Do you mean something like this (from the article)?
"Three years later, a Swedish-American team, led by Peter Eriksson of Sahlgrenska University Hospital, published a study in Nature that showed, for the very first time, that neurogenesis – the creation of new brain cells – was possible in adults. In 2006, a team led by Eleanor Maguire at the Institute of Neurology at University College London found that the city’s taxi drivers have more grey matter in one hippocampal area than bus drivers, due to their incredible spatial knowledge of London’s maze of streets."
Also, as of at least 2013, people were still publishing papers skeptical that neurogenesis is being measured here:
>"In the adult cortex, one point of consensus is that the numbers of adult-born neurons are low and their lives are short. Thus, we need to search for them, like needles in a haystack, perhaps in many “haystacks” subject to different conditions. In addition, supplemental approaches need to be developed since BrdU may label neurons repairing their DNA; alternatively, markers of DNA repair need to be routinely performed. Due to their low number, it is difficult to conclude whether the identified BrdU/NeuN+ cells are the result of progenitor proliferation or neuronal repair."
"Three years later, a Swedish-American team, led by Peter Eriksson of Sahlgrenska University Hospital, published a study in Nature that showed, for the very first time, that neurogenesis – the creation of new brain cells – was possible in adults. In 2006, a team led by Eleanor Maguire at the Institute of Neurology at University College London found that the city’s taxi drivers have more grey matter in one hippocampal area than bus drivers, due to their incredible spatial knowledge of London’s maze of streets."