Constructing and Implementing a Low-Cost On-Demand Morris Water Maze Platform

The Morris water maze (MWM) is one of the most widely used procedures to assess hippocampus-dependent spatial learning and memory in rodents. By varying test protocols, researchers can test several different domains of learning and memory. Over multiple testing days, animals learn to swim to a platform hidden just under the water surface by using the spatial relationship between distal cues and the platform. Probe trials, where the platform is rendered unavailable, measure rodents' spatial bias for the area where the platform was previously located. The ability of researchers to control the availability of the platform "on-demand" offers both practical and methodological advantages. Despite MWM's prominence in the field of behavioral neuroscience, the high cost of purchasing a commercial MWM package is often prohibitively expensive for many research labs, especially on-demand platforms. Here, we describe a low-cost strategy for a build-your-own MWM that includes a remote-controlled on-demand platform (~530 USD) and tank (~550 USD). It is our hope that disseminating low-cost strategies aimed at expanding access to high-quality research tools at underfunded research institutions will accelerate biomedical discovery and foster further innovation. Key features • An on-demand platform allows for seamless testing (e.g., during probe trials, when the platform is usually removed), without interrupting the experiment to adjust/remove the platform. • The focus here is to offer a step-by-step, economical alternative to otherwise costly, commercial on-demand platforms. • Additionally, the protocol offers cost-effective ways of assembling the tank, preparing the testing environment, and implementing a testing protocol. • We include testing strategies specifically developed for aged rats, as these animals are routinely used in our laboratories.