A robust bitmap-based real-time position tracking algorithm for rats in radial arm maze tests

This paper aims to develop a position tracking algorithm by which a rat in a radial arm maze can be accurately located in real time. An infrared (IR) night-vision camera was hung above the maze to capture IR images of the rat. The IR images were binarized and then duplicated for subsequent intersection and opening operations. Due to simple operations and a high robustness against the noise spots formed by the droppings of the rat, it took just minutes to process more than 9000 frames, and an accuracy above 99% was reached as well. The maze was intruded by an experimenter to further test the robustness, and the accuracy slightly fell to 98%. For comparison purposes, the same experiments were carried out using a pre-trained YOLO v2 model. The YOLO counterpart gave an accuracy beyond 97% in the absence and in the presence of the intruder. In other words, this work slightly outperformed the YOLO counterpart in terms of the accuracy in both cases, which indicates the robustness of this work. However, it took the YOLO counterpart an hour or so to locate a rat contained in the frames, which highlights the contribution of this work.

The Effects of Acute and Binge 3,4-methylenedioxymethamphetamine (MDMA) Exposure on Learning and Memory in Rats

<p>When rats are administered acute doses of MDMA they produce significantly more reference memory errors than working memory errors in the partially baited radial arm maze (Kay et al, 2009). The potential role of serotonin and dopamine in this effect was examined by administering the serotonin agonist Citalopram and the dopamine agonist GBR12909. GBR12909 produced significantly more reference memory errors, while Citalopram tended to produce more working memory errors. Administration of the D1 agonist A68930 and the D2 agonist Quinpirole predominantly produced reference memory errors, but to a lesser extent than acute MDMA administration. Low doses of both drugs produced a synergistic effect, more similar to that seen with acute MDMA administration. These findings suggest dopamine plays a role in the reference memory effect seen with MDMA exposure in the partially baited radial maze. In the second half of the thesis binge regimes of MDMA (4 x 10mg/kg) were administered to rats. When there was a gap of eight weeks between dosing and training the ability to acquire the radial arm maze was not significantly impaired. When this MDMA regime was repeated with a three-day gap between dosing and training it produced a significant but transient deficit in performance. When later challenged with acute doses of MDMA (4.0 mg/kg) the binge treated rats were less impaired than saline controls indicating drug tolerance. In an additional study that used a three-day delay between dosing and training a significant impairment in task acquisition was found. This deficit appeared to be long-term as the MDMA treated rats were impaired when the rules of task were changed suggesting a deficit in cognitive flexibility. Again when subjects were challenged with acute MDMA there was evidence of drug tolerance. The final study examined the effects of repeated MDMA exposure on task acquisition by administering acute doses of MDMA or saline once a week after rats had previously been treated with either a binge regime of MDMA or saline. MDMA exposure significantly impaired task acquisition and produced residual drug effects in the binge treated MDMA group the day after acute drug administration. However evidence of behavioural tolerance in this study was mixed due to a floor effect where performance of the binge MDMA group was so poor at the beginning of the study. In conclusion MDMA exposure impaired accuracy with reference memory processes were more affected than working memory processes. The underlying nature of this impairment remains unclear but it may be due to a long-term memory deficit, an impairment in understanding task rules or a perseverative pattern of responding. These findings imply human Ecstasy users may show deficits in acquiring information and may experience deficits in cognitive flexibility</p>

The Effects of Acute and Binge 3,4-methylenedioxymethamphetamine (MDMA) Exposure on Learning and Memory in Rats

<p>When rats are administered acute doses of MDMA they produce significantly more reference memory errors than working memory errors in the partially baited radial arm maze (Kay et al, 2009). The potential role of serotonin and dopamine in this effect was examined by administering the serotonin agonist Citalopram and the dopamine agonist GBR12909. GBR12909 produced significantly more reference memory errors, while Citalopram tended to produce more working memory errors. Administration of the D1 agonist A68930 and the D2 agonist Quinpirole predominantly produced reference memory errors, but to a lesser extent than acute MDMA administration. Low doses of both drugs produced a synergistic effect, more similar to that seen with acute MDMA administration. These findings suggest dopamine plays a role in the reference memory effect seen with MDMA exposure in the partially baited radial maze. In the second half of the thesis binge regimes of MDMA (4 x 10mg/kg) were administered to rats. When there was a gap of eight weeks between dosing and training the ability to acquire the radial arm maze was not significantly impaired. When this MDMA regime was repeated with a three-day gap between dosing and training it produced a significant but transient deficit in performance. When later challenged with acute doses of MDMA (4.0 mg/kg) the binge treated rats were less impaired than saline controls indicating drug tolerance. In an additional study that used a three-day delay between dosing and training a significant impairment in task acquisition was found. This deficit appeared to be long-term as the MDMA treated rats were impaired when the rules of task were changed suggesting a deficit in cognitive flexibility. Again when subjects were challenged with acute MDMA there was evidence of drug tolerance. The final study examined the effects of repeated MDMA exposure on task acquisition by administering acute doses of MDMA or saline once a week after rats had previously been treated with either a binge regime of MDMA or saline. MDMA exposure significantly impaired task acquisition and produced residual drug effects in the binge treated MDMA group the day after acute drug administration. However evidence of behavioural tolerance in this study was mixed due to a floor effect where performance of the binge MDMA group was so poor at the beginning of the study. In conclusion MDMA exposure impaired accuracy with reference memory processes were more affected than working memory processes. The underlying nature of this impairment remains unclear but it may be due to a long-term memory deficit, an impairment in understanding task rules or a perseverative pattern of responding. These findings imply human Ecstasy users may show deficits in acquiring information and may experience deficits in cognitive flexibility</p>

Hydrolase-Treated Royal Jelly Attenuates H2O2- and Glutamate-Induced SH-SY5Y Cell Damage and Promotes Cognitive Enhancement in a Rat Model of Vascular Dementia

Vascular dementia (VaD) is the second most common type of dementia following Alzheimer’s disease, but the therapeutic efficacy is still not effective. This makes the searching for novel neuroprotective agents important. Therefore, we hypothesized that royal jelly, a well-known traditional medicine, could attenuate memory impairment and brain damage in vascular dementia. This study determined the effects of royal jelly hydrolysate (RJH) and possible mechanism of cell damage and cognitive-enhancing effect in animal study. An in vitro study assessed the effects of RJH on acetylcholinesterase inhibitor, cell viability, and cell damage in SH-SY5Y neuroblastoma cells. Then, an in vivo study examined vascular dementia by the occlusion of the right middle cerebral artery (Rt.MCAO); adult male Wistar rats had been orally given RJH at doses ranging from 10, 50, to 100 mg/kg for 14 days before and 14 days after the occlusion of Rt.MCAO to mimic the VaD condition. Rats’ spatial memory was evaluated using Morris water maze and radial arm maze every 7 days after Rt.MCAO throughout a 14-day experimental period, and then, they were sacrificed and the acetylcholinesterase (AChE) activity in the hippocampus was determined. The results showed that RJH has no cytotoxic effect with the final concentration up to 500 μg protein/ml and reduces cell death from the H2O2- and glutamate-induced cell damage in in vitro neuroblastoma cells. Importantly, RJH significantly improved memory performance in Morris water maze test and radial arm maze and decreased the level of acetyl cholinesterase activity. In conclusion, RJH is the potential neuroprotective agent and cognitive enhancer for VaD.

Improvement of memory deficits via acetylcholinesterase inhibitory activity of Nepeta nuda ssp. nuda essential oil in rats

Nepeta L. (Lamiaceae) species are belonging to aromatic and medicinal plants. Many biological activities of Nepeta species have been reported. In this study, memory-enhancing activities of Nepeta nuda ssp. nuda essential oil was aimed to be evaluated in laboratory rats treated with scopolamine. GC-MS/GC-FID system was used to identify oil composition. Memory performances of the rats were tested using Y-maze and radial-arm maze. Acetylcholinesterase enzyme activity and molecular docking analysis were also performed in this study. In total, 44 different compounds were identified in Nepeta nuda ssp. nuda essential oil. Trans-cis nepetalactone was showed to be the most abundant constituent in the oil. In the Y-maze test, the oil improved the performances of the animals on spontaneous alternation. Besides, in the radial-arm maze test, the oil improved working and reference memory significantly impaired in the rats subjected to scopolamine. The oil also showed acetylcholinesterase inhibitory activity in vitro. The molecular docking method, in the meantime, revealed that some of the compounds in the oil could interact with the acetylcholinesterase enzyme, theoretically. Nepeta nuda ssp. nuda essential oil improved spatial memory of scopolamine-induced rats. Neuroprotective effects of the oil are probably related to the anti-cholinesterase activity of the oil. Therefore, Nepeta nuda ssp. nuda essential oil could be used as a complementary therapy to improve memory in Alzheimer’s and related diseases.

Experimental Evaluation of Vitamin - D Supplementation on Memory and Learning Using Different Animal Models in Albino Rat

Aim: We conducted this study with the aim to investigate the effect of vitamin D3 on spatial learning and memory in healthy young albino rat. Study Design: Experimental evaluation. Place and Duration of Study: Department of Pharmacology, Smt. Kashibai Navale Medical College and General Hospital (SKNMCGH), Pune, between October 2019 to February 2020. Methodology: All the pharmacological experiments were conducted using Wistar albino rats (n=6), weighing between 100 g – 150 g. Total 18 animals (9 male and 9 female) were screened and marked into 3 different groups (6 in each group) Control (Normal saline 10 ml/kg), Vitamin D (Cholecalciferol 1000 IU/kg) and standard (Piracetam 200 mg/kg). Drugs were administered per os for 21 days. Elevated Plus Maze (Transfer Latency), Open Field Test (Rearing, Locomotion), Radial Arm Maze (Working and Reference memory) were used as amnesic models and their parameters for evaluation of this study. Results: After 21 days of treatment among all the three groups, Transfer Latency (p=9.55) in elevated plus maze, Working memory (p=0.454) and Reference memory (p=0.929) observed in radial 8 arm maze were non significant. In open field apparatus pellets count was significant (0.010), rest all parameters were non significant. Conclusion: The result of study suggests that no significant beneficial effect of Vitamin D was seen on various learning models as assessed by Elevated Plus Maze, Radial Arm Maze, Open Field Test.

Astragaloside IV suppressed hippocampal GABAergic synaptic transmission and enhanced memory through EGR-1 mediated BDNF/TrkB signaling pathway in mice

Background: Astragaloside IV (ASIV) is one of the saponins isolated from Astragalus membranaceus, a widely used traditional Chinese medicine and a health product sold all over the world. However, so far, the effect of ASIV on GABAergic synaptic transmission has not been elucidated yet. In the present study, the effect of ASIV on memory and hippocampal GABAergic synaptic transmission was investigated in wild type and early growth response protein 1 (EGR-1) knockout mice. Methods: Behavioral tests including radial-arm maze test and shuttle-box test, liquid chromatography-tandem mass spectrometry, western blotting analysis, quantitative PCR, electrophysiological recording, and electron microscopy were used in this study. Results: ASIV was shown to enhance the learning and memory of mice in behavioral tests, such as radial-arm maze test and shuttle-box test. It significantly reduced the concentration of GABA, the expression of glutamate decarboxylase 2 (GAD65) as well as the ratio of inhibitory synapses in mouse hippocampus, which was accompanied with a suppression of hippocampal spontaneous inhibitory postsynaptic currents. ASIV administration decreased the expression of EGR-1, brain-derived neurotrophic factor (BDNF) and tyrosine receptor kinase B (TrkB) in the hippocampus. Furthermore, blockage of BDNF/TrkB signaling with K-252a abrogated the effect of ASIV on GAD65 expression. When EGR-1 was knocked out, the promotive effects of ASIV on learning and memory, as well as the inhibitory effects on GABAergic synaptic transmission and GAD65, BDNF and TrkB expression, were abolished. In addition, ASIV was found to down-regulate the pre-existing EGR-1 baseline to better adapt to the learning stimuli. Conclusions: Together, these results demonstrated a novel role of ASIV in enhancing memory and reducing hippocampal GABAergic synaptic transmission through EGR-1 mediated BDNF/TrkB signaling pathway in mice.

Aqueous Root Bark Extract of Daniellia oliveri (Hutch. & Dalz.) (Fabaceae) Protects Neurons against Diazepam-Induced Amnesia in Mice

Daniellia oliveri (DO) is a traditional medicinal plant used for the treatment of diseases such as inflammation, schizophrenia, and epilepsy in Nigeria, Kenya, Congo, and Cameroon. This study was carried out to evaluate the potential neuroprotection effect of the aqueous root bark extract of Daniellia oliveri against diazepam-induced amnesia in mice. Thirty-six adult male mice were distributed into six groups: the three test groups received Daniellia oliveri root bark extract (100, 200, and 300 mg/kg), the normal control group received distilled water (10 ml/kg), a positive control group received piracetam (150 mg/kg), and the negative control received diazepam (2.5 mg/kg). Learning and memory were evaluated using the radial arm maze and the T-maze. Biomarkers of oxidative stress were also quantified in mice brains. Statistical analyses were performed using two-way ANOVA followed by Tukey’s post hoc test. Daniellia oliveri root bark aqueous extract decreased the number of working memory errors and number of reference memory errors in amnesic mice evaluated in the radial arm maze. Also, an increase in glutathione activity and a decrease in malondialdehyde levels were noted in the hippocampi homogenate of the extract-treated mice as compared to the diazepam-demented but untreated group. Moreover, pretreatment with Daniellia oliveri aqueous root bark extract reversed the decrease in hippocampal cell density observed in the nontreated diazepam group. Taken together, these results suggest that the aqueous extract of DO leaves possesses antioxidant potential and might provide an opportunity for the management of neurological abnormalities in amnesic conditions.