Some images show the insides of individual worms’ heads. Some images, at much higher magnifications, narrow in on individual brain cells of living animals. These long-tailed neurons have been genetically instructed to produce fluorescent material, setting them apart under laser light from their numerous (but here-invisible) neighbour cells.
Each image is a flattened composite of multiple photographs; none represents any real living instant. In some images, movement between instants creates blurs and double-vision. Sometimes, other cells and structures appear by surprise, having absorbed fluorescent matter unintended for them, or by their own fluorescent properties. Read more here.