The hippocampus is a brain region that harbors neural stem cells with the remarkable ability to generate new neurons throughout life. Our research focuses on unraveling the cellular and molecular mechanisms that govern the transformation of these stem cells into neurons, as well as the processes that regulate neuronal growth, integration into local circuits, and the selection of synaptic partners. We also explore key characteristics of adult-born neurons, examining how they contribute to learning and behavior. Our team has discovered that the aging brain retains the capacity to incorporate new neurons in a manner that is greatly enhanced when brain circuits are activated by specific stimuli. Currently, we are delving into the precise molecular pathways that control the growth, integration, and survival of new neurons in the adult, aging, and diseased brain. In addition, we analyze hippocampal biopsies from epileptic patients to assess the presence and functionality of immature neurons (potential adult-born cells) in humans, further investigating their properties and role in brain function.