Thinking like a worm

There’s a fascinating article in the New York Times about a scientist who can think like a worm. Dr. Cornelia I. Bargmann studies the brain of the roundworm, C. elegans. Yes, worms only a millimeter long have brains. Science has yet to establish the existence of zombies to eat them.

This animal is so small, you can count up the cells in its body (959) and its neurons (302) and even the neurons for smell (32). If you think that makes it simple, you’d be wrong, and you’d be in distinguished company. One scientist spent years charting how exactly those neurons are connected, and another charting how exactly each cell develops from an egg.  Its genome turned out to have about 22,000 genes, almost as many as humans. But knowing the exact structure of a worm doesn’t tell you how it lives, any more than dissecting a corpse would tell you why a congressman would take a photo of his underwear.

Since you can’t interrogate a worm’s brain at a press conference, Dr. Bargmann studies its functions by turning neurons off, one by one, and observing what stops working. This sounds tedious, but I get the feeling that for her it’s more like tweaking a cookie recipe to get exactly the right balance of chocolate chips and pecans. And once you have it figured out, you can do cool stuff like connect the neuron that says “Mmm, buttery!” to the one that says, “Eww, gross!” and create an organism that runs away from movie theater popcorn.

Just like C. elegans, we sense things and react to them. We have some of the same genes. Our common heritage makes it possible to imagine what it would be like to live as a tiny animal in a sensory world that consisted entirely of taste and smell. Thinking like a worm is impressive, but so are many of the other purposes to which we apply the billions of neurons and trillions of connections in our brains. We can only hope that someday research like this will help more people think like human beings.

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