Alzheimer's disease is a neurodegenerative disease that is characterized by the accumulation of two different proteins, β-amyloid and tau. The objective of the present study was to examine the impact of bilateral administration of the cannabinoid receptor antagonist (AM251) in the hippocampus on spatial memory and tau gene expression in an Alzheimer's disease model. The β-amyloid toxin was administered bilaterally into the hippocampus of Wistar male rats to induce Alzheimer's disease. The rats were then divided into four groups: the control group (which received distilled water as a solvent for β-amyloid toxin), the lesion group (which received the β-amyloid), β-amyloid + DMSO group (as antagonist solvent), and the AM251 antagonist receiving groups. During the training course of the Morris water maze test, the antagonist of the cannabinoid 1 receptor antagonist AM251 was administered bilaterally into the hippocampus for four consecutive days at doses of 5, 25, and 100 ng. To evaluate the spatial memory of the animals, the following parameters were analyzed: distance traveled, latency time to reach the hidden platform, velocity of the animals, and tau gene expression in real time. The spatial memory indices were found to be impaired following the injection of β-amyloid and the AM251 cannabinoid antagonist. Following the injection of β-amyloid toxin, there was an increase in mRNA expression of tau protein. However, no significant difference was observed between the cannabinoid antagonist and β-amyloid groups. These results indicate that β-amyloid toxin has a destructive effect on spatial memory and that cannabinoid system plays a positive role in memory formation and consolidation, However, further studies are needed to confirm these findings.

Huntington's disease (HD) is a neurodegenerative disorder characterized by cognitive deficits and motor function. Levothyroxine (L-T4) is a synthetic form of Thyroxine (T4), which can improve cognitive ability. The aim of the present study was to determine the neuroprotective effect of L-T4 administration in rats with 3-nitropropionic acid (3-NP)-induced Huntington's disease. Forty-eight Wistar male rats were divided into six groups (n = 8): Group 1 control group that received physiological saline, Group 2 and 3: which received L-T4 (30 and 100μg/kg), Group 4: HD group that received 3-NP and Groups 5 and 6: The treatment of the HD rats with L-T4 (30 and 100μg/kg). Spatial memory, locomotor activity, and frequency of neuronal firing were assessed. After decapitation, the Brain-Derived Neurotrophic Factor (BDNF) and Total antioxidant capacity (TAC) levels in the striatum was measured. The results showed that the indices of spatial memory (mean path length and latency time) and motor dysfunction (immobility time) significantly increased, while time spent in the goal quadrant, swimming speed, spike rate, and striatum levels of BDNF significantly decreased in the HD group compared to the control group. L-T4 treatment significantly enhanced time spent in the goal quadrant, swimming speed, motor activity (number of line crossing and rearing), spike rate and striatal BDNF level. This research showed that L-T4 prevented the disruption of motor activity and cognitive deficiencies induced by 3-NP. The beneficial effects of L-T4 may be due to an increase in the concentration of BDNF and enhancement of the spike rate in the striatum.

Objective: The use of xenobiotics to boost agricultural productivity has led to toxic chemicals exposure including organophosphates, causing adverse health outcomes including behavioral and neuronal impairments. This study aimed to evaluate the memory indices, possible oxidative and cholinesterase outturnson the frontal cortices of rats exposed to organophosphates.Methodology: Thirty-two Wistar rats were grouped into four. They received 1ml/kg of Normal, 8.8 mg/kg dichlorvos, 14.9 mg/kg chlopyrifos, and 8.8 mg/kg dichlorvos plus 14.9mg/kg chlorpyrifos respectively. They had training trials in the Y Maze paradigm then spatial working memory assessment. They were euthanized 24hours following exposure and tissues excised for analysis.Results: A marked reduction in metabolic markers, Acetylcholine Esterase (AChE) activity, spatial memory indices and proliferative neuron marker (Ki67) were observed. Also, increase in oxidative stress markers in the frontal cortices of the organophosphates exposed rats.Conclusion: The findings demonstrated neurotoxic effects of organophosphates in rats.

The prime concern of this study is to simulate the joint effect for the presence of two fractional derivative parameters (memory indices) by providing a novel analytical solution scheme for the fractional initial value problems. Our goal has been fulfilled by extending the residual power series method into the two-dimensional time and space, with time and space endowed with fractional derivative orders $$\alpha $$ and $$\gamma $$ , respectively (simply denoted by fractional $$(\alpha ,\gamma )$$ -space), by virtue of a new $$(\alpha ,\gamma )$$ -fractional power series representation ( $$(\alpha ,\gamma )$$ -FPS). The necessary theoretical framework for the convergence and the error bound is also provided to enrich our analytical study. Among other main findings, it is deserved to mention that the fractional derivative parameters act like the homotopy parameters, in a topological sense, to generate a rapidly convergent series solution for the classical integer version of the problem under consideration, which promotes the idea that these parameters describe a remnant memory. The efficiency of the proposed approach is assessed by projecting the obtained solutions of several well-known (non)linear problems into lower-dimensional fractal space and/or into integer space and then comparing them with the corresponding results of the literature. Overall, the method shows a wide versatility and adequacy in dealing with such hybrid problems.

In recent years, there have been many works devoted to the study of the effects of sex hormones on cognitive function. Clinical studies have found that inmenopausal women, the tendency to develop type 2 diabetes will increase, the spatial and short-term working memory worsens, and there is a tendency to develop depression. The findings suggest that estrogens are involved in the mechanisms of insulin resistance in tissues, in the synthesis of mediators in the catecholaminergic systems of the brain, but many questions remain unresolved. Therefore, the aim of our study was to establish the effect of estrogens on the indices of spatial memory in ovariectomized and old rats against the background of the development of experimental diabetes. The study was conducted on 30 adult rats females 4-5 months and 20 months. The study groups were ovariectomized and reproduced experimental type 2 diabetes mellitus with protamine sulfate. The study of spatial memory was carried out in an eight-sleeved radial labyrinth. Results and conclusions: Ovariectomy caused the deterioration of spatial memory relative to the living control group, and diabetes mellitus aggravated pathological changes. The changes that occur after ovariectomy suggest estrogen involvement in the regulation of cognitive functions.

Clozapine blockade of MK-801-induced learning/memory impairment in the mEPM: Role of 5-HT1A receptors and hippocampal BDNF levels

Sex, estradiol, and spatial memory in a food-caching corvid

Measure of anxiety-related behaviors and hippocampal BDNF levels associated to the amnesic effect induced by MK-801 evaluated in the modified elevated plus-maze in rats

Reliable neuropsychological markers of right temporal integrity have proven elusive. Specifically it is unclear whether figural and spatial aspects of visual memory are differentially affected by right temporal lobe epilepsy (TLE) and subsequent resection. To investigate this we used the modified Rey Complex Figure (RCF) scoring system devised by Brier et al. (1996) to obtain separate indices of figural and spatial memory in TLE surgery candidates. We extended on their study by examining presurgical performance and change following right and left temporal lobectomy (RATL, n = 38, LATL, n = 42) in individuals from a cross-institutional sample with and without hippocampal sclerosis (HS(+)/HS(-)). Contrary to expectation neither figural nor spatial RCF recall were differentially sensitive to RTLE, right HS, or subsequent resection. Presurgically, laterality effects on both figural and spatial memory indices were not found although HS(-) individuals significantly outperformed HS(+) individuals on both measures. Following surgery the largest decrements in both figural and spatial recall were observed among LATL HS(-) participants. We concluded that RCF recall is a poor marker of right temporal lobe function and suggest it may be a "surrogate" measure of left temporal lobe function possibly due to the verbalizability of many of its components.

Evidence that muscarinic receptors are involved in nicotine-facilitated spatial memory

200 pairs of twins were assessed at 14 months of age in the laboratory and home. Measures were obtained of temperament, emotion, and cognition/language. Comparisons between identical and fraternal twin correlations suggest that individual differences are due in part to heritable influences. For temperament, genetic influence was significant for behavioral observations of inhibition to the unfamiliar, tester ratings of activity, and parental ratings of temperament. For emotion, significant genetic influence was found for empathy and parental ratings of negative emotion. The estimate of heritability for parental report of expression of negative emotions was relatively high, whereas that for expression of positive emotions was low, a finding consistent with previous research. For cognition and language, genetic influence was significant for behavioral indices of spatial memory, categorization, and word comprehension. Shared rearing environment appears influential for parental reports of language and for positive emotions, but not for other measures of emotion or for temperament.