Beyond emotions: A meta-analysis of neural response within face processing system in social anxiety

Major depression disorder (MDD) and anxiety disorder are both prevalent and debilitating. High rates of comorbidity between MDD and social anxiety disorder (SAD) suggest common pathological pathways, including aberrant neural processing of interpersonal signals. In patient populations, the determination of common and distinct neurofunctional markers of MDD and SAD is often hampered by confounding factors, such as generally elevated anxiety levels and disorder-specific brain structural alterations. This study employed a dimensional disorder approach to map neurofunctional markers associated with levels of depression and social anxiety symptoms in a cohort of 91 healthy subjects using an emotional face processing paradigm. Examining linear associations between levels of depression and social anxiety, while controlling for trait anxiety revealed that both were associated with exaggerated dorsal striatal reactivity to fearful and sad expression faces respectively. Exploratory analysis revealed that depression scores were positively correlated with dorsal striatal functional connectivity during processing of fearful faces, whereas those of social anxiety showed a negative association during processing of sad faces. No linear relationships between levels of depression and social anxiety were observed during a facial-identity matching task or with brain structure. Together, the present findings indicate that dorsal striatal neurofunctional alterations might underlie aberrant interpersonal processing associated with both increased levels of depression and social anxiety.

Anxiety disorders are the most common mental health disorders, and daily transient feelings of anxiety (or "stress") are ubiquitous. However, the precise impact of both transient and pathological anxiety on higher-order cognitive functions, including short-and long-term memory, is poorly understood. A clearer understanding of the anxiety-memory relationship is important as one of the core symptoms of anxiety, most prominently in post-traumatic stress disorder (PTSD), is intrusive reexperiencing of traumatic events in the form of vivid memories. This study therefore aimed to examine the impact of induced anxiety (threat of shock) on memory encoding and retrieval. Eighty-six healthy participants completed tasks assessing: visuospatial working memory, verbal recognition, face recognition, and associative memory. Critically, anxiety was manipulated within-subjects: information was both encoded and retrieved under threat of shock and safe (no shock) conditions. Results revealed that visuospatial working memory was enhanced when information was encoded and subsequently retrieved under threat, and that threat impaired the encoding of faces regardless of the condition in which it was retrieved. Episodic memory and verbal short-term recognition were, however, unimpaired. These findings indicate that transient anxiety in healthy individuals has domain-specific, rather than domain-general, impacts on memory. Future studies would benefit from expanding these findings into anxiety disorder patients to delineate the differences between adaptive and maladaptive responding.

The late positive potential (LPP) and fMRI blood-oxygen-level dependent (BOLD) activity can provide complementary measures of the processing of affective and social stimuli. Separate lines of research using these measures have often employed the same stimuli, paradigms, and samples; however, there remains relatively little understanding of the way in which individual differences in one of these measures relates to the other, and all prior research has been conducted in psychiatrically healthy samples and using emotional scenes (not faces). Here, 32 combat-exposed U. S. military veterans with varying levels of posttraumatic stress symptomatology viewed affective social stimuli (angry, fearful, and happy faces) and geometric shapes during separate EEG and fMRI BOLD recordings. Temporospatial principal component analysis was used to quantify the face-elicited LPP in a data-driven manner, prior to conducting whole-brain correlations between resulting positivities and fMRI BOLD elicited by faces. Participants with larger positivities to fearful faces (> shapes) showed increased activation in the amygdala; larger positivities to angry and happy faces (> shapes) were associated with increased BOLD activation in the posterior fusiform gyrus and inferior temporal gyrus, respectively. Across all face types, larger positivities were associated with increased activation in the fusiform "face" area. Correlations using mean area amplitude LPPs showed an association with increased activation in the anterior insula for angry faces (> shapes). LPP-BOLD associations were not moderated by PTSD. Findings provide the first evidence of correspondence between face-elicited LPP and BOLD activation across a range of (normal to disordered) psychiatric health.