The age of olfactory bulb neurons in humans.
Continuous turnover of neurons in the olfactory bulb is implicated in several key aspects of olfaction. There is a dramatic decline postnatally in the number of migratory neuroblasts en route to the olfactory bulb in humans, and it has been unclear to what extent the small number of neuroblasts at later stages contributes new neurons to the olfactory bulb. We have assessed the age of olfactory bulb neurons in humans by measuring the levels of nuclear bomb test-derived (14)C in genomic DNA. We report that (14)C concentrations correspond to the atmospheric levels at the time of birth of the individuals, establishing that there is very limited, if any, postnatal neurogenesis in the human olfactory bulb. This identifies a fundamental difference in the plasticity of the human brain compared to other mammals.
Department of Cell and Molecular Biology, Karolinska Institute, SE-17177 Stockholm, Sweden.
Olaf
O
Bergmann
Jakob
J
Liebl
Samuel
S
Bernard
Kanar
K
Alkass
Maggie S Y
MS
Yeung
Peter
P
Steier
Walter
W
Kutschera
Lars
L
Johnson
Mikael
M
Landén
Henrik
H
Druid
Kirsty L
KL
Spalding
Jonas
J
Frisén
D002465:Cell Movement / Q000502:physiology; D006801:Humans; D055495:Neurogenesis / Q000502:physiology*; D009474:Neurons / Q000166:cytology* / Q000502:physiology; D009830:Olfactory Bulb / Q000166:cytology* / Q000502:physiology; D012903:Smell / Q000502:physiology*