Once genetic susceptibility to psychiatric disorders such as schizophrenia or bipolar disorder has been identified and replicated, the variants in question are prime targets for focused neurobiological studies to further elucidate their relevance for the mode of action in the pathway leading up to disease presentation. These studies include gene-expression studies and the development and testing of animal models. Ideally, phenotype and endophenotype studies in humans, e.g. brain imaging, can be parallelized with identical approaches in animals (e.g. brain imaging in animals).