Functional brain connectivity during fear of pain: a comparison between dental phobics and controls

Fear of pain is the most common reason for avoiding the dentist by patients suffering from dental phobia. Previous functional magnetic resonance imaging investigations demonstrated that already thinking about pain during the viewing of images depicting dental treatment provoked enhanced orbitofrontal cortex (OFC) activation in the clinical group. In the present study, the authors investigated whether this differential activation can be explained by differential connectivity patterns between patients and controls. They found that the control subjects displayed a stronger and more widespread connectivity compared to patients. This connectivity pattern comprised prefrontal seeds (e.g., the anterior cingulate cortex), which were coupled with limbic structures (e.g., the amygdala) and the basal ganglia (putamen, pallidum, caudate nucleus). This pattern might reflect successful emotion regulation, which was absent in the clinical group. The patients showed coupling of the OFC and the caudate nucleus, which may be the neural correlate of associating pain with dental treatment.