24 Jul How do placebos ease pain? Mouse brain study offers clues

By Miryam Naddaf , Nature

When people take a sugar pill they believe is a painkiller, it can lessen their experience of pain.

Researchers have long known about this phenomenon, called the placebo effect. But the biological mechanisms behind it have remained a mystery. Now, neuroscientists have identified brain circuits in mice that could help to explain how placebos can relieve pain.

In a study published today in Nature, scientists traced the parts of the brain that were activated in mice conditioned to expect pain relief, mimicking how humans experience the placebo effect when given a pill with no active ingredients. They were surprised to see activity in the cerebellum and brainstem — parts of the brain that are typically associated with movement and coordination, rather than pain perception. Read more…