In Tiny Worm, Unlocking Secrets of the Brain

In an eighth-floor laboratory overlooking the East River, Cornelia I. Bargmann watches two colleagues manipulate a microscopic roundworm. They have trapped it in a tiny groove on a clear plastic chip, with just its nose sticking into a channel. Pheromones — signaling chemicals produced by other worms — are being pumped through the channel, and the researchers have genetically engineered two neurons in the worm’s head to glow bright green if a neuron responds.

These ingenious techniques for exploring a tiny animal’s behavior are the fruit of many years’ work by Dr. Bargmann’s and other labs. Despite the roundworm’s lowliness on the scale of intellectual achievement, the study of its nervous system offers one of the most promising approaches for understanding the human brain, since it uses much the same working parts but is around a million times less complex.