Placebo gives brain emotional break

The placebo effect, in which people experience health benefits from inactive medications, thrives on great expectations. According to a new study of placebo-induced reduction of anxiety, such expectations trigger a decline in the brain’s emotional responsiveness and marshal pain-numbing neural activity.

A team led by Predrag Petrovic of the Karolinska Institute in Stockholm tested 15 women over 2 days. On the first day, each volunteer used a scale of 1 to 100 to rate the unpleasantness of pictures presented to her.