Although placebos may only be sham medicines, the benefits patients believe they receive appear to be more than illusions. Neuroscientists at the Universities of Michigan at Ann Arbor and Maryland injected saltwater into the jaw muscles of healthy young male volunteers to cause pain. The researchers then told them that intravenous saline drips might be painkillers and asked them to rate the intensity of their discomfort on a scale of 0 to 100 every 15 seconds. Brain scans revealed that neural areas linked with responses to pain, stress, rewards and emotion released endorphins, natural analgesics that behave like opiates. The endorphin response matched up in time with reductions in pain intensity and unpleasantness the volunteers reported. The scientists, whose findings appear in the August 24 Journal of Neuroscience, plan on researching this effect in women and in patients with chronic pain.