modified from Franjic et al. (2022) . Cross-species comparison shows transcriptomic signatures of neurogenesis in the hippocampus of adult mouse, pig, and monkey — but not human. Does the adult brain generate new neurons throughout the lifespan? The prevailing view in most of the 20th century was that no new neurons are born in the mammalian brain once development ceases. A series of studies in the 1960s showed otherwise, but these were ignored until the 1990s . A now-historical paper from 2000