I have done some work with the C. Elegans model organism. They are fun little bugs, and the PETA doesn’t get all up-in-arms when you shoot their brain with a laser. Here are some fun C. Elegans Facts:
They are about 1 mm long at maturity
They are transparent
They have about 300 nerves
Their genome was sequenced in 1998
They can hunt down food on a plate
They have forms of memory and learning
Here are some things I have noticed: When illuminated with a blue laser, they panic and squirm all over the place. When you use a UV laser to blow up a portion of their outer cuitcle, they practically turn inside-out due to internal pressure. Some of the strains available through the WormBank have single nerve cells that express fluorescent protein, so that not only do their brains glow, but only the part you might be interested in glows.
Why are these critters cool? Well, despite being really small, they share a lot of biochemistry with humans. Their neurons function in the same way and the cellular processes that allow the worm to grow from an egg into a larva and from a larva into an adult are all analogous on a cellular level to changes in human development. But if you do an experiment on a worm, you can see what happens in a few days instead of months (rats) years (monkeys) or decades (humans). Also, there are some ethical constraints with humans that don’t apply to worms.
Here’s a new fact just released in Nature: they seem to have a sleep-like state. “Lethargus is a Caenorhabditis elegans sleep-like state” by Raizen et. al. “Conserved effects on sleep-like behaviour of homologous genes in C. elegans and Drosophila suggest a common genetic regulation of sleep-like states in arthropods and nematodes. Our results indicate that C. elegans is a suitable model system for the study of sleep regulation.”
They sleep, they eat, they learn (sort-of), they have lots of sex with themselves (they are hermaphrodites) and they make eggs. And they do it all in 3 days. And despite the fact that we know the fate of every cell in its body from birth to death – where it comes from, what it becomes and where it goes – we still don’t know how it manages most of its behavior.
I’d like to point out that this leaves very little hope for a reductionist perspective on psychology. We know every connection of every nerve in this worm’s body and the thing is still a mystery. I wrote a post recently about how foolish it is to make sweeping assertions about genetic differences. Just to reiterate the big upshot: even in the simplest case, our understanding of the causes-and-effects that make up psychology is limited. To think that a human being is perfectly predictable is… well… just plain dumb.