The Multiple Resilience of a Nervous Stem

Long lived animals like humans don't start seeing degraded function until as late as you do. This is a consequence of the fact that you can't specify every single cell in your brain, which gives rise to this differential resilience. So those are the kinds of problems that we've been studying these years. And having a nervous stem which is easy to record from and easy to manipulate makes it easier to ask some of these questions than if you had a complicated human nervous system.