Animal models: An overview

Abstract

Animal studies are indispensable to examine the organization, structure, and function of specific organs and their integrative functions, including those of the cerebellum. Animal studies are classified into several categories. One involves clarifying the mechanisms inducing specific anatomical, physiological, or behavioral phenotypes (phenotype-oriented). Another involves analyzing the effects of specific endogenous molecules/genes/proteins on cellular, organ, and/or behavioral functions (molecule-oriented). Animal studies are also applied to examine the effect of exogenous chemicals (xenobiotics) such as pharmaceuticals, cosmetics, and industrial and environmental chemicals. In addition, animal models mimicking human disease are also used for better understanding the pathophysiological aspects of disease. Recent developments in molecular biology have enabled us to generate a large number of gene-modified animals for such purposes. Such animal models have contributed greatly to understanding further the gene-phenotype or gene-disease interactions. On the other hand, it is needless to say that multiple substances are involved in generating morphological, physiological, and behavioral phenotypes. Furthermore, many neurological disorders are induced by polygenic abnormalities. Thus, examining naturally occurring mutant animals and injury- or drug-induced animal models is still very important. It is almost impossible, however, to discuss all animal models for cerebellar research, including gene-modified animals. Thus, in this chapter, representative naturally occurring mutant animal models that are used to study cerebellar function and diseases are mainly introduced. Before the detailed description of each animal model, a general overview and classification of the animal models used for cerebellar research is given.