uni'wissen 01-2016_ENG

measures the brain activity of test subjects in a waking state and under hypnosis. The subjects are confronted with brief film sequences of dental treatment in each of these two states, as well as with sequences showing similar but neutral stimuli, such as a hair dryer. Halsband uses various methods to measure brain activity. In this case the test subjects are pushed into a magnetic resonance imaging ma- chine. With the help of functional magnetic reso- nance imaging (fMRI), Halsband can precisely localize their brain activity. The test subjects are briefly placed under hypnosis, either live via mi- crophone or by means of recordings. “When we confront the test subjects with video clips and sounds from a dental procedure in a waking state, the neurons in the amygdala, the insula, and other anxiety centers light up like crazy,” says the researcher. Under hypnosis, on the other hand, the activity in these areas is much less pronounced. The anxiety circuit in the brain is down-regulated, as it were. Halsband also points out that there is a reduction of neural activity in the hippocampus, an important brain region for memory. As a possible explanation, she notes that many of the phobic patients have traumatic memories of previous trips to the dentist that are reactivated when they are confronted with the short films on dental procedures. The type of hypnosis is also plays a role. “We have determined that an individualized form is helpful,” explains Halsband. This involves having the test subjects choose keywords they associate with relaxation beforehand. For many people, these may be terms like “sun,” “beach,” and “sea,” while others might choose “dog,” “soccer,” or “balcony.” “The important thing during hypnosis is then to use these terms to evoke various sensory impressions,” she explains, because the brain Human brain activity can be measured by means of functional magnetic resonance imaging. Photo: Britt Schilling/Freiburg University Medical Center “We have determined that an individualized form is helpful.” Ulrike Halsband studies the brain activity of people who are afraid of going to the dentist while they watch these film se- quences of dental procedures. In a waking state (left), the activity of the amygdala (in color), one of the brain’s anxiety centers, is much higher than under hypnosis. Source: Ulrike Halsband 26

Seitenübersicht