The Morris Water Maze test is a widely used and reliable method for assessing spatial learning and memory in rodents and has been used to assess long-term cognitive function after stroke.

Ace Therapeutics offers the Morris Water Maze test to assess spatial learning and memory abilities in rodent models of stroke. Our experimental data can accurately assess the animal's sense of spatial location and orientation, especially in terms of spatial localization.

Related Services

• Behavioral Assessment of Cognition & Emotion in Animal Models of Stroke

What is the Morris Water Maze Test?

Mice are excellent swimmers but they hate swimming. The Morris water maze exploits this to put rodent learning and memory to the test. In this test, animals are placed in an open circular pool filled with water and forced to swim. The pool is divided into four quadrants, with a platform hidden under the water in one quadrant. The water is colored with paint to prevent the hidden platform from being seen. Therefore, they are forced to use the spatial cues around them to determine their location and navigate to the platform to escape the water.

The standard protocol lasts five days, divided into four acquisition days and a probe trial day. Each day includes four trials, with a maximum duration of 60 seconds, where animals start from varying positions and never in the quadrant containing the platform. If an animal finds the platform, the trial ends; if not, the experimenter places it on the platform for 10-15 seconds to observe the environment. On the fifth day, the platform is removed, and animals participate in a probe trial for 60 seconds, with a computerized video tracking system used to quantify their performance.

Fig.1. Scheme of the Morris water maze. (Lissner, et al., 2021)

Readouts in Morris Water Maze Test

The latency to reach the platform serves as a primary readout for cognitive function, with increased latency indicating memory deficits and cognitive decline. Additionally, the time spent by animals in the target quadrant can also be measured as a supplementary metric. Automated video tracking software facilitates the visualization and analysis of various parameters, including the route taken by the animals, total swimming distance, and average swimming speed.

Advantages and Disadvantages of the Morris Water Maze Test

The main advantage of using the Morris water maze to test memory over other common behavioral mazes is this:

• The animal has no olfactory trail to find the target by odor tracking
• Animals do not need to be motivated by fasting
• Highly quantifiable data can be generated

However, this test requires long training trials and the training regimen may affect the animal's performance. In addition, the results are influenced by the animal's locomotor ability. Therefore, it is preferable to use this test on animals with similar swimming speeds. Alternatively, modifications can be made to obtain more reliable results.

Applications of the Morris Water Maze in Rodent Models of Stroke

The Morris Water Maze has been utilized to assess cognitive function following both ischemic and hemorrhagic strokes in rodents.

Applications of the Morris Water Maze in Rodent Models of Ischemic Stroke

• Mice with focal ischemic stroke exhibited increased latency in locating the hidden platform at 2, 4, and 6 weeks post-injury compared to sham controls, indicating cognitive decline.
• Similar results were observed in rats 12–14 weeks after ischemic stroke.
• Rats in enriched environments showed improved cognitive outcomes, spending less time finding the platform than those in deprived conditions.

Applications of the Morris Water Maze in Rodent Models of Hemorrhagic Stroke

• In an intracerebral hemorrhage (ICH) model, rats displayed increased swimming distance at 2 weeks but not at 8 weeks post-injury, indicating cognitive impairment in the chronic phase (<8 weeks).
• Swimming distance was preferred over latency as a measure because it accounts for variations in swimming speed that could affect results.
• In a subarachnoid hemorrhage (SAH) model, SAH rats showed increased escape latency at day 5 post-stroke and exhibited spatial learning deficits on days 4 and 5, alongside prolonged escape latency at days 29–35, reflecting long-term cognitive decline.
• Although less frequently used in mice, recent studies found that SAH mice also exhibited longer times to locate the hidden platform and spent less time in the target quadrant during probe trials, indicating spatial learning deficits up to 19 days after injury.

Fig.2. Morris water maze test of spatial learning and memory in BMSC-EV treated ischemic mice. (McEntire, et al., 2016)

1. Lissner, L. J., et al. (2021). Object recognition and Morris water maze to detect cognitive impairment from mild hippocampal damage in rats: A reflection based on the literature and experience. Pharmacology Biochemistry and Behavior, 210, 173273.
2. Deng, M., et al. (2017). Mesenchymal stem cell-derived extracellular vesicles ameliorates hippocampal synaptic impairment after transient global ischemia. Frontiers in cellular neuroscience, 11, 205.