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1.
Acta Physiologica Sinica ; (6): 777-784, 2020.
Article in Chinese | WPRIM | ID: wpr-878225

ABSTRACT

The objective of this study was to elucidate the effect of chronic stress (CS) on dopamine (DA) level and synaptic efficiency in the hippocampal dentate gyrus (DG) during spatial learning and memory. Sprague Dawley (SD) male rats were randomly divided into control group and CS group (n = 10). CS group was treated with chronic mild unpredictable stress, and control group did not receive any treatments. The levels of epinephrine and corticosterone (CORT) in serum were measured by using enzyme-linked immunosorbent assay (ELISA); the spatial learning and memory abilities of rats were measured by Morris water maze (MWM) test. Meanwhile, the amplitude of field excitatory postsynaptic potential (fEPSP) and concentration of DA in the DG region were determined by in vivo electrophysiology, microdialysis and HPLC techniques during MWM test in rats. After that, the DA D1 receptor (D1R) and its key downstream members in DG were examined by immunohistochemistry or Western blot assay. The results showed that the levels of epinephrine and CORT in the serum of the rats in CS group were significantly increased compared with those in the control group (P < 0.05). In CS group rats, the escape latency was significantly prolonged and the number of platform crossing was markedly decreased during MWM test, compared with those in control group (P < 0.05). Furthermore, the amplitude of fEPSP in the DG was not changed during MWM test in CS rats, while it was significantly increased on the 3rd day of MWM test in control group (P < 0.05). Compared with baseline or control group, CS group showed significantly increased DA level from the 1st to 3rd days of MWM test in the DG (P < 0.05). In addition, the protein expression of D1R was markedly up-regulated in the DG in CS group, while the protein expression levels of p-PKA, p-CREB and BDNF were significantly reduced, compared with those in control group. These results suggest that CS may impair spatial learning and memory abilities in rats through the enhancement of the DA levels in the hippocampal DG.


Subject(s)
Animals , Dentate Gyrus , Dopamine , Hippocampus , Male , Maze Learning , Rats , Rats, Sprague-Dawley , Spatial Learning , Spatial Memory
2.
Article in English | WPRIM | ID: wpr-787140

ABSTRACT

Alzheimer's disease (AD) is the most common neurodegenerative disorder causing dementia worldwide, and is mainly characterized by aggregated β-amyloid (Aβ). Increasing evidence has shown that plant extracts have the potential to delay AD development. The plant sterol β-Sitosterol has a potential role in inhibiting the production of platelet Aβ, suggesting that it may be useful for AD prevention. In the present study, we aimed to investigate the effect and mechanism of β-Sitosterol on deficits in learning and memory in amyloid protein precursor/presenilin 1 (APP/PS1) double transgenic mice. APP/PS1 mice were treated with β-Sitosterol for four weeks, from the age of seven months. Brain Aβ metabolism was evaluated using ELISA and Western blotting. We found that β-Sitosterol treatment can improve spatial learning and recognition memory ability, and reduce plaque load in APP/PS1 mice. β-Sitosterol treatment helped reverse dendritic spine loss in APP/PS1 mice and reversed the decreased hippocampal neuron miniature excitatory postsynaptic current frequency. Our research helps to explain and support the neuroprotective effect of β-Sitosterol, which may offer a novel pharmaceutical agent for the treatment of AD. Taken together, these findings suggest that β-Sitosterol ameliorates memory and learning impairment in APP/PS1 mice and possibly decreases Aβ deposition.


Subject(s)
Alzheimer Disease , Amyloid , Animals , Blood Platelets , Blotting, Western , Brain , Cognition Disorders , Dementia , Dendritic Spines , Enzyme-Linked Immunosorbent Assay , Excitatory Postsynaptic Potentials , Learning , Memory , Metabolism , Mice , Mice, Transgenic , Neurodegenerative Diseases , Neurons , Neuroprotective Agents , Plant Extracts , Plants , Plaque, Amyloid , Spatial Learning
3.
Braz. arch. biol. technol ; 63: e20180379, 2020. tab, graf
Article in English | LILACS | ID: biblio-1132267

ABSTRACT

Abstract Hippocampus is a part of the brain that has a major role in spatial learning and memory which can be affected by herbal extracts. Incense resin (Styrax benzoin) has been used by local communities to improve intelligence. However, there is no scientific evidence of the functions of Styrax benzoin for regulating hippocampal function. The aim of this study was intended to analyze and investigate the effect of incense resin on learning, memory, and dendrite complexity of mice. Three months old male Deutch Democratic Yokohama (DDY) mice were injected orally with graded doses of 100, 150, and 200 mg/kg of incense resin aqueous extract daily for 30 days. Spatial learning and memory performance levels were tested with Y-maze alternation, novel object recognition, and Morris water maze. The branches and maximum dendritic span in the dentate gyrus were observed by the Golgi-Cox staining. Overall, our results showed that incense resin extract increased learning and memory ability, and the number of dendrite branching in the dentate gyrus.


Subject(s)
Animals , Male , Mice , Dendritic Cells/drug effects , Plant Extracts/pharmacology , Styrax/chemistry , Spatial Learning/drug effects , Memory/drug effects , Administration, Oral , Maze Learning/drug effects
4.
Pensam. psicol ; 17(1): 101-112, ene.-jun. 2019. tab, graf
Article in Spanish | LILACS | ID: biblio-1020105

ABSTRACT

Resumen Objetivo. Identificar y precisar las dificultades en funciones espaciales que presentan los niños con TDAH en edad escolar. Método. Se evaluaron 24 niños, entre los 6 y los 12 años de edad, con diagnóstico de TDAH. Todos los niños fueron evaluados con tareas gráficas, tareas verbales y tareas constructivas, incluidas en las pruebas Evaluación Neuropsicológica Infantil, Evaluación Neuropsicológica de la Integración Espacial y Evaluación Neuropsicológica del Éxito Escolar. Resultados. El análisis clínico realizado al desempeño de los niños mostró dificultades no solo en el manejo de la proporción, la integración y al dibujar ángulos, sino en el uso adecuado del espacio e inversión. Las dificultades espaciales estuvieron acompañadas de otras de índole regulatorio, tono de activación, motoras y cinestésicas. Los participantes con mayor número de errores fueron aquellos de menor edad. Conclusión. Los niños con diagnóstico de TDAH pueden presentar dificultades en el desarrollo de las funciones espaciales, por lo cual se hace necesario que la evaluación neuropsicológica incluya un análisis profundo de esta dimensión cognitiva, que permita indagar la naturaleza de estas dificultades y su posible relación con el desarrollo de otras funciones.


Abstract Objective. Identify and detail the difficulties in children with attention deficit disorder in spatial function tasks. Method. 24 school children between 6 and 12 years old with diagnosis of attention deficit disorder were included in the study. Neuropsychological tasks used in the study were divided in graphic tasks, verbal tasks and a constructive task, all of them included in the Neuropsychological Evaluation for Children, Neuropsychological Evaluation of the Spatial Integration and Neuropsychological Evaluation of School Success assessments. Results. Analysis of the results has pointed out specific errors in graphic tasks such as disproportion, disintegration, difficulties with angles, problems with usage of space and inversions. Younger participants with complex neuropsychological syndromes committed more mistakes. The spatial difficulties were accompanied by regulatory, activation, motor and kinesthetic difficulties. The participants with higher frequencies of error were those of lower age. Conclusion. The results show that children with attention deficit disorder diagnosis may have difficulties in the development of spatial function; therefore, it is necessary to include a more profound neuropsychological analysis of the domain that allows the investigation of the nature of the difficulties and its plausible relation to the development of other functions.


Resumo Escopo. Identificar e reconhecer as dificuldades em funções espaciais que apresentam as crianças com TDAH em idade escolar. Metodologia. Foram avaliadas 20 crianças masculinas e 4 femininas, com idades compreendidas entre os 6 e 12 anos de idade, com diagnóstico de TDAH. Todas as crianças foram avaliadas com tarefas gráficas, tarefas verbais e tarefas construtivas, incluídas nas provas Avaliação Neuropsicológica da Integração espacial e Avaliação Neuropsicológica do Sucesso Escolar. Resultados. A análise clínica realizada aos desempenhos das crianças, mostraram dificuldades de desproporção, desintegração, dificuldade para desenhar ângulos, uso inadequado do espaço e inversão. As dificuldades espaciais estiveram acompanhadas de outras de natureza regulatória, tono de ativação, motoras e cinestésicas. Os participantes com maior número de erros foram aqueles de menor idade. Conclusão. As crianças com diagnóstico de déficit de atenção podem apresentar dificuldades no desenvolvimento das funções espaciais, pelo qual é preciso que a avaliação neuropsicológica possa incluir uma análise profunda de esta dimensão cognitiva, que permita indagar a natureza de estas dificuldades e sua possível relação com o desenvolvimento de outras funções.


Subject(s)
Humans , Child , Attention Deficit Disorder with Hyperactivity , Child Development , Evaluation Studies as Topic , Spatial Learning , Neuropsychology
5.
Rev. chil. neuro-psiquiatr ; 57(2): 149-157, jun. 2019. tab, graf
Article in Spanish | LILACS | ID: biblio-1042684

ABSTRACT

Resumen Introducción: La masticación es una actividad periférica que influye positivamente sobre el sistema nervioso central (SNC). Sin embargo, a pesar de los diferentes estudios realizados, aún no está claro cómo la masticación afecta a los procesos cognitivos. Debido a ello se buscó determinar el efecto de la masticación sobre la memoria y aprendizaje espacial en ratones adultos y seniles. Materiales: Se empleó un grupo de 16 ratones adultos y de 16 ratones seniles que fueron aleatorizados en 2 subgrupos de 8 ratones cada uno. Un subgrupo se alimentó con dieta granosa convencional para ratón (subgrupo masticación normal), el otro subgrupo se alimentó con dieta en polvo (subgrupo masticación deficiente). Durante 2 meses se sometió a cada subgrupo a su dieta respectiva. Se evaluó en el laberinto acuático de Morris a los ratones adultos a los 7 meses de edad y a los seniles a los 12 meses de edad, mediante la fase de adquisición y de fase de recuperación de memoria y aprendizaje espacial. Resultados: Los ratones adultos, con masticación normal, mostraron mejor adquisición de memoria y aprendizaje espacial con respecto a los ratones con masticación deficiente en el primer día de evaluación (p = 0,035). Al agrupar a los ratones bajo el mismo tipo de masticación se encontró, en los subgrupos bajo masticación normal, una mejor adquisición de memoria y aprendizaje espacial en el subgrupo adulto sobre el subgrupo senil (p < 0,05). Conclusiones: La masticación normal tuvo un efecto positivo sobre la adquisición de información espacial en los ratones adultos.


Introduction: Chewing is a peripheral activity that positively influences the central nervous system (CNS). However, despite the different studies carried out, it is still not clear how chewing affects cognitive processes. Because of this, was trying to find the effect of chewing on memory and spatial learning in adult and senile mice. Methods: A group of 16 adult and senile mice were randomized into 2 subgroups of 8 mice each group. One subgroup was fed with conventional grainy diet for mice (normal chewing subgroup), the other subgroup was fed dietary powder (deficient chewing subgroup). During 2 months each subgroup was submitted to their respective diet. Adult mice at 7 months of age and senile at 12 months of age were evaluated in the Morris' water maze; through of the acquisition phase and the probe test of memory and spatial learning. Results: Adult mice with normal chewing showed better memory acquisition and spatial learning with respect to mice with deficient chewing on the first day of evaluation (p = 0.035). When grouping the mice in the same type of chewing, in the subgroups under normal chewing, a better acquisition of memory and spatial learning was found in the adult subgroup on than in the senile subgroup (p < 0.05). Conclusions: Normal chewing had a positive effect on the acquisition of spatial information in adult mice.


Subject(s)
Animals , Mice , Central Nervous System , Cognition , Spatial Learning , Mastication , Memory
6.
Article in English | WPRIM | ID: wpr-785606

ABSTRACT

OBJECTIVE: Sequelae of behavioral impairments associated with human traumatic brain injury (TBI) include neurobehavioral problems. We compared exploratory, cognitive, and depressive-like behaviors in pediatric and adult male mice exposed to controlled cortical impact (CCI).METHODS: Pediatric (21 to 25 days old) and adult (8 to 12 weeks old) male C57Bl/6 mice underwent CCI at a 2-mm depth of deflection. Hematoxylin and eosin staining was performed 3 to 7 days after recovery from CCI, and injury volume was analyzed using ImageJ. Neurobehavioral characterization after CCI was performed using the Barnes maze test (BMT), passive avoidance test, open-field test, light/dark test, tail suspension test, and rotarod test. Acutely and subacutely (3 and 7 days after CCI, respectively), CCI mice showed graded injury compared to sham mice for all analyzed deflection depths.RESULTS: Time-dependent differences in injury volume were noted between 3 and 7 days following 2-mm TBI in adult mice. In the BMT, 2-mm TBI adults showed spatial memory deficits compared to sham adults (P < 0.05). However, no difference in spatial learning and memory was found between sham and 2-mm CCI groups among pediatric mice. The open-field test, light/dark test, and tail suspension test did not reveal differences in anxiety-like behaviors in both age groups.CONCLUSION: Our findings revealed a graded injury response in both age groups. The BMT was an efficient cognitive test for assessing spatial/non-spatial learning following CCI in adult mice; however, spatial learning impairments in pediatric mice could not be assessed.


Subject(s)
Adult , Animals , Brain Injuries , Eosine Yellowish-(YS) , Hematoxylin , Hindlimb Suspension , Humans , Learning , Male , Memory , Mice , Rotarod Performance Test , Spatial Learning , Spatial Memory
7.
Article in English | WPRIM | ID: wpr-773418

ABSTRACT

OBJECTIVE@#To estimate the detrimental effects of shortwave exposure on rat hippocampal structure and function and explore the underlying mechanisms.@*METHODS@#One hundred Wistar rats were randomly divided into four groups (25 rats per group) and exposed to 27 MHz continuous shortwave at a power density of 5, 10, or 30 mW/cm2 for 6 min once only or underwent sham exposure for the control. The spatial learning and memory, electroencephalogram (EEG), hippocampal structure and Nissl bodies were analysed. Furthermore, the expressions of N-methyl-D-aspartate receptor (NMDAR) subunits (NR1, NR2A, and NR2B), cAMP responsive element-binding protein (CREB) and phosphorylated CREB (p-CREB) in hippocampal tissue were analysed on 1, 7, and 14 days after exposure.@*RESULTS@#The rats in the 10 and 30 mW/cm2 groups had poor learning and memory, disrupted EEG oscillations, and injured hippocampal structures, including hippocampal neurons degeneration, mitochondria cavitation and blood capillaries swelling. The Nissl body content was also reduced in the exposure groups. Moreover, the hippocampal tissue in the 30 mW/cm2 group had increased expressions of NR2A and NR2B and decreased levels of CREB and p-CREB.@*CONCLUSION@#Shortwave exposure (27 MHz, with an average power density of 10 and 30 mW/cm2) impaired rats' spatial learning and memory and caused a series of dose-dependent pathophysiological changes. Moreover, NMDAR-related CREB pathway suppression might be involved in shortwave-induced structural and functional impairments in the rat hippocampus.


Subject(s)
Animals , Cyclic AMP Response Element-Binding Protein , Genetics , Metabolism , Dose-Response Relationship, Radiation , Electroencephalography , Radiation Effects , Hippocampus , Radiation Effects , Male , Memory , Radiation Effects , Nissl Bodies , Physiology , Radiation Effects , Radio Waves , Random Allocation , Rats , Rats, Wistar , Receptors, N-Methyl-D-Aspartate , Genetics , Metabolism , Spatial Learning , Radiation Effects
8.
Experimental Neurobiology ; : 485-494, 2019.
Article in English | WPRIM | ID: wpr-763779

ABSTRACT

Vacuolar protein sorting-associated protein 13B (VPS13B), also known as COH1, is one of the VPS13 family members which is involved in transmembrane transport, Golgi integrity, and neuritogenesis. Mutations in the VPS13B gene are associated with Cohen syndrome and other cognitive disorders such as intellectual disabilities and autism spectrum disorder (ASD). However, the patho-physiology of VPS13B-associated cognitive deficits is unclear, in part, due to the lack of animal models. Here, we generated a Vps13b exon 2 deletion mutant mouse and analyzed the behavioral phenotypes. We found that Vps13b mutant mice showed reduced activity in open field test and significantly shorter latency to fall in the rotarod test, suggesting that the mutants have motor deficits. In addition, we found that Vps13b mutant mice showed deficits in spatial learning in the hidden platform version of the Morris water maze. The Vps13b mutant mice were normal in other behaviors such as anxiety-like behaviors, working memory and social behaviors. Our results suggest that Vps13b mutant mice may recapitulate key clinical symptoms in Cohen syndrome such as intellectual disability and hypotonia. Vps13b mutant mice may serve as a useful model to investigate the pathophysiology of VPS13B-associated disorders.


Subject(s)
Animals , Autism Spectrum Disorder , Cognition Disorders , Exons , Humans , Intellectual Disability , Learning Disabilities , Memory, Short-Term , Mice , Models, Animal , Muscle Hypotonia , Phenotype , Rotarod Performance Test , Social Behavior , Spatial Learning , Water
9.
Article | WPRIM | ID: wpr-763554

ABSTRACT

OBJECTIVE: Hypoxic-ischemic (HI) brain injury in the human perinatal period often leads to significant long-term neurobehavioral dysfunction in the cognitive and sensory-motor domains. Using a neonatal HI injury model (unilateral carotid ligation followed by hypoxia) in postnatal day seven rats, the present study investigated the long-term effects of HI and potential behavioral protective effect of pentoxifylline. METHODS: Seven-day-old rats underwent right carotid ligation, followed by hypoxia (FiO2 = 0.08). Rats received pentoxifylline immediately after and again 2 hours after hypoxia (two doses, 60–100 mg/kg/dose), or serum physiologic. Another set of seven-day-old rats was included to sham group exposed to surgical stress but not ligated. These rats were tested for spatial learning and memory on the simple place task in the Morris water maze from postnatal days 77 to 85. RESULTS: HI rats displayed significant tissue loss in the right hippocampus, as well as severe spatial memory deficits. Low-dose treatment with pentoxifylline resulted in significant protection against both HI-induced hippocampus tissue losses and spatial memory impairments. Beneficial effects are, however, negated if pentoxifylline is administered at high dose. CONCLUSION: These findings indicate that unilateral HI brain injury in a neonatal rodent model is associated with cognitive deficits, and that low dose pentoxifylline treatment is protective against spatial memory impairment.


Subject(s)
Animals , Hypoxia , Brain Injuries , Brain , Cognition Disorders , Hippocampus , Humans , Hypoxia-Ischemia, Brain , Learning , Ligation , Memory , Pentoxifylline , Rats , Rodentia , Spatial Learning , Spatial Memory , Water
10.
Article in English | WPRIM | ID: wpr-763534

ABSTRACT

OBJECTIVE: Although, accumulating evidence is delineating a neuroprotective and neurotrophic role for lithium (Li), inconsistent findings have also been reported in human studies especially. Moreover, the effects of Li infusion into the hippocampus are still unknown. The aims of this work were (a) to assess whether basal synaptic activity and long-term potentiation (LTP) in the hippocampus are different in regard to intrahippocampal Li infusion; (b) to assess spatial learning and memory in rats chronically treated with LiCO₃ in the Morris water maze. METHODS: Field potentials were recorded form the dentate gyrus, stimulating perforant pathways, in rats chronically (20 mg/kg for 40 days) or acutely treated with LiCO₃ and their corresponding control rats. In addition, performance of rats in a Morris water maze was measured to link behaviour of rats to electrophysiological findings. RESULTS: LiCO₃ infusion into the hippocampus resulted in enhanced LTP, especially in the late phases, but attenuated LTP was observed in rats chronically treated with Li as compared to controls. Li-treated rats equally performed a spatial learning task, but did spend less time in target quadrant than saline-treated rats in Morris water maze. CONCLUSION: Despite most data suggest that Li always yields neuroprotective effects against neuropathological conditions; we concluded that a 40-day treatment of Li disrupts hippocampal synaptic plasticity underlying memory processes, and that these effects of prolonged treatment are not associated with its direct chemical effect, but are likely to be associated with the molecular actions of Li at genetic levels, because its short-term effect preserves synaptic plasticity.


Subject(s)
Adult , Animals , Dentate Gyrus , Hippocampus , Humans , Learning , Lithium , Long-Term Potentiation , Memory , Neuronal Plasticity , Neuroprotective Agents , Perforant Pathway , Rats , Spatial Learning , Spatial Memory , Water
11.
Braz. j. med. biol. res ; 52(5): e8026, 2019. tab, graf
Article in English | LILACS | ID: biblio-1001526

ABSTRACT

Carassius auratus is a teleost fish that has been largely used in behavioral studies. However, little is known about potential environmental influences on its performance of learning and memory tasks. Here, we investigated this question in C. auratus, and searched for potential correlation between exercise and visuospatial enrichment with the total number of telencephalic glia and neurons. To that end, males and females were housed for 183 days in either an enriched (EE) or impoverished environment (IE) aquarium. EE contained toys, natural plants, and a 12-hour/day water stream for voluntary exercise, whereas the IE had none of the above. A third plus-maze aquarium was used for spatial and object recognition tests. Different visual clues in 2 of its 4 arms were used to guide fish to reach the criteria to complete the task. The test consisted of 30 sessions and was concluded when each animal performed three consecutive correct choices or seven alternated, each ten trials. Learning rates revealed significant differences between EE and IE fish. The optical fractionator was used to estimate the total number of telencephalic cells that were stained with cresyl violet. On average, the total number of cells in the subjects from EE was higher than those from subjects maintained in IE (P=0.0202). We suggest that environmental enrichment significantly influenced goldfish spatial learning and memory abilities, and this may be associated with an increase in the total number of telencephalic cells.


Subject(s)
Animals , Male , Female , Telencephalon/metabolism , Cell Proliferation/physiology , Fishes/physiology , Spatial Learning/physiology , Spatial Memory/physiology , Physical Conditioning, Animal , Behavior, Animal/physiology , Cell Count
12.
Psychiatry Investigation ; : 935-944, 2018.
Article in English | WPRIM | ID: wpr-717825

ABSTRACT

OBJECTIVE: A radial arm maze (RAM) is an essential tool for assessing spatial learning and memory. Although this tool is widely used to study deficits in spatial memory in animal models, it has several restrictions that prevent its adaptation to human research and training. Therefore, we developed a head-mounted-display RAM (HMD-RAM) program for humans and verified its validity by comparing it to the results obtained by previous RAM studies. We also compared the HMD and a flat monitor as experimental devices. METHODS: Forty participants were recruited for the current study (Study 1: 20 participants with the HMD device; Study 2: 20 participants with the flat monitor). They navigated a virtual room as a first-person viewer and used environmental landmarks to remember their spatial position and orientation. The main dependent measures were working memory error, reference memory error, detection time, travel distance, and participant’s head movements. To validate the program, participants also conducted neuropsychological assessments and self-reported measures. RESULTS: The results for HMD-RAM tasks were consistent with the results of previous research conducted on animals, and the HMD elicited a higher sense of presence, immersion, and simulator sickness than the flat monitor. According to post-experiment questions on navigation strategy, creating landmarks was important when people were discovering locations in their environment, and an HMD was beneficial for better navigation strategy. CONCLUSION: These results suggest that the HMD-RAM is valuable for estimating spatial learning and memory in humans and may be a useful tool for early diagnosis of deficits in spatial learning and memory, including amnestic mild cognitive impairment and Alzheimer’s disease.


Subject(s)
Animals , Arm , Early Diagnosis , Head Movements , Humans , Immersion , Memory , Memory, Short-Term , Cognitive Dysfunction , Models, Animal , Spatial Learning , Spatial Memory
13.
Article in Korean | WPRIM | ID: wpr-761284

ABSTRACT

OBJECTIVES: We aimed to study the role of vestibular input on spatial memory performance in mice that had undergone bilateral surgical labyrinthectomy, semicircular canal (SCC) occlusion and 4G hypergravity exposure. METHODS: Twelve to 16 weeks old ICR mice (n=30) were used for the experiment. The experimental group divided into 3 groups. One group had undergone bilateral chemical labyrinthectomy, and the other group had performed SCC occlusion surgery, and the last group was exposed to 4G hypergravity for 2 weeks. The movement of mice was recorded using camera in Y maze which had 3 radial arms (35 cm long, 7 cm high, 10 cm wide). We counted the number of visiting arms and analyzed the information of arm selection using program we developed before and after procedure. RESULTS: The bilateral labyrinthectomy group which semicircular canal and otolithic function was impaired showed low behavioral performance and spacial memory. The semicircular canal occlusion with CO₂ laser group which only semicircular canal function was impaired showed no difference in performance activity and spatial memory. However the hypergravity exposure group in which only otolithic function impaired showed spatial memory function was affected but the behavioral performance was spared. The impairment of spatial memory recovered after a few days after exposure in hypergravity group. CONCLUSIONS: This spatial memory function was affected by bilateral vestibular loss. Space-related information processing seems to be determined by otolithic organ information rather than semicircular canals. Due to otolithic function impairment, spatial learning was impaired after exposure to gravity changes in animals and this impaired performance was compensated after normal gravity exposure.


Subject(s)
Animals , Arm , Electronic Data Processing , Gravitation , Hypergravity , Memory , Mice , Mice, Inbred ICR , Otolithic Membrane , Semicircular Canals , Spatial Learning , Spatial Memory
14.
Braz. j. med. biol. res ; 51(3): e6568, 2018. tab, graf
Article in English | LILACS | ID: biblio-889051

ABSTRACT

The goal of this study was to compare the visual contrast sensitivity (CS) of men and women exposed and not exposed to organic solvents. Forty-six volunteers of both genders aged between 18 and 41 years (mean±SD=27.72±6.28) participated. Gas station attendants were exposed to gas containing 46.30 ppm of solvents at a temperature of 304±274.39 K, humidity of 62.25±7.59% and ventilation of 0.69±0.46 m/s (a passive gas chromatography-based sampling method was used considering the microclimate variables). Visual CS was measured via the psychophysical method of two-alternative forced choice using vertical sinusoidal gratings with spatial frequencies of 0.2, 0.5, 1.0, 2.0, 5.0, 10.0, and 16.0 cpd (cycles per degree) and an average luminance of 34.4 cd/m2. The results showed that visual CS was significantly lower (P<0.05) in the following groups: i) exposed men compared to unexposed men at frequencies of 0.2, 0.5, 1.0, and 2.0 cpd; ii) exposed women compared to unexposed women at a frequency of 5.0 cpd; and iii) exposed women compared to exposed men at a frequency of 0.5 cpd, even at exposures below the tolerance limit (300 ppm). These results suggest that the visual CS of exposed men was impaired over a wider range of spatial frequencies than that of exposed women. This difference may have been due to the higher body fat content of women compared to that of men, suggesting that body fat in women can serve as a protective factor against neurotoxic effects.


Subject(s)
Humans , Male , Female , Adult , Young Adult , Contrast Sensitivity/drug effects , Occupational Exposure/adverse effects , Solvents/adverse effects , Visual Perception/physiology , Adipose Tissue/anatomy & histology , Brazil/epidemiology , Educational Status , Microclimate , Occupational Exposure/statistics & numerical data , Sensory Thresholds/physiology , Sex Factors , Spatial Learning/physiology
15.
Article in English | WPRIM | ID: wpr-728754

ABSTRACT

Anesthetics are used extensively in surgeries and related procedures to prevent pain. However, there is some concern regarding neuronal degeneration and cognitive deficits arising from regular anesthetic exposure. Recent studies have indicated that brain-derived neurotrophic factor (BDNF) and cyclic AMP response element-binding protein (CREB) are involved in learning and memory processes. Genistein, a plant-derived isoflavone, has been shown to exhibit neuroprotective effects. The present study was performed to examine the protective effect of genistein against isoflurane-induced neurotoxicity in rats. Neonatal rats were exposed to isoflurane (0.75%, 6 hours) on postnatal day 7 (P7). Separate groups of rat pups were orally administered genistein at doses of 20, 40, or 80 mg/kg body weight from P3 to P15 and then exposed to isoflurane anesthesia on P7. Neuronal apoptosis was detected by TUNEL assay and FluoroJade B staining following isoflurane exposure. Genistein significantly reduced apoptosis in the hippocampus, reduced the expression of proapoptotic factors (Bad, Bax, and cleaved caspase-3), and increased the expression of Bcl-2 and Bcl-xL. RT-PCR analysis revealed enhanced BDNF and TrkB mRNA levels. Genistein effectively upregulated cAMP levels and phosphorylation of CREB and TrkB, leading to activation of cAMP/CREB-BDNF-TrkB signaling. PI3K/Akt signaling was also significantly activated. Genistein administration improved general behavior and enhanced learning and memory in the rats. These observations suggest that genistein exerts neuroprotective effects by suppressing isoflurane-induced neuronal apoptosis and by activating cAMP/CREB-BDNF-TrkB-PI3/Akt signaling.


Subject(s)
Anesthesia , Anesthetics , Animals , Apoptosis , Body Weight , Brain-Derived Neurotrophic Factor , Cognition Disorders , Cyclic AMP Response Element-Binding Protein , Genistein , Hippocampus , In Situ Nick-End Labeling , Isoflurane , Learning , Memory , Neurons , Neuroprotective Agents , Phosphatidylinositol 3-Kinase , Phosphorylation , Rats , RNA, Messenger , Spatial Learning
16.
Article in English | WPRIM | ID: wpr-119362

ABSTRACT

BACKGROUND AND PURPOSE: Lacosamide (LCM) is an antiepileptic drug that enhances the slow inactivation of sodium channels and modulates collapsin response mediator protein-2. LCM was recently demonstrated to exert a neuroprotective effect in a murine model of traumatic brain injury and status epilepticus. Assuming the same underlying excitotoxicity-related brain injury mechanism, we hypothesized that LCM would have a neuroprotective effect in hypoxic-ischemic brain injury. METHODS: We divided rats into three groups at each testing session: pre- or postfed with LCM, fed with normal saline, and sham. A hypoxic-ischemic brain injury was induced by subjecting 7-day-old rats to right carotid artery coagulation followed by 2.5 h of exposure to 8% oxygen. The animals were killed on postnatal day 12 to evaluate the severity of brain damage. Open field testing was also performed between week 2 and week 6, and the Morris water maze test was performed in week 7 after hypoxia-ischemia. RESULTS: The incidence of liquefactive cerebral infarction was lower in rats prefed with LCM at 100 mg/kg/dose, with the mortality rate being higher at higher doses (200 and 300 mg/kg/dose). The infarct areas were smaller in LCM-prefed rats in several brain regions including the hemisphere, hippocampus, cortex, and striatum. Spatial learning and memory function were better in LCM-prefed rats (p<0.05). No effect was observed in postfed rats. CONCLUSIONS: This study suggests that LCM pretreatment exerts a neuroprotective effect on hypoxia-ischemia in neonatal rats. The obtained results suggest that LCM pretreatment could be used as an effective neuroprotective method for neonates under hypoxic-ischemic conditions including heart surgery.


Subject(s)
Animals , Brain Injuries , Brain , Carotid Arteries , Cerebral Infarction , Hippocampus , Humans , Incidence , Infant, Newborn , Memory , Methods , Mortality , Neuroprotection , Neuroprotective Agents , Oxygen , Rats , Semaphorin-3A , Sodium Channels , Spatial Learning , Status Epilepticus , Thoracic Surgery , Water
17.
Article in English | WPRIM | ID: wpr-69938

ABSTRACT

BACKGROUND AND PURPOSE: This study was performed to newly develop the Way-Finding Ability Scale (WFAS) for middle-aged and older adults and validate its clinical utility. METHODS: The participants for verifying construct validity included 324 adults aged from 45 to 79 years, and 22 normal old adults without way-finding deficit (WFD), 41 amnestic mild cognitive impairment (aMCI), and 35 patients with Parkinson's disease (PD-MCI) for verifying discriminant validity. All participants were administered the newly constructed 28-item WFAS. RESULTS: Exploratory factor analysis of the WFAS revealed a four-factor solution (sense of direction and inattention, spatial learning and memory, strategic ability, and cardinal direction). This four-factor structure was confirmed by confirmatory factor analysis. The discriminant validity was examined by administering the WFAS to normal older adults and two patient groups (aMCI & PD-MCI). The results showed that the total scores of two patient groups were lower than that of normal older adults. The patients with WFD had significantly lower total scores than those without WFD. Interestingly, the total scores of patients without WFD were significantly lower than those of normal older adults suggesting that the cognitive functions associated with way-finding ability (WFA) were partially impaired in aMCI and PD-MCI patients without apparent WFD. The patients with WFD had consistently lower scores in every four-factor than those without WFD. CONCLUSIONS: These results indicated that the WFAS assesses the WFD reliably as well as estimates the degree of decline in WFA.


Subject(s)
Adult , Cognition , Humans , Memory , Cognitive Dysfunction , Parkinson Disease , Spatial Learning
18.
Article in Chinese | WPRIM | ID: wpr-254951

ABSTRACT

<p><b>OBJECTIVE</b>To study the effect of nano-SiO2 on spatial learning and memory.</p><p><b>METHODS</b>Twenty-four male rats were randomly divided into 3 groups: control group (C group), low dose group (L group) and high dose group (H group). The rats were intragastrically administrated with nanometer particles at 25 and 100 mg/kg body weight every day for 4 weeks. After exposure, the ability of learning and memory of rats was tested by Morris water maze, and electrophysiological brain stereotactic method was used to test long-tear potentiation (LTP) in dentate gyrus (DG) of the rats.</p><p><b>RESULTS</b>The increase rate of body weight in H group was reduced significantly compared with C group ( P < 0.05). In the space exploration experiment of Morris water maze test, the escape latency of H group was longer than that of C group (P < 0.05). The rats of H group spent less time in finding the target quadrant (P < 0.05) . The rate of LP induction of H group was significantly lower than that of C group (P < 0.05). After high fre quency stimulation (HFS), The changes of amplitude of population spike (PS) of L group and H group were lower than those of C group significantly (P < 0.05, P < 0.01).</p><p><b>CONCLUSION</b>Nano-SiO₂may result in impairment of spatial learning and memory ability by reducing the rate of LTP induction and the increase of PS in hippocampus.</p>


Subject(s)
Animals , Dentate Gyrus , Long-Term Potentiation , Male , Maze Learning , Memory , Nanoparticles , Rats , Silicon Dioxide , Spatial Learning
19.
Article in English | WPRIM | ID: wpr-134027

ABSTRACT

PURPOSE: Exercise enhances memory function by increasing neurogenesis in the hippocampus, and circadian rhythms modulate synaptic plasticity in the hippocampus. The circadian rhythm-dependent effects of treadmill exercise on memory function in relation with neurogenesis were investigated using mice. METHODS: The step-down avoidance test was used to evaluate short-term memory, the 8-arm maze test was used to test spatial learning ability, and 5-bromo-2’-deoxyuridine immunofluorescence was used to assess neurogenesis. Western blotting was also performed to assess levels of synaptic plasticity-associated proteins, such as brain-derived neurotrophic factor, tyrosine kinase receptor B, phosphorylated cAMP response element-binding protein, early growth response protein 1, postsynaptic density protein 95, and growth-associated protein 43. The mice in the treadmill exercise at zeitgeber 1 group started exercising 1 hour after sunrise, the mice in the treadmill exercise at zeitgeber 6 group started exercising 6 hours after sunrise, and the mice in the treadmill exercise at zeitgeber 13 group started exercising 1 hour after sunset. The mice in the exercise groups were forced to run on a motorized treadmill for 30 minutes once a day for 7 weeks. RESULTS: Treadmill exercise improved short-term memory and spatial learning ability, and increased hippocampal neurogenesis and the expression of synaptic plasticity-associated proteins. These effects of treadmill exercise were stronger in mice that exercised during the day or in the evening than in mice that exercised at dawn. CONCLUSIONS: Treadmill exercise improved memory function by increasing neurogenesis and the expression of synaptic plasticity-associated proteins. These results suggest that the memory-enhancing effect of treadmill exercise may depend on circadian rhythm changes.


Subject(s)
Animals , Blotting, Western , Brain-Derived Neurotrophic Factor , Circadian Rhythm , Cyclic AMP Response Element-Binding Protein , Early Growth Response Protein 1 , Exercise Test , Fluorescent Antibody Technique , GAP-43 Protein , Hippocampus , Learning , Memory , Memory, Short-Term , Mice , Neurogenesis , Neuronal Plasticity , Post-Synaptic Density , Protein-Tyrosine Kinases , Spatial Learning
20.
Article in English | WPRIM | ID: wpr-134026

ABSTRACT

PURPOSE: Exercise enhances memory function by increasing neurogenesis in the hippocampus, and circadian rhythms modulate synaptic plasticity in the hippocampus. The circadian rhythm-dependent effects of treadmill exercise on memory function in relation with neurogenesis were investigated using mice. METHODS: The step-down avoidance test was used to evaluate short-term memory, the 8-arm maze test was used to test spatial learning ability, and 5-bromo-2’-deoxyuridine immunofluorescence was used to assess neurogenesis. Western blotting was also performed to assess levels of synaptic plasticity-associated proteins, such as brain-derived neurotrophic factor, tyrosine kinase receptor B, phosphorylated cAMP response element-binding protein, early growth response protein 1, postsynaptic density protein 95, and growth-associated protein 43. The mice in the treadmill exercise at zeitgeber 1 group started exercising 1 hour after sunrise, the mice in the treadmill exercise at zeitgeber 6 group started exercising 6 hours after sunrise, and the mice in the treadmill exercise at zeitgeber 13 group started exercising 1 hour after sunset. The mice in the exercise groups were forced to run on a motorized treadmill for 30 minutes once a day for 7 weeks. RESULTS: Treadmill exercise improved short-term memory and spatial learning ability, and increased hippocampal neurogenesis and the expression of synaptic plasticity-associated proteins. These effects of treadmill exercise were stronger in mice that exercised during the day or in the evening than in mice that exercised at dawn. CONCLUSIONS: Treadmill exercise improved memory function by increasing neurogenesis and the expression of synaptic plasticity-associated proteins. These results suggest that the memory-enhancing effect of treadmill exercise may depend on circadian rhythm changes.


Subject(s)
Animals , Blotting, Western , Brain-Derived Neurotrophic Factor , Circadian Rhythm , Cyclic AMP Response Element-Binding Protein , Early Growth Response Protein 1 , Exercise Test , Fluorescent Antibody Technique , GAP-43 Protein , Hippocampus , Learning , Memory , Memory, Short-Term , Mice , Neurogenesis , Neuronal Plasticity , Post-Synaptic Density , Protein-Tyrosine Kinases , Spatial Learning
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