Since completion of the genome sequencing of a variety of organisms including the mouse and human being, it has become our big task to elucidate the functions of the sequenced genomes. For this purpose, biomedical researchers inactivate particular genes of their interest in the mouse and analyze the phenotypes of the mutated animals, thereby revealing the physiological functions of the inactivated genes. We will devote our efforts to the investigation on the higher cognitive functions in the immune and nervous systems of the mouse and human being.