The Morris water maze (MWM) is commonly utilized in neuroscience studies for examining spatial learning and memory in rodents. Optimizing MWM experiments requires a nuanced understanding of the protocol, the specific mouse strain, and the testing environment. This article offers a comprehensive guide on enhancing MWM experiments for the most accurate and reliable results.
Understanding the Morris water maze
The MWM consists of a large circular pool filled with opaque water and a hidden escape platform submerged just below the surface. Rodents are placed in the pool and must use spatial strategies and environmental cues to locate the hidden platform.
Key measures of cognitive function and reference memory include the time taken to find the platform (escape latency) and the time spent in the quadrant where the platform was previously located during probe trials.
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Tailoring the experiment to the mouse strain
The mouse model’s background strain can significantly affect the observed behavioral phenotype, as some strains display superior learning abilities compared to others.
Identifying a training procedure sensitive to the background strain is crucial for detecting differences between transgene-negative and transgene-positive mice.
Setting up the testing environment
The testing room should be quiet, properly illuminated, and have WiFi access. Spatial cues, such as different shapes cut from colored paper, should be affixed to the room’s walls. To minimize distractions and interference, the maze must be set up several feet away from the experimenter’s seat.
Preparing the water maze
The tank must be filled with the escape platform submerged one inch below the water's surface. Non-fat dry milk or non-toxic white tempera paint can be added to the water to make it opaque. This ensures that the platform remains concealed, forcing the rodent to depend on spatial strategies and visual cues to find it.
Conducting training and probe trials
Rodents initially undergo a series of learning trials, during which they are allowed to swim in the tank until they locate the hidden platform. Learning trials last a certain amount of time, but it is equally important to specify the time between trials.
Following the learning trials, a probe trial is performed in which the submerged platform is eliminated, and the time the animal spends swimming in the quadrant where the platform was previously located is recorded.
Rodents who have learned the platform’s location will spend most of their time in this quadrant, whereas poor learners will search other areas of the tank.
Considering alternative tests
If the MWM is not ideal for your study, alternative tests for spatial learning and memory can be considered, such as the radial arm maze or the Barnes circular platform maze.
By following these tips and tricks, scientists can optimize their MWM experiments to evaluate spatial learning and memory in rodent models more effectively.
Discover San Diego Instruments’ Morris water maze
The MWM is available in rat and mouse models, guaranteeing compatibility with specific research requirements. It is designed with seamless walls to eliminate unintended cues, improving the reliability of experimental results. Clear platforms are provided in rectangular and round options, with fixed or adjusted heights to meet varied experimental designs.
It is compatible with the ANY-maze video tracking system, enabling accurate tracking and analysis of rodent behavior. An optional drain kit that fits any of San Diago Instruments’ tanks is available, allowing for easy maintenance and maze cleaning.
Constructed from durable, high-density polyethylene, the MWM is designed for longevity and reliability in the laboratory environment. With a diameter of 48″ for the mouse model and 72″ for the rat model, it provides ample space for rodents to navigate and learn.
San Diego Instruments has the tools and expertise needed for optimized spatial learning environments.
References and further reading
- Weitzner, D.S., et al. (2015). Morris Water Maze Test: Optimization for Mouse Strain and Testing Environment. Journal of Visualized Experiments, (100). https://doi.org/10.3791/52706.
- Nunez, J. (2008). Morris Water Maze Experiment. Journal of Visualized Experiments, (19). https://doi.org/10.3791/897.
About San Diego Instruments, Inc.
For more than 30 years, San Diego Instruments has served the scientific community as a comprehensive resource for the design, manufacture and distribution of behavioral neuroscience research instruments used in human and animal studies. Utilized in laboratories and cited in research papers worldwide, SDI systems have come to represent the industry standard for quality and longevity. Our premier SR-LAB™ is the world’s most widely used startle response system. At SDI, our commitment to developing quality products that stand the test of time is matched only our dedication to excellent customer service. We take pride in our ever-growing core of loyal clientele.
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