The role of stem cells in the nervous system has become increasingly apparent. The brain is the most complex organ in the body and comprises a highly complex array of neurons and glia. During development, neural stem cells divide to generate all the cells in the brain. While most nerve cells are generated during embryogenesis and do not renew or regenerate in disease or injury, neural stem cells persist in specialized niches in the adult mammalian brain. These adult stem cells continuously give rise to particular subtypes of neurons that integrate into restricted brain regions throughout life. Adult neurogenesis may represent a novel form of plasticity involved in memory formation as well as in mood disorders, such as depression. CSCI researchers aim to better understand the biology and role of endogenous neural stem cells during development and in the adult, as well as the regulatory networks controlling their differentiation into neurons and glia. They are also studying the specialized niche that supports the lifelong self-renewal of neural stem cells. Such approaches will yield important insights into brain development and function, in particular to help us better understand psychiatric disorders and cancer and serve as the basis for new strategies for brain repair.