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Our study of the surprisingly prolonged development of adult-born hippocampal neurons now out in J Neurosci. https://www.jneurosci.org/content/early/2020/06/22/JNEUROSCI.1665-19.2020
Since neurogenesis declines with age, and is controversial in adult humans, we asked whether extended development might provide a source of plasticity even when few cells are being born on a daily basis.
Answer: it did. Adult-born neurons grew more spines, larger presynaptic terminals, longer dendrites from 2-6 months of cell age. This is ~25% of the rat lifespan!
It is often stated, without substantiation, that adult ng contributes few cells. But using published numbers we estimated that, ultimately, ~50% of cells are added in adulthood*.
*though fewer functionally unique cells can also have a big impact, as @jbimaknee would remind us
*though fewer functionally unique cells can also have a big impact, as @jbimaknee would remind us
Combined with extended dendrite growth (ultimately 4 km!) and spine formation (7+ billion), adult neurogenesis contributes structural plasticity to the hippocampus until the end of life (even in a model where cell birth ends at mid life, which is likely a premature estimate).
2nd major finding is that *old* adult-born neurons have mo spines and larger terminals than neonatal-born neurons. We think these may be the spine-rich (~2x) dentate neurons that have been described in human & animal golgi samples. Check out these dendritic cannons in 7w cells!
DVD extra: video of dendritic trifurcation. Not specific to adult-born cells, but previously undescribed in dentate (hippocampus?) as far as we could tell.
This beautiful, detailed and descriptive study was led by @DelaneEspinueva and JD Cole, with critical contributions from @DesireeSeib, @alyssaaash, @MattCooke14, @shainacahill.
