The brain contains diverse cell types, including different types of neurons such as dopaminergic and serotonergic neurons, which interact to regulate brain function. This project aims to develop viral vector technology for cell type-specific gene expression in experimental animals. We will establish methods to selectively express functional genes that enable morphological analysis of cells and measurement/control of neural activity in wild-type animals. This will contribute to a detailed understanding of brain function and its alterations in disease models.