Morris Water Maze Learning in Two Rat Strains Increases the Expression of the Polysialylated Form of the Neural Cell Adhesion Molecule in the Dentate Gyrus But Has No Effect on Hippocampal Neurogenesis

In the current study, the authors investigated whether Morris water maze learning induces alterations in hippocampal neurogenesis or neural cell adhesion molecule (NCAM) polysialylation in the dentate gyrus. Two frequently used rat strains, Wistar and Sprague–Dawley, were trained in the spatial or the nonspatial version of the water maze. Both training paradigms did not have an effect on survival of newly formed cells that were labeled 7–9 days prior to the training or on progenitor proliferation in the subgranular zone. However, the granule cell layer of the spatially trained rats contained significantly more positive cells of the polysialylated form of the NCAM. These data demonstrate that Morris water maze learning causes plastic change in the dentate gyrus without affecting hippocampal neurogenesis.

Effect of metformin on the spatial memory in aged rats

Background: Aging process is often accompanied with some degree of decline in all the abilities, including learning and memory. One of the attracting research fields has been devoted to finding antiaging drugs. Metformin has shown some memory-enhancing features in aged humans and laboratory animals. Aims and Objective: To evaluate the effects of 50, 75, and 100 mg/kg of metformin on the spatial memory performance of aged rats in the Morris water maze. Materials and Methods: Thirty-two male 24-month-old rats were divided randomly into four groups (n = 8) including control group and 50-, 75-, and 100-mg/kg metformin groups. After 36 days of treatment, the learning process was assessed by the reference memory task in the Morris water maze. All the rats received water maze training (four trials/day for 5 days) to assess the hippocampal-dependent spatial learning and, then, received a 60-s probe trial test of spatial memory retention 24 h after the twentieth trial. Result: Over 5 days of training, metformin (50, 75, and 100 mg/kg/day) treatment significantly reduced the latency and path length to find the escape platform (P < 0.01). In probe trials (without platform), on the last day of training, the metformin-treated groups spent significantly longer time in the platform quadrant when compared with the control group. Among the treated groups, 100 mg/kg dosage of metformin induced the best rehearsals memory (P < 0.05). Conclusion: These results showed that, in the old rats, 36-day orally administered metformin showed a positive influence on the spatial memory performance in the Morris water maze. © 2015 Farzaneh Ganji

Weak if any effect of estrogen on spatial memory in rats

In a number of species, males appear to have spatial abilities that are superior to those of females. The favored explanation for this cognitive difference is hormonal: higher testosterone levels in males than in females. An alternative explanation focuses on the role of varying levels of estrogens in females during the estrus cycle; females perform as well as males on days of low estrogen, but more poorly on days of high estrogen. Other investigators have reported that estrogens improve both types of memory processes, which depend on the striatal (nonspatial navigation) and hippocampal (spatial) memory systems. Additionally, estrogens have been found to protect the working memory. These contradictory results initiated the present study, in which ovariectomized female rats were trained to escape in a Morris water maze. The daily trials were preceded by estradiol application in low doses (Experiment I) or in higher doses (Experiment II). In Experiment I, no differences at all were found between the latencies of the treated and control groups to reach a submerged platform in a Morris water maze. In Experiment II, however, the animals treated with the higher dose of estradiol showed a small deficit in the acquisition of the Morris water maze task. This study indicates that estradiol at around the physiological level has no effect on spatial learning and memory functions

Optimization of a Novel Barnes Maze Protocol for Assessing Antioxidant Treatment Of Traumatic Brain Injury

Current preclinical research into traumatic brain injury focuses heavily upon cellular and molecular testing to determine the effects of injury and potential benefits of neuroprotective treatments. While this may be a useful method, some argue that an increased focus on behavioral testing could lead to better clinical translation as these assays assess the longer term, downstream effects from a brain injury. The most characterized behavioral tests used in traumatic brain injury research are the spatial learning and memory paradigms, Morris Water Maze and Barnes Maze. The Morris Water Maze is the most used of theses paradigms and relies on spatial cues and a platform for the escape from the water to measure spatial learning and memory but has a downside in the endogenous anxiety because of the necessity of swimming. Additionally, previous work with the Morris Water Maze showed issues in finding large differences between injured and uninjured mice. The Barnes Maze offers an alternative to the Morris Water Maze without the added stress caused by forced swimming by instead relying on bright lights to encourage rodents into the dark escape area. Here, a novel shortened Barnes Maze protocol has been developed and optimized to improve upon a traditional Barnes Maze protocol in detecting differences between healthy and injured rodents. Additionally, this protocol is used to assess the efficacy of a novel antioxidant nanoparticle treatment. Through this testing, additional knowledge regarding the ability and limitations of this experimental procedure are found as well as further knowledge into the benefits shown by a neuroprotective treatment. Advisor: Forrest Kievi

Morris Water Maze Experiment

The Morris water maze is widely used to study spatial memory and learning. Animals are placed in a pool of water that is colored opaque with powdered non-fat milk or non-toxic tempera paint, where they must swim to a hidden escape platform. Because they are in opaque water, the animals cannot see the platform, and cannot rely on scent to find the escape route. Instead, they must rely on external/extra-maze cues. As the animals become more familiar with the task, they are able to find the platform more quickly. Developed by Richard G. Morris in 1984, this paradigm has become one of the "gold standards" of behavioral neuroscience

An Analysis Of Virtual Place Learning/navigation In Children And Young Adults Prenatally Exposed To Alcohol

Fetal alcohol spectrum disorder refers to the spectrum of disorders resulting from prenatal alcohol exposure and is the leading cause of preventable mental retardation. Rodent studies have found that prenatal alcohol exposure impairs performance on the Morris water maze. This task requires the rodent to use distal room cues to locate a hidden platform in a pool of opaque water. Successful performance on this task is dependent upon hippocampal function. Rodents prenatally exposed to alcohol are impaired on the Morris water maze and show damage to hippocampal neurons. A human analogue of the Morris water maze, the virtual water maze has been created using computer-generated 3D virtual environments. Only one study has been conducted examining performance on the virtual water maze and FASD. This dissertation examined performance on the virtual water in three cohorts of individuals prenatally exposed to alcohol from Detroit and Cape Town, South Africa. Hypotheses were that children with a diagnosis of fetal alcohol syndrome or partial fetal alcohol syndrome, and those with a known history of prenatal alcohol exposure, but lacking the characteristic facial features will be impaired on the virtual water maze. Second, the amount of prenatal alcohol exposure will be negatively correlated with virtual water maze performance. Third, fetal alcohol-related reductions in hippocampal volume will mediate the relationship between FASD and virtual water maze performance. Lastly, prenatal alcohol related changes in testosterone will also mediate the relation between FASD and virtual water maze performance. Results indicated that both those with an FASD diagnosis were impaired on the virtual water maze. Degree of prenatal alcohol exposure was also correlated with poorer performance on the virtual water maze. These results were detected in the cohort with the heaviest levels of prenatal alcohol exposure. Right hippocampal volume was shown to be a mediator of the relation between FASD/prenatal alcohol exposure and virtual water maze performance. Testosterone was not related to virtual water maze performance. These data demonstrate that virtual water maze performance is sensitive to the effects of heavy prenatal alcohol exposure. Furthermore, impairments on this task may be due to fetal alcohol-related damage in the hippocampus

The effect of spatial learning on the number of astrocytes in the CA3 subfield of the rat hippocampus

Introduction: Astrocytes play an important role in the hippocampus, probably in memory and learning. The aim of this study was to evaluate the number of astrocytes in the CA3 subfield of the rat hippocampus after spatial learning using the Morris water maze with reference and working memory methods. Methods: 45 male albino wistar rats were divided into three groups, with 15 rats in the control group and 15 rats in each of the other two groups. The two study groups of rats underwent spatial learning using the Morris water maze, with one group trained using the reference memory and the other, the working memory technique, respectively. After histological processing, the slides of the brains were stained with the phosphotanguestic acid haematoxylin staining method for detection of the astrocytes. Results: There was a significant difference in the number of astrocytes in the CA3 area between the control and reference memory groups. The difference between control and working memory groups was significant as well. Additionally, when comparing the two learning groups, we also found significant differences between them. Conclusion: The number of astrocytes increased due to spatial learning

A STUDY ON NOOTROPIC ACTIVITY OF CELASTRUS PANICULATA WILLD WHOLE PLANT METHANOLIC EXTRACT IN RATS

Objective: The objective of the present study was to evaluate the nootropic activity of Celastrus paniculata Willd whole plant methanolic extract(CPPME) using different models.Methods: Nootropic activity in rats with the treatment of CPPME (100, 200, 400 mg/kg, oral.) and piracetam (200 mg/kg, i.p.) were administered todifferent groups of rats. Effect of drugs on learning and memory of rats was evaluated using elevated plus maze, morris water maze on scopolamine,and aluminum-induced amnesia models, and also estimated the brain acetylcholinesterase (AChE) concentration and the percentage of inhibition ofAChE.Results: CPPME shows significantly improved in learning and memory of rats, as indicated by the decline in transfer latency using elevated plusmaze and also decrease in escape latency during training and retrieval using morris water maze. Memory-enhancing activity of CPPME (100, 200,400 mg/kg, oral.) was comparable to piracetam (200 mg/kg, i.p.). CPPME, Mentat (Nootropic Herbal formulation), and piracetam also notably reducedbrain AChE concentration and increased the percentage of inhibition of AChE activity in rat brain.Conclusion: Thus, CPPME showed nootropic activity in rats probably by inhibiting brain AChE activity.Keywords: Nootropic activity, Celastrus paniculata Willd whole plant, Methanolic extract, Scopolamine-induced amnesia, Aluminum-induced amnesia,Spatial memory in Morris water maze test and acetylcholinesterase enzyme

Master of Science

thesisThe Morris water maze is a task adapted from the animal spatial cognition literature and has been studied in the context of sex differences in humans, particularly because of the standard design, which manipulates proximal (close) and distal (far) cues. However, there are mixed findings with respect to the interaction of cues and sex differences in virtual Morris water maze tasks, which may be attributed to variations in the scale of the space and previously unmeasured individual differences. We explore the question of scale and context by presenting participants with an outdoor virtual Morris water maze that is four times the size of the mazes previously tested. We also measured lifetime mobility and mental rotation skills. Results of this study suggest that for the small-scale environment, males and females performed similarly when asked to navigate with only proximal cues. However, males outperformed females when only distal cues were visible. In the large-scale environment, males outperformed females in both cue conditions. Additionally, greater mental rotation skills predicted better navigation performance with proximal cues only. Finally, we found that highly mobile females and males perform equally well when navigating with proximal cues

Working memory learning method and astrocytes number in different subfields of rat's Hippocampus

The aim of this study was evaluation of the astrocytes number in different subfields of rat's Hippocampus after spatial learning with usage of Morris Water Maze technique and working memory method. In this study, between 2005-2006 years in Pasteur institute of Iran-Tehran and histological department of Gorgan University with usage of Morris Water Maze and working memory technique, we used 14 male albino wistar rats. Seventh rats were in control group and 7 rats in working memory group. After histological preparation, the slides were stained with PTAH staining for showing the Astrocytes. Present results showed significant difference in astrocytes number in CA1, CA2 and CA3 areas of hippocampus between control and reference memory group. The number of astrocytes is increased in working memory group. Then we divided the hippocampus to three parts: Anterior, middle and posterior and with compare of different area (CA1, CA2 and CA3) of hippocampus, we found that the differences between Anterior-middle and Middle-Posterior of CA1 and CA2 area of hippocampus were significant, whereas the difference between Anterior-Posterior parts was not significant in CA1 and CA2 areas. In CA3 area, the difference between Anterior-Middle and Anterior-Posterior parts was significant, whereas the difference between middle and posterior parts was not significant. We concluded that the number of astrocytes increased due to spatial learning and working memory technique. © 2008 Science Publications