That's a great one! Space photos are all so beautiful, and always remind me of how small we really are. Here's one of my favorites, a colorful stain of the dentate gyrus of the hippocampus: Also, Ramón y Cajal had madr such beautiful drawings of neurons, here's one of my favorites! (Edit, I just noticed you have a separate illustrations thread, sorry for posting an illustration here!)
It's a method of genetic engineering that causes neurons to express different ratios of three fluorescent proteins. The neurons thus end up randomly colored and more easily distinguishable / trackable from each other. It's a pretty neat trick used in the field of developmental biology and brain connectomics to track cell fate / neuronal connections.
I can't even fathom drawing out all those little neurons and their parts in such detail. Just looking in the microscope for that long and trying to see that much detail would be exhausting. The hippocampus picture is equally amazing and to think that's just a tiny part of all the neurons in our brain and with so many connections too!
Yeah, it's crazy. Ramón y Cajal was not only a fantastic scientist - he introduced one of the most fundamental principles of neuroscience - he also made hundreds of such detailed drawings. It's crazy to think of the amount of devotion he poured into his work.