Sprenger and his colleagues—whose previous work examined the placebo effect—another brain–body mystery—believes distraction is just one of many cognitive cases in which the brain modulates pain. He adds that their research is a first step. Much of the pain-response process seen in this study remains unknown: current functional magnetic resonance image technology can focus on either the brain or the spinal cord, but not both, and fine details—such as precisely how naloxone interacts with the nervous system and opioids—are invisible.
The study, however, does provide a candidate mechanism for the brain's inhibition of the pain response, a mechanism that can be measured and further studied, eventually leading to clinical applications such as therapies. Meanwhile, the next time you have a toothache, rather than pop some acetaminophen, consider a brainteaser.