Common and distinct brain activation to threat and safety signals in Social Phobia

Mentzel, H.J., Miltner, W.H.R., Straube, T. (2005). Common and distinct brain activation to

Threat and safety signals in Social Phobia. Neuropsychobiology, 52, 163-168. doi: 10.

1159/000087987

Retrieved from EbscoHost

Chapter 12 defines a phobia as the fear of a clearly defined object or situation. Social phobia, also called social anxiety disorder (SAD), is an intense fear of social situations causing distress and impaired ability to function in daily life. These fears can be specific or generalized. In this study certain facial expressions are being used to see which ones are more threatening to social phobic patients than others and what areas of the brain are affected by them. The amygdala is believed to play an important role in fear response and the potential of a threat. It also helps to process stimuli that cause arousal or emotion. 18 participants were chosen, 9 who had been diagnosed with social phobia and 9 who did not. They were shown a series of photographs with three different facial expressions, happy, angry and neutral, while receiving a FMRI. After the FMRI they were asked to rate the pictures on a scale of 1 (very unpleasant) to 9 (very arousing). The results showed that when social phobics were shown angry faces both sides of the insula was activated. This did not occur when they were shown happy or neutral faces and control participants did not show this activation to any facial expression. The amygdala was activated in both social phobics and the control group to all three types of expressions, but phobics were more activated in this area than controls. The amygdala was more enhanced in social phobics when shown happy and angry faces. The increased activation of these brain areas is believed to be caused by increased evaluation and attention to the stimulus. The insula responses were only to angry faces and therefore is more involved in processing potential threats and consequences in those with social phobia. The amygdala is used for processing threats as well as signals of safety and acceptance.