Beyond amygdala: Default Mode Network activity differs between patients with social phobia and healthy controls

The Default Mode Network (DMN) is a constellation of brain areas that decrease their activity during a wide number of different goal-oriented tasks as compared to passive "rest" tasks. DMN can be modulated by different factors such as emotional states, cognitive load of the task and psychopathology, including anxiety. Moreover, DMN seems to play a pivotal role in social cognition. For example, the ability to predict another person's behaviour taking his or her perspective modulates the activity of the DMN. Recent data from autistic patients support a role of DMN in social cognition as well. Social Phobia (SP) is an anxiety disorder characterized by an abnormal distress in situations that require social interaction. To date, no study has assessed DMN in Social Phobia. To determine potential differences in DMN activity between Social Phobia patients (SPP) and healthy control (HC) subjects we examined functional magnetic resonance imaging (fMRI) data obtained during a face perception study with emotional and neutral stimuli. As compared to HC, SPP showed a lower deactivation in the precuneus and posterior cingulate regions (PCun/PCC) during task conditions. These regions are part of the so-called "Theory of Mind" circuit and in particular they are involved in the evaluation of one's own emotional state. Because of the role of the PCun/PCC in self-state perception and attribution and, more in general, the role of the DMN in social cognition, we suggest that its impairment in the DMN network in SPP might be relevant in the development of the feeling of wariness of others' judgment and may be related to the so-called self-focused attention. Self-focused attention is the awareness of self-referent information, and is present in many emotional disorders and may additionally prevent individuals from observing external information that could disconfirm their own fears. Moreover, the abnormal modulation of activity in the DMN may reflect persistent rumination or anxiety-related thoughts that are not modulated by the switch from rest to task.