This is a confocal miscroscopy image of the nerve ring, or head ganglia- “brain” structure, from C. elegans. Even though the term “brain” is used loosely in these tiny worms, this nerve ring does receive some sensory input and output some motor information, though nothing near as complex as the way our brain does. Let’s also remember the whole worm is less than 1 mm in total length, so imagine how tiny this nerve ring is! It’s quite amazing, I think, that we are able to see it- and with such resolution. For more information about C. elegans and why would study them, see this post.