People who have more background than me: What does this have to do with memory and recall of immune responses?

So they infected a mouse, monitored the mouse’s neurons to see which ones are active during inflammation, then waited a while, then hit those neurons again and observed inflammation even though there’s no disease the second time.

If they hit the “same” neurons in a mouse that never had the disease in its lifetime, wouldn’t they observe inflammation without memory? (I don’t think they tried it)