Cover Story 2015, Volume 10 Issue 3
New neurons are constantly added to discrete locations in the adult mammalian brain. One of these areas is the dentate gyrus of the hippocampus, a brain area associated with learning and memory. In the dentate gyrus, neural stem cells generate intermediate progenitor cells (IPCs) that divide and eventually mature into functional neurons. While our knowledge of neural stem cells in the dentate gyrus is steadily growing, not much is known of the behavior and development of IPCs.
In a research article published in this issue (Pages 262-271), Berg et al. examine the fate potential and behavior of individual IPCs in mice. To do this, they make use of a technique called clonal analysis, in which they label a small number of IPCs in the whole dentate gyrus using a newly generate mouse model. They can then trace these cells and examine the fate of individual IPCs at different stages of their development. The authors observe that IPCs rapidly differentiate into neurons and do not give rise to astrocytes or revert back to neural stem cells. They also observe that enriched environment together with running, which is known to increase neurogenesis in the dentate gyrus of mice, results in accelerated development of individual IPCs.
The cover image shows different stages of differentiation of IPCs in the adult mouse dentate gyrus. The top two rows show 1 and 2 day old cells and clearly illustrates the different morphology of IPCs with multiple processes. The third row shows 4 day-old cells, with a mostly bipolar morphology and tangential processes. The two bottom rows show 6 and 15 day old cells, which have now become immature neurons and are developing dendrites at the top and axons starting to grow at the bottom.
Using this technique, future studies will be able to measure the electrical signaling of the immature neurons at different stages of their development with extremely high specificity, and examine how these newborn cells contribute to specific functions in the diseased and healthy brain.
Image made by Daniel Berg.
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