[The assessment of drug effects on memory in animals]

The methodology of experiments on animal memory for the preclinical evaluation of cognition enhancers was reviewed. Representative experiments such as passive avoidance, the radial-arm maze, and delayed response are described. From the viewpoint of the predictability of drug effects in humans, the usefulness and the problems associated with these experiments are discussed. For example, such problems as the significance of response latency in the passive avoidance experiment, the innate robustness of the behavior in the radial-arm maze experiment, and the stability of the behavioral baseline in the delayed response experiment were noted. As for future directions, three issues are proposed: the importance of the descriptive principle in evaluating the data, the systematic construction of the testing battery, and the need for the development of new experimental methods that simulate human memory disorders.