Yesterday I was taking pictures of 1-day-old neurons, which was irritating me for several reasons. First, at this age they’re small, irregular and uglier than the mature neurons I’m used to examining. Second, very immature neurons are located amongst a mess of proliferating cells and fellow young neurons so it becomes hard to discern one cell from the next.
One positive thing that came out of looking at these very immature neurons was that I got the chance to see several examples of pyknotic (dying) cells. Older, adult-born neurons also die, particularly after an experience (see here and here), but it’s infrequent and hard to visualize. However, a relatively large proportion of new neurons die within a few days of their birth making them easier to find – the cluster of cells shown below is an example that caught my attention.