WE SAY something is “rocket science” when it is stunningly complex. But perhaps “neuroscience” would be a more apt metaphor—the more we learn about the brain, the more new questions arise. Case in point is a seemingly simple question: How do brain cells communicate? We know they use chemicals to send messages to one another. But exactly how do neurons release these neurotransmitters and then ready themselves to send out another rapid-fire message?
This operation takes place on a vanishingly small scale—scientists cannot actually watch the process, so they have to rely on less direct measures to determine what is going on. And because such data can often be interpreted in multiple ways, a controversy about neurotransmitter release has persisted for decades. Recent advances in laboratory techniques have escalated the debate, and the promise of finally understanding this basic cellular mechanism has set the stakes high. The answer is vital because the chemicals in our brain are implicated in everything from thought and emotion to mental illness, addiction and disease.