The early stage of processing emotional faces in patients with major depressive disorder: an event-related potential study

Subjectively salient faces differ from emotional faces: ERP evidence

The self-face is processed differently than emotional faces. A question arises whether other highly familiar and subjectively significant non-self faces (e.g. partner's face) are also differentiated from emotional faces. The aim of this event-related potential (ERP) study was to investigate the neural correlates of personally-relevant faces (the self and a close-other's) as well as emotionally positive (happy) and neutral faces. Participants were tasked with the simple detection of faces. Amplitudes of N170 were more negative in the right than in the left hemisphere and were not modulated by type of face. A similar pattern of N2 and P3 results for the self-face and close-other's face was observed: they were associated with decreased N2 and increased P3 relative to happy and neutral faces. However, the self-face was preferentially processed also when compared to a close-other's face as revealed by lower N2 and higher P3 amplitudes. Nonparametric cluster-based permutation tests showed an analogous pattern of results: significant clusters for the self-face compared with all other faces (close-other's, happy, neutral) and for close-other's face compared to happy and neutral faces. In summary, the self-face prioritization was observed, as indicated by significant differences between one's own face and all other faces. Crucially, both types of personally-relevant faces differed from happy faces. These findings point to the pivotal role of subjective evaluation of the saliency factor.

Decreased hemodynamic response to fearful faces relative to neutral faces in the medial frontal cortex of first-episode drug-naïve major depressive disorder

BACKGROUND

Major depressive disorder (MDD) is a disabling disease with impaired recognition of emotional facial expressions. However, the evidence is heterogeneous, regarding the mechanism of emotional processing in MDD. Focusing on patients with first-episode drug-naïve MDD, we used functional near-infrared spectroscopy (fNIRS) to investigate whether MDD have characteristic patterns in cerebral activation under facial emotion recognition task (FERT).

METHODS

Thirty-five patients with first-episode drug-naïve MDD and 39 healthy controls (HCs) underwent fNIRS measure to evaluate cerebral hemodynamic response in the frontal and temporal cortex during FERT. The 17-item Hamilton Depression Rating Scale, Hamilton Anxiety Rating Scale and Inventory of Depressive Symptomatology-Self Report were applied to assess the symptoms of the patients. Cognitive functions were assessed using THINC-integrated tool.

RESULTS

Hypoactivation in the medial frontal was observed in patients with MDD during recognition of fearful faces relative to neutral faces (F-N faces). Specifically, we found more right lateralized activation in the medial frontal cortex among patients with MDD compared to HCs. Further, the medial frontal activation under the condition of F-N faces was positively correlated to scores of digit symbol substitution test, and negatively relative to severity of depressive symptoms in MDD group.

LIMITATIONS

Our study is cross-sectional designed, and has a relatively small sample size.

CONCLUSIONS

We found abnormal patterns in the medial frontal activation of patients with first-episode drug-naïve MDD in recognition of F-N faces, which correlates with performance in cognitive function and depressive symptoms.

The Processing of Visual Signals in Major Depressive Disorder

The balanced processing of the internal mental world and the external world is a crucial aspect of everyday well-being. An extensive control of the internal emotional and cognitive world that often results in an internal expression of distress is a common feature of internalizing disorders. However, how depression affects the processing of the external world is still an open question. We, therefore, tested the processing of visual signals in major depressive disorder (MDD). To this end, we recorded the electroencephalogram of 38 MDD patients and 38 controls, while they performed a response-choice task with informative feedback and a passive viewing task. MDD patients differed significantly from controls in the early information processing of visual stimuli. The vertex positive potential (VPP) evoked by feedback in the response-choice task and pictures in the passive viewing task were smaller in MDD patients than in controls. This outcome suggests that depression might subtract attentional resources from external signal processing, with potential consequences in various cognitive domains.