Brent A. Reynolds, whose work profoundly reshaped our understanding of the adult brain’s capacity for regeneration, passed away on April 11, 2026, at the age of 63. In 1992, working with Samuel Weiss, Reynolds reported the existence of neural stem cells in the adult mammalian brain, providing a compelling demonstration that the adult central nervous system retains the capacity to generate new neurons. This work challenged long-standing assumptions and opened new directions in the study of brain plasticity and repair.