Despite not having eyes and living underground, the roundworm C. elegans can actually ‘see’, suggests a paper online in Nature Neuroscience this week.
Shawn Xu and colleagues discovered that when they focussed light on either the head or tail of worms, the worms moved to avoid light ? for instance, if a flash of light was focused on the head of a worm moving forward, it would stop its forward movement and reverse direction. The authors also identify a group of sensory neurons that were critical for this response.
The authors reveal that light excites these cells by acting on cyclic nucleotide gated ion channels. Vertebrate photoreceptor cells also depend on similar channels, suggesting that light-sensing processes may be conserved in both nematodes and vertebrates.