The Morris water maze is the most widely used test of spatial learning and memory in rodents, and also one of the most frequently misapplied. This note summarises what the task measures and the setup details that decide whether results replicate between laboratories.
What the task measures
The animal learns the position of a hidden platform from distal spatial cues. Escape latency on acquisition trials therefore reflects spatial learning, while the probe trial, in which the platform is removed, reflects the strength of the spatial memory itself. Swim speed and thigmotaxis must be reported alongside latency, because otherwise a difference in latency can be produced by a difference in motor performance or anxiety rather than by memory.
Setup details that matter
Water temperature should be held constant and recorded; unstable temperature is a common cause of drifting escape latencies. Opacifier must be mixed thoroughly so that the platform cannot be seen, the pool must be level, and distal cues must stay fixed for the whole experiment. Quadrant boundaries and the platform zone should be defined once in the tracking software and reused for every animal in the cohort.
Reporting
Export per-trial latency, path length, swim speed and thigmotaxis together with the tracking configuration so that the experiment can be reproduced, and keep arena and zone maps with the experiment file.