scholarly journals Morris Water Maze and Contextual Fear Conditioning Tasks to Evaluate Cognitive Functions Associated With Adult Hippocampal Neurogenesis

2022 ◽  
Vol 15 ◽  
Author(s):  
Karina Hernández-Mercado ◽  
Angélica Zepeda

New neurons are continuously generated and functionally integrated into the dentate gyrus (DG) network during the adult lifespan of most mammals. The hippocampus is a crucial structure for spatial learning and memory, and the addition of new neurons into the DG circuitry of rodents seems to be a key element for these processes to occur. The Morris water maze (MWM) and contextual fear conditioning (CFC) are among the most commonly used hippocampus-dependent behavioral tasks to study episodic-like learning and memory in rodents. While the functional contribution of adult hippocampal neurogenesis (AHN) through these paradigms has been widely addressed, results have generated controversial findings. In this review, we analyze and discuss possible factors in the experimental methods that could explain the inconsistent results among AHN studies; moreover, we provide specific suggestions for the design of more sensitive protocols to assess AHN-mediated learning and memory functions.

F1000Research ◽  
2014 ◽  
Vol 3 ◽  
pp. 193 ◽  
Author(s):  
Ivar S. Stein ◽  
Michaela S. Donaldson ◽  
Johannes W. Hell

Learning and memory as well as long-term potentiation (LTP) depend on Ca2+ influx through the NMDA-type glutamate receptor (NMDAR) and the resulting activation of the Ca2+ and calmodulin-dependent protein kinase (CaMKII). Ca2+ influx via the NMDAR triggers CaMKII binding to the NMDAR for enhanced CaMKII accumulation at post-synaptic sites that experience heightened activity as occurring during LTP. Previously, we generated knock-in (KI) mice in which we replaced two residues in the NMDAR GluN2B subunit to impair CaMKII binding to GluN2B. Various forms of LTP at the Schaffer collateral synapses in CA1 are reduced by 50%. Nevertheless, working memory in the win-shift 8 arm maze and learning of the Morris water maze (MWM) task was normal in the KI mice although recall of the task was impaired in these mice during the period of early memory consolidation. We now show that massed training in the MWM task within a single day resulted in impaired learning. However, learning and recall of the Barnes maze task and contextual fear conditioning over one or multiple days were surprisingly unaffected. The differences observed in the MWM compared to the Barnes maze and contextual fear conditioning suggest a differential involvement of CaMKII and the specific interaction with GluN2B, probably depending on varying degrees of stress, cognitive demand or even potentially different plasticity mechanisms associated with the diverse tasks.


Author(s):  
Ch Venkataramaiah ◽  
G Swathi ◽  
W Rajendra

 The morris water maze (MWM) was developed by morris as a device to investigate spatial learning and memory in laboratory rats. MWM has become one of the most frequently used laboratory tools in behavioral neuroscience. The MWM task has been often used in the validation of rodent models for neurocognitive disorders (e.g., Parkinson, Alzheimer, Epilepsy, and Schizophrenia), and the evaluation of possible neurocognitive treatments. It is also being used to assess the properties of established potential antipsychotics in animal models of Schizophrenia. The MWM task requires rats to find a hidden platform in a large, circular pool of water that is colored opaque with powdered non-fat milk (or) non-toxic tempera paint where they must swim to the hidden platform. Because they are in the opaque water, the animals cannot see the platform and cannot rely on scent to find the escape route. Instead, they must rely on extra-maze cues. The behavior of rat can be evaluated by analyzing the different parameters such as escape latency, swim speed, and path length, and probe trail. The purpose of this review is to briefly describe procedural aspects, interpretational difficulties of data and advantages of MWM. This paradigm has become a benchmark test for learning and memory difficulties in animal models and preclinical research in general.


2020 ◽  
Vol 178 (2) ◽  
pp. 347-357
Author(s):  
Muhammad M Hossain ◽  
Abdelmadjid Belkadi ◽  
Sara Al-Haddad ◽  
Jason R Richardson

Abstract Deficits in learning and memory are often associated with disruption of hippocampal neurogenesis, which is regulated by numerous processes, including precursor cell proliferation, survival, migration, and differentiation to mature neurons. Recent studies demonstrate that adult born neurons in the dentate gyrus (DG) in the hippocampus can functionally integrate into the existing neuronal circuitry and contribute to hippocampal-dependent learning and memory. Here, we demonstrate that relatively short-term deltamethrin exposure (3 mg/kg every 3 days for 1 month) inhibits adult hippocampal neurogenesis and causes deficits in learning and memory in mice. Hippocampal-dependent cognitive functions were evaluated using 2 independent hippocampal-dependent behavioral tests, the novel object recognition task and Morris water maze. We found that deltamethrin-treated mice exhibited profound deficits in novel object recognition and learning and memory in water maze. Deltamethrin exposure significantly decreased bromodeoxyuridine (BrdU)-positive cells (39%) and Ki67+ cells (47%) in the DG of the hippocampus, indicating decreased cellular proliferation. In addition, deltamethrin-treated mice exhibited a 44% decrease in nestin-expressing neural progenitor cells and a 38% reduction in the expression of doublecortin (DCX), an early neuronal differentiation marker. Furthermore, deltamethrin-exposed mice exhibited a 25% reduction in total number of granule cells in the DG. These findings indicate that relatively short-term exposure to deltamethrin causes significant deficits in hippocampal neurogenesis that is associated with impaired learning and memory.


2015 ◽  
Vol 2015 ◽  
pp. 1-6 ◽  
Author(s):  
Nawel Yagoubi ◽  
Yosra Jomni ◽  
Mohsen Sakly

The aim of this study was to characterize a novel animal model hyperthermia-induced febrile seizure and to investigate the impacts of repetitive febrile seizures on spatial learning and memory performances in immature rats.Methods. Rats were subjected to hyperthermia exposure one, two, or three times in 10-day intervals during 30 min in a water bath warmed at 45–50°C and their behaviour was monitored. Morris water maze spatial learning and memory were examined for control and treated groups. Results showed that rats subjected to 30-minute hyperthermia hot water developed rapidly myoclonic jerks and then generalized seizures. After a single hyperthermia exposure, the time for generalised tonic-clonic seizures appearance was 16.08 ± 0.60 min and it decreased gradually with repetitive exposure to reach 12.46 ± 0.39 min by the third exposure. Febrile seizures altered the spatial learning and memory abilities in Morris water maze and increased the time spent to attain the platform after one or two exposures, while after a third exposure rats exhibited the same latency compared to controls. Similar results were obtained in probe test where rats, subjected to hyperthermia for one or two episodes, spent less time in the target quadrant compared to corresponding controls. Further, when platform was moved from northwest to southwest quadrant, memory transfer test indicated that after one or two hyperthermia exposures cognitive performances were slightly altered, while after a third exposure the latency to escape increased significantly compared to untreated group. It was concluded that 30 min of hyperthermia hot water was sufficient to induce febrile seizures in immature rats and an increase of susceptibility was observed with repetitive hyperthermia exposure. Hyperthermia treatment impaired cognitive performances but the effects were mostly transient and moderate.


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