent in target quadrant was significantly lowered by administered vitamin on day 28. Therefore, considering a number of studies that have shown the effect of vitamin D3 on cognition, these findings could support their potential effect. Besides, nitric oxide concentration significantly differed in 28 days of vitamin D3 treated group compared with the groups treated with EB or 7 days of vitamin D3.

Effects of activated microglia in the prefrontal cortex on long-term spatial memory function in mice with post-stroke depression / 中华行为医学与脑科学杂志

Objective:To investigate the effect of activation of microglia in prefrontal cortex on long-term spatial memory in post-stroke depression mice.Methods:Forty-eight male C57BL/6 mice were divided into sham operation group, stroke group, post-stroke depression group and depression group according to the random number table method with 12 in each group, and 36 mice were divided into solvent group, enrofloxacin group and minocycline group according to the random number table method with 12 in each group.Middle cerebral artery occlusion (MCAO) was use to establish the stroke model, and forced swimming was used to establish the depression model.The post-stroke depression model mice were received MCAO first and then received forced swimming on the 4th day after stroke to establish the model.Mice in enrofloxacin group and minocycline group were treated with enrofloxacin and minocycline injection once a clay for 14 days from the 5th day after stroke, respectively.Forced swimming test and sugar water preference test were used to evaluate the depression of mice in each group, Morris water maze test was used to detect the spatial memory function of mice in each group, and Nissl staining and immunofluorescence staining were used to detect the neuronal function and the number and type of microglia activation.The expression of inflammatory cytokines IL-6 and IL-1β were detected by Western blot.GraphPad Prism 8.0.1 statistical software was used for statistical analysis.The single factor variance analysis was used to compare the difference among multiple groups, and pairwise comparison was performed with SNK- q test. Results:(1) There were statistically significant differences in depression, learning and memory, neuron damage, activation of microglia, inflammatory factors and other indicators in sham operation group, stroke group, post-stroke depression group and depression group ( F=43.58-255.70, all P<0.05). Compared with stroke group, post-stroke depression group had longer floating immobility time ((222.70±29.12) s, (79.25±46.78) s, P<0.05), the preference rate of sugar water was significantly lower ( (49.44±6.19) %, (84.49±4.73) %, P<0.05), and the average value of platform approach after correction was higher((125.00±9.95) mm, (96.79±12.57) mm, P<0.05), Nissl bodies expression was lower ((53.50±15.78) cells /mm 2, (85.67±17.52) cells /mm 2, P<0.05), NeuN positive expression rate was lower ((29.78±3.70) %, (45.73±4.51) %, P<0.05), the percent of M1 microglia expression was significantly higher ((75.55±8.84) %, (58.19±5.69) %, P<0.05), the percent of M2 microglia expression was lower ((43.46±5.11)%, (57.14±5.40)%, P<0.05), and the expression levels of IL-6 ((1.14±0.03), (0.94±0.05), P<0.05) and IL-1β((1.17±0.03), (0.56±0.04), P<0.05) were significantly higher.(2) Depression, learning and memory, neuron injury, activation of microglia, inflammatory factors and other indicators of mice in solvent group, enrofloxacin group and minocycline group were significantly different ( F=7.13-94.35, all P<0.05). Compared with enrofloxacin group, mice in minocycline group had shorter floating immobility time ((169.30±13.04) s, (224.30±22.60) s, P<0.05) and higher sugar water preference rate ((62.81±7.75) %, (47.71±8.11) %, P<0.05), the mean value of platform approach estimation after water maze correction was lower ((97.66±14.56) mm, (120.20±12.08) mm, P<0.05), and the expression level of Nissl bodies was higher ((80.17±10.55) cells /mm 2, (52.00±8.94) cells /mm 2, P<0.05), NeuN expression rate was high ((45.04±3.62) %, (28.88±4.50) %, P<0.05), Iba-1 expression was lower ((97.33±10.67) cells/mm 2, (112.50±6.54)cells/mm 2, P<0.05), the percent of M1 microglia expression was lower ((54.43±5.22) %, (73.82±6.88) %, P<0.05), and the percent of M2 microglia expression was significantly higher ((51.86±6.22) %, (36.30±5.72) %, P<0.05). The expression levels of IL-6 ((0.75±0.06), (1.21±0.07), P<0.05) and IL-1β ((0.61±0.06) (1.09±0.09), P<0.05) were lower. Conclusion:The long-term spatial memory impairment of post-stroke depression mice is aggravated, which is related to the neuron damage caused by increased activation of M1 microglia in PFC area.Inhibition of M1 microglia by minocycline can effectively improve the spatial memory ability of mice.

Cognitive training using the abacus: a literature review study on the benefits for different age groups / Treino cognitivo com o uso do ábaco: um estudo de revisão da literatura sobre os benefícios para os diferentes grupos etários

ABSTRACT. The literature indicates that cognitive stimulation interventions have shown promising results. Abacus represents a tool with great potential in such interventions. Objectives: To carry out a systematic review of studies published in recent years that entailed the delivery of a cognitive training program using an abacus to boost target cognitive abilities of older persons and also other age groups, with or without cognitive impairment. Methods: A systematic review study was conducted in July 2020 involving PubMed, MedLine, LILACS, and SciELO databases. Results: A total of 29 studies were retrieved, of which 8 aimed to identify the effect of abacus-based mental calculation (AMC) for different age groups and to determine its applicability as a method of cognitive stimulation for older adults. In AMC technique, participants first learn to use the physical abacus (PA) and after achieving proficiency they perform calculations using a mental image of the device, manipulating the beads of the so-called mental abacus (MA). Conclusions: The number of studies addressing abacus use as a cognitive training tool was rather limited, considering the relevance of the theme. Their interventions have shown benefits for cognitive functioning of individuals of various age groups, including older adults with cognitive impairment. Future studies that involve larger samples of healthy and/or cognitively impaired older adults with a longitudinal design and a more elaborate methodological design are suggested.

RESUMO. A literatura aponta que intervenções de estimulação cognitiva têm mostrado resultados promissores. O ábaco representa uma ferramenta com grande potencial nesse tipo de intervenções. Objetivo: Realizar uma revisão sistemática de estudos publicados nos últimos anos que buscaram, em seus métodos, oferecer um programa de treino cognitivo com o uso do ábaco para estimular habilidades-alvo em idosos e em pessoas de outras faixas etárias, com ou sem comprometimento cognitivo. Métodos: Estudo de revisão sistemática, realizado em julho de 2020, utilizando-se as bases de dados PubMed, MedLine, LILACS e SciELO. Resultados: Um total de 29 estudos foram encontrados, dos quais oito objetivaram identificar o efeito do treino de uma técnica chamada abacus-based mental calculation (AMC) em diferentes faixas etárias e verificar sua aplicabilidade como método de estimulação cognitiva para idosos. No AMC, os participantes aprendem inicialmente a manipular o ábaco físico (PA, na sigla em inglês) e, após adquirirem agilidade, passam a realizar cálculos com uma imagem mental do instrumento, manipulando as contas do denominado ábaco mental (MA, na sigla em inglês). Conclusões: O número de estudos que abordaram o uso do ábaco como ferramenta para realização de treino cognitivo foi bastante limitado diante da relevância do tema. Os estudos analisados apresentaram benefícios do treino cognitivo com uso do ábaco para o desempenho cognitivo de indivíduos de diversas faixas etárias, inclusive em idosos com comprometimento cognitivo. Para estudos futuros, espera-se a realização de mais pesquisas com amostras maiores, com delineamento longitudinal e com métodos bem elaborados, com enfoque em pessoas idosas, saudáveis e/ou com comprometimento cognitivo.

Optogenetic study of glutamatergic neuron in parasubiculum in visuospatial memory / 中华行为医学与脑科学杂志

Objective:To investigate the function of glutamatergic neuron of the parasubiculum in spatial memory.Methods:Sixteen adult male C57BL/6 mice aged 6-8 weeks were divided into two groups randomly, 0.4 μl AAV5-CaMKⅡα-eNpHR3.0-eYFP was injected into the bilateral parasubiculum respectively in experimental group, equal dose AAV5-CaMKⅡα-eYFP for control group.The optic fiber was implanted 6 weeks after virus injection.The novel object place recognition test was performed one week after optic fiber implantation, continuous yellow light was delivered during the behavioral test to inhibit the function of glutamatergic neuron in the parasubiculum.The standard memory index (D2) was used to evaluate the spatial memory function.SPSS 20.0 software was used to process the data, and the independent-samples t-test and paired-samples t-test were used for data analysis. Results:In the novel object place recognition experiment, the mice showed no preference for either object in both control group(new object: 0.51±0.06, familiar object: 0.49±0.04, t=1.21, P>0.05) and experimental group(new object: 0.49±0.05, familiar object: 0.50±0.04, t=-0.78, P>0.05). Compared with the control group (0.55±0.06), the D2 score of the experimental group (0.26±0.07) was significantly lower ( t=-2.96, P<0.05), and the number of c-fos positive neuron in experimental group (96.33±7.13) was also significantly less than that in control group (127.67±5.24, t=-3.54, P<0.05). Conclusion:Inhibiting glutamatergic neuronal activity in the parasubiculum impairs spatial memory in mice, suggesting that glutamatergic neurons of the parasubiculum play an important role in spatial memory.

Auraptene has neuroprotective and memory enhancing effects in a rat model of Alzheimer’s disease

@#Background: Auraptene is a simple coumarin that exhibits multiple protective activities in the brain. Alzheimer’s disease is a complex, multifactorial, and progressive neurodegenerative disease. Microinjection of the β-amyloid peptide (Aβ) into the hippocampus of rat has been recognized as a reliable and stable animal model of Alzheimer’s disease, which mimics the memory deficits. In the present study, the memory enhancing effects of auraptene were studied in rats that Aβ was injected into their hippocampus to create a model of Alzheimer’s disease. Methods: Different doses of auraptene (5, 10 and 25 mg/kg) were administered intraperitoneally to male Wistar rats. The spatial memory performance was tested by Morris water maze after Alzheimer`s induction. The hippocampal expression of pro-apoptotic Bax and anti-apoptotic Bcl-2 proteins were calculated for evaluating the neuroprotective and anti-apoptotic effects of Auraptene in the brain tissue. Results: In comparison with the control group, auraptene significantly decreased the escape latency time in the treated rats. In addition, auraptene increased the percentage of time spent and traveled pathway in the target quadrant. Molecular data showed that auraptene attenuated the Bax/Bcl-2 ratio in the hippocampus of rats. Conclusion: This study demonstrated the memory enhancing effect of Aur after Aβ injection, which could be through inhibiting the apoptotic pathways in the hippocampus of rats.

Egocentric and allocentric spatial memory in healthy aging: performance on real-world tasks

Although normal aging has been related to several cognitive difficulties, other processes have been studied less, such as spatial memory. Our aim was to compare egocentric and allocentric memory in an elderly population using ecological tasks. Twenty-eight cognitively unimpaired participants performed Egocentric and Allocentric Spatial Memory Tasks, as well as Spatial Span from CANTAB, Benton's Judge of Line Orientation test (JoLO), and Montreal Cognitive Assessment test (MoCA). The results revealed that younger participants showed better performance than older participants on both the Egocentric and Allocentric Spatial Memory Tasks, although only the Egocentric test was able to discriminate between younger, middle, and older elderly participants. Learning effect was found in Allocentric Spatial Memory Task in younger and older groups, but not in the middle group. Allocentric and egocentric performance was not related to other visuospatial neuropsychological scores and gender did not influence performance in any task. Egocentric and Allocentric Spatial Memory Tasks may be useful tools in early screening for cognitive decline, as they are able to detect age differences in the cognitive unimpaired elderly population.

Valproic acid withdrawal ameliorates impairments of hippocampal-spatial working memory and neurogenesis / 浙江大学学报（英文版）（B辑：生物医学和生物技术）

Valproic acid (VPA), an agent that is used to treat epileptic seizures, can cause spatial memory impairment in adults and children. This effect is thought to be due to the ability of VPA to inhibit neurogenesis in the hippocampus, which is required for learning. We have previously used an animal model to show that VPA significantly impairs hippocampal-spatial working memory and inhibits neuronal generation in the sub-granular zone of the dentate gyrus. As there are patient reports of improvements in memory after discontinuing VPA treatment, the present study investigated the recovery of both spatial memory and hippocampal neurogenesis at two time points after withdrawal of VPA. Male Wistar rats were given intraperitoneal injections of 0.9% normal saline or VPA (300 mg/kg) twice a day for 10 d. At 1, 30, or 45 d after the drug treatment, the novel object location (NOL) test was used to examine spatial memory; hippocampal cell division was counted using Ki67 immunohistochemistry, and levels of brain-derived neurotrophic factor (BDNF) and Notch1 were measured using western immunoblotting. Spatial working memory was impaired 1 and 30 d after the final administration, but was restored to control levels by 45 d. Cell proliferation had increased to control levels at 30 and 45 d. Both markers of neurogenesis (BDNF and Notch1 levels) had returned to control levels at 45 d. These results demonstrate that memory recovery occurs over a period of six weeks after discontinuing VPA treatment and is preceded by a return of hippocampal neurogenesis to control levels.

Construction of stomatology students spatial memory based on staged mindmapping in the dental anatomy course / 解剖学报

Objective: To discusse the application effect of mindmapping on the construction of stomatology students' spatial memory on dental anatomy by integrating into a system's internal knowledge framework based on staged mindmapping. Methods: This study was performed among 121 Grade 2016 students majoring in oral medicine in our school. The dental anatomy chapter of the course of oral anatomy and physiology was selected, and Mindjet MindManager 2019 software was used to make a staged mind map of dental anatomy. The mindmapping experimental group (60 students) was divided into three stages during the teaching process: preview before class stage (focus on the summary of key knowledge points), theory teaching stage (focus on the detailing of knowledge points), and review after class stage (focus on the linking of knowledge points). The conventional teaching group (61 students) adopted method conventionally used in lectures. After the lecture, students scores in theoretical written and practical training examinations were compared and analyzed between the two groups, and the clinical memory scale was used to test the memory ability of the two groups of students. Results: The total scores and subjective question scores of the mindmapping experimental group in the theoretical examination were better than the conventional teaching group (P0.05). According to the testing items of the clinical memory scale, after implementing the staged mindmapping teaching method in the two groups, students scores in the free memory of images, the recognition of meaningless figures and the portrait-feature associated recall were compared between the two groups. The scores of the mindmapping experimental group were all significantly higher than the conventional teaching group (P 0.05) in directed memory scores and associative learning scores. Conclusion: Compared with conventional teaching method, staged mindmapping plays a role in strengthening logical memory in students' spatial thinking construction, which can help students explore the relevance among knowledge points and construct a relatively complete knowledge system.

Effects of different doses of methamphetamine on spatial learning and memory in mice and the mechanism / 西安交通大学学报(医学版)

Objective: To investigate the different-dose effects of methamphetamine (METH) on spatial learning and memory and the possible mechanisms. Methods: C57BL/6 mice were treated with 0.5, 1.0 and 2.0 mg/kg of METH or normal saline. The drug was injected intraperitoneally 30 min prior to the Morris water maze. All mice experienced 5 consecutive days' positioning navigation experiment and the spatial exploration experiment conducted 24 hours after the last training trial. Immediately after the probe test, the mice were killed by cervical dislocation and the hippocampus was dissected. Western blot was used to detect changes in phosphorylation levels of extracellular signal-regulated kinase (ERK1/2) and cAMP response element-binding protein (CREB) in the hippocampus. Results: Compared with the mice in saline group, those in 1.0 mg/kg METH group had a significantly shorter latency (P<0.05), spent more time in the target quadrant (P<0.05), and had more platform site crossings (P<0.05). Moreover, 0.5 and 2.0 mg/kg of METH did not significantly affect the mice's spatial learning and memory, but 0.5 mg/kg of METH showed a memory-promoting trend, while 2.0 mg/kg of METH showed a memory-destroying trend. METH of 1.0 mg/kg significantly increased p-ERK1/2 (P<0.05) and p-CREB (P<0.05) levels in the hippocampus. Conclusion: METH of 1.0 mg/kg significantly improved mice's spatial learning and memory. The effect of METH is an inverted U-curve among three doses of METH at 0.5, 1.0 and 2.0 mg/kg. ERK1/2 and CREB in the hippocampus may be involved in METH-induced improvement of spatial learning and memory in mice.

The Glutamatergic Postrhinal Cortex-Ventrolateral Orbitofrontal Cortex Pathway Regulates Spatial Memory Retrieval / 神经科学通报·英文版

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 spatial memory 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.

Mnemonic and Histopathological Assessment of the Neuroprotective Effects of Murraya Koenigii Leaves Extract in Rats with Partial Global Cerebral Ischaemia

@#Introduction: Preclinical studies have reported that Murraya koenigii leaves (MKL) could enhance memory. MKL is also known for its antioxidant activity. The current study was to assess the possible neuroprotective potential of MKL methanolic extract in a two vessel occlusion (2VO) rat model of partial global cerebral ischaemia. Methods: Rats were divided into memory and learning groups. Each group was subdivided into sham control, untreated 2VO and MKL-treated 2VO subgroups. The Morris water maze test was implemented to assess the rats’ cognitive function postoperatively. Brain samples were histopathologically examined for viable neurons within the CA1 hippocampal region. Results: Water maze test findings showed that MKL positively improved memory and learning impairments. However, this improvement in memory test for the treated group was still significantly inferior to that of the healthy control group. Additionally, MKL treated group exhibited insignificant difference in the number of viable hippocampal CA1 pyramidal neurons from that of the untreated 2VO group, whereas both MKL treated and untreated 2VO groups showed significantly less viable neurons when compared with the control group. Conclusion: MKL extract modestly improved memory without providing substantial neuroprotective action to the hippocampal neurons in rats with chronic partial global cerebral ischaemia.

Expression of synaptophysin in hippocampal CA1 region and prefrontal cortex of PTSD rats / 中国病理生理杂志

AIM:To investigate the expression of synaptophysin in the CA1 region of hippocampus and prefrontal cortex (PFC) of rats with posttraumatic stress disorder (PTSD) , and to explore the mechanism of spatial memory changes in PTSD rats.METHODS:Healthy adult SD rats (n=36) were randomly divided into 2 groups:control group and model group, with 18 rats in each group.The rats in model group was continuously given single prolonged stress (SPS) to construct the PTSD model.Morris water maze (MWM) was used to test the learning and memory ability of the rats in the2 groups.The protein expression of synaptophysin in the hippocampal CA1 area and PFC was examined by immunohistochemistry, Western blot and immunofluorescence experiments.RESULTS:The latency of the rats in searching for the underwater platform in model group was significantly longer than that in control group from the 2nd day (P<0.01) in the MWM experiment, the target quadrant swimming time was significantly shortened (P<0.01) , and the times of crossing the platform were also significantly reduced (P<0.01).The results of immunohistochemistry, Western blot and immunofluorescence experiments showed that the expression of synaptophysin was obviously reduced in the CA1 region of hippocampus and PFC in model group as compared with control group (P<0.05 or P<0.01).CONCLUSION:The reduction of spatial memory ability in PTSD rats may be associated with the decreased expression of synaptophysin in the CA1 region of hippocampus and PFC.