Unravelling the mysteries of brain development: Watch Ann and Yana in their daily lab routine, unravelling the development of interneurons! Little is known about how the enormous variety of interneurons arises and how they integrate into functional circuits. Using methods such as genetic fate mapping, single-cell RNA-sequencing, microscopy and statistics, the goal is to elucidate the factors that drive cellular decision-making during interneuron development. Growing evidence suggests that defects in this process are associated with neuropsychiatric diseases such as epilepsy, autism or schizophrenia. Therefore, studying interneurons and their development is crucial for understanding how the brain operates in both health and disease.