These are not results, rather they are only the very beginning of figuring out how to get results. But they’re promising and pretty.
What I am trying to image, is the longitudinal extension of sensory afferents in the neural tube. The cell bodies of these axons live in little clumps all up and down either side of the spinal cord, and they project towards the mid-line (eventually into the grey matter of the cord itself) and towards the periphery (so you can detect sensations like pain, temperature and pressure). In the embryo, chicken, these cells develop in the ganglia and then grow into the cord. But before they grow in, they grow rostrally (north) and caudally (south) in neural tube. How this growth progresses normally, and what effect inhibited or enhanced cAMP (part of cellular messaging systems) has on the growth – these are the things I am trying to understand and visualize.
With that in mind, the little branches at the bottom are what interest me. The big blobs at the top are the dorsal root ganglia, painstakingly labeled with DiI in live tissue, and then preserved. The extensions out of the blobs are the dorsal roots extending into the neural tube, and the branching at the bottom appears to be the longitudinal extension of these axons within the neural tube.
So, the theory goes, if I can get these pictures, I can get better pictures, live pictures (skipping the preservation step), and eventually sort of a movie of the growth in real time using that fancy microscope. Right now, it seems like it is not an impossibility; and in truth, I am looking forward to giving it a shot.
Here is my favorite. The clearest globe-like ganglion with it’s little roots and longitudinal extensions just streaming out, reaching for those other segments. Enjoy!