[Experimental techniques for developing new drugs acting on dementia (7)--A water-finding task for use with mice:...

This article describes a water-finding (WF) task for use with mice in which the animals are not required to perform a special behavior and are not reinforced positively by water or feed during the training stage. The test apparatus consists of a rectangular open field with an alcove in the middle of one of the long walls of the enclosure. A metal drinking tube is inserted into the center of the alcove ceiling. Nonwater-deprived mice are placed individually into the test apparatus and are allowed to explore the environment freely during the training trial. In the test session, each mouse is placed back into this environment and the time between onset of exploration and initiation of drinking from the water tube is scored as a drinking latency. Learning is inferred if the animal finds the water tube more rapidly than an animal that had not been exposed previously to this environment. At that time, the WF task provides a measure of memory related mainly to the spatial construction of the test apparatus and to the specific object (water tube) in it. The water-finding performance during the test trial is thought to be based on latent learning, because the animals are deprived of water only before the test trial in order to promote recall of the location of the water tube to which they had been exposed in the training trial. Thus, the WF task may be advantageous in evaluating memory without manipulating reinforcers, although it can be improved upon.