The Morris water maze (MWM) is a widely used tool in neuroscience research for studying spatial learning and memory in rodents. However, optimizing MWM experiments requires a nuanced understanding of the protocol, the specific mouse strain, and the testing environment. This article provides a detailed guide on how to optimize your MWM experiments for the most accurate and reliable results.
Understanding the Morris Water Maze
The MWM is a large circular pool filled with opaque water, with a hidden escape platform submerged just below the surface. Rodents are placed in the pool and must use spatial strategies and local cues to find the hidden platform. The time taken to find the platform, known as escape latency, and the time spent in the quadrant where the platform was previously located during probe trials, are key measures of cognitive function and reference memory.
Tailoring the Experiment to the Mouse Strain
The background strain of the mouse model can significantly influence the observed behavioral phenotype. Some strains exhibit superior learning ability relative to others. Therefore, identifying a training procedure sensitive to the background strain is essential to detect differences between transgene-negative and transgene-positive mice.
Setting Up the Testing Environment
The testing room should be a quiet space with WiFi access and proper illumination. Spatial cues, such as different shapes cut out of colored paper, should be taped to the room’s walls. The maze should be set up several feet away from the experimenter’s seat to minimize distractions and interference.
Preparing the Water Maze
The tank should be filled so that the escape platform is one inch below the water’s surface. To make the water opaque, use non-fat dry milk or non-toxic white tempera paint. This ensures that the platform remains hidden, forcing the rodent to rely on spatial strategies and visual cues to locate it.
Conducting Training and Probe Trials
Rodents are initially given a series of learning trials, where they are allowed to swim in the tank until they find the hidden platform. Learning trials last a specific amount of time, but it is similarly important to specify the time between trials too.
After the learning trials, a probe trial is conducted. The submerged platform is removed, and the time the animal spends swimming in the quadrant where the platform was previously located is measured. Rodents that have learned the platform’s location will spend most of their time in this quadrant, while poor learners will search other areas of the tank.
Considering Alternative Tests
If the MWM is not suitable for your research, consider alternative tests for spatial learning and memory, such as the radial arm maze or the Barnes circular platform maze.
By following these tips and tricks, researchers can optimize their Morris Water Maze experiments to better assess spatial learning and memory in rodent models.
Looking Forward to Optimizing Your Spatial Learning Experiments?
At San Diego Instruments, we understand the complexities and nuances of conducting spatial learning experiments. Our expertise in this field has allowed us to develop tools that are tailored to the needs of researchers in this area, including our Morris Water Maze, which is ideal for testing rodent behavior and assessing spatial learning and memory.
Discover Our Morris Water Maze
Our Water Maze is available in both rat and mouse models, ensuring compatibility with your specific research needs. The maze is designed with seamless walls to eliminate inadvertent cues, enhancing the validity of your experiments. We offer clear platforms in both rectangular and round options, and they can be fixed or adjusted in height to suit your experimental design.
Furthermore, our Water Maze is compatible with our ANY-maze video tracking system, allowing for precise tracking and analysis of rodent behavior. We also provide an optional drain kit that fits any of SDI’s tanks, facilitating easy maintenance and cleaning of the maze.
Our Water Maze is constructed from durable, high-density polyethylene, ensuring its longevity and reliability in your lab. With a diameter of 48″ for the mouse model and 72″ for the rat model, our Water Maze provides ample space for your rodents to navigate and learn.
If you want to optimize your spatial learning experiments, we at San Diego Instruments are here to provide you with the tools and expertise you need. Our Morris Water Maze is just one example of how we can help enhance your research. For more information, please visit our product page.
References and further reading:
- Weitzner DS, Engler-Chiurazzi EB, Kotilinek LA, Ashe KH, Reed MN. Morris Water Maze Test: Optimization for Mouse Strain and Testing Environment. J Vis Exp. 2015 Jun 22;(100):e52706. doi: 10.3791/52706. PMID: 26132096; PMCID: PMC4545046.
- Nunez J. Morris Water Maze Experiment. J Vis Exp. 2008 Sep 24;(19):897. doi: 10.3791/897. PMID: 19066539; PMCID: PMC2872979.
- Weitzner DS, Engler-Chiurazzi EB, Kotilinek LA, Ashe KH, Reed MN. Morris Water Maze Test: Optimization for Mouse Strain and Testing Environment. J Vis Exp. 2015 Jun 22;(100):e52706. doi: 10.3791/52706. PMID: 26132096; PMCID: PMC4545046.