Since the early 1960s, in vivo observations have shown the generation of new neurons from
dividing precursor cells. Nevertheless, these experiments suffered from skepticism,
suggesting that the prevailing labeling method, which incorporates tagged thymidine
analogs, such as [3H]-thymidine or bromodeoxyuridine (BrdU), may not be detecting a
proliferative event, but could rather mark DNA repair in postmitotic neurons. Even today
many scientists outside the field are still skeptical, because the question of specificity for …