The discoveries that neurons that mediate birdsong in canaries are replaced by new neurons produced from stem cells, and that this turnover of the neurons is regulated by testosterone in a seasonal manner, have provided important insight into the control of neurogenesis by environmental factors. In their new study, Alvarez-Borda et al. provide evidence that BDNF promotes the survival of newly generated neurons in the high vocal center of the canaries. Remarkably, there is only a very tight time window of approximately two weeks following neurogenesis in the spring when BDNF is capable of promoting the long-term survival of the newly generated neurons. These findings have important implications for the regulation of adult neurogenesis in mammals as well as for the importance of neurogenesis in learning and memory processes.
Recent studies of neurogenesis in the hippocampus and forebrain of mice
suggest that the continued production of new neurons is required for at
least some aspects of learning and memory [1,2]. Presumably, newly
generated neurons must integrate into neuronal...