Altered coordination between frontal delta and parietal alpha networks underlies anhedonia and depressive rumination in major depressive disorder.

BACKGROUND: A hyperactive default mode network (DMN) has been observed in people with major depressive disorder (MDD), and weak DMN suppression has been linked to depressive symptoms. However, whether dysregulation of the DMN contributes to blunted positive emotional experience in people with MDD is unclear. METHODS: We recorded 128-channel electroencephalograms (EEGs) from 24 participants with MDD and 31 healthy controls in a resting state (RS) and an emotion-induction state (ES), in which participants engaged with emotionally positive pictures. We combined Granger causality analysis and data-driven decomposition to extract latent brain networks shared among states and groups, and we further evaluated their interactions across individuals. RESULTS: We extracted 2 subnetworks. Subnetwork 1 represented a delta (δ)-band (1~4 Hz) frontal network that was activated more in the ES than the RS (i.e., task-positive). Subnetwork 2 represented an alpha (α)-band (8~13 Hz) parietal network that was suppressed more in the ES than the RS (i.e., task-negative). These subnetworks were anticorrelated in both the healthy control and MDD groups, but with different sensitivities: for participants with MDD to achieve the same level of task-positive (subnetwork 1) activation as healthy controls, more suppression of task-negative (subnetwork 2) activation was necessary. Furthermore, the anticorrelation strength in participants with MDD correlated with the severity of 2 core MDD symptoms: anhedonia and rumination. LIMITATIONS: The sample size was small. CONCLUSION: Our findings revealed altered coordination between 2 functional networks in MDD and suggest that weak suppression of the task-negative α-band parietal network contributes to blunted positive emotional responses in adults with depression. The subnetworks identified here could be used for diagnosis or targeted for treatment in the future.

Individual differences in emotion prediction and implications for social success.

The social world requires people to predict others' thoughts, feelings, and actions. People who successfully predict others' emotions experience significant social advantages. What makes a person good at predicting emotions? To predict others' future emotional states, a person must know how one emotion transitions to the next. People learn how emotions transition from at least two sources: (a) internal information, or one's own emotion experiences, and (b) external information, such as the social cues detected in a person's face. Across five studies collected between 2018 and 2020, we find evidence that both sources of information are related to accurate emotion prediction: individuals with atypical personal emotion transitions, difficulty understanding their own emotional experiences, and impaired emotion perception displayed impaired emotion prediction. This ability to predict others' emotions has real-world social implications. Individuals who make accurate emotion predictions have better relationships with their friends and communities and experience less loneliness. In contrast, disruptions in both internal and external information sources explain prediction inaccuracy in individuals with social difficulties, specifically with social communication difficulties common in autism spectrum disorder. These findings provide evidence that successful emotion prediction, which relies on the perception of accurate internal and external data about how emotions transition, may be key to social success. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Mask exposure during COVID-19 changes emotional face processing.

Faces are one of the key ways that we obtain social information about others. They allow people to identify individuals, understand conversational cues, and make judgements about others' mental states. When the COVID-19 pandemic hit the United States, widespread mask-wearing practices were implemented, causing a shift in the way Americans typically interact. This introduction of masks into social exchanges posed a potential challenge-how would people make these important inferences about others when a large source of information was no longer available? We conducted two studies that investigated the impact of mask exposure on emotion perception. In particular, we measured how participants used facial landmarks (visual cues) and the expressed valence and arousal (affective cues), to make similarity judgements about pairs of emotion faces. Study 1 found that in August 2020, participants with higher levels of mask exposure used cues from the eyes to a greater extent when judging emotion similarity than participants with less mask exposure. Study 2 measured participants' emotion perception in both April and September 2020 -before and after widespread mask adoption-in the same group of participants to examine changes in the use of facial cues over time. Results revealed an overall increase in the use of visual cues from April to September. Further, as mask exposure increased, people with the most social interaction showed the largest increase in the use of visual facial cues. These results provide evidence that a shift has occurred in how people process faces such that the more people are interacting with others that are wearing masks, the more they have learned to focus on visual cues from the eye area of the face.

Reduced adaptation of glutamatergic stress response is associated with pessimistic expectations in depression.

Stress is a significant risk factor for the development of major depressive disorder (MDD), yet the underlying mechanisms remain unclear. Preclinically, adaptive and maladaptive stress-induced changes in glutamatergic function have been observed in the medial prefrontal cortex (mPFC). Here, we examine stress-induced changes in human mPFC glutamate using magnetic resonance spectroscopy (MRS) in two healthy control samples and a third sample of unmedicated participants with MDD who completed the Maastricht acute stress task, and one sample of healthy control participants who completed a no-stress control manipulation. In healthy controls, we find that the magnitude of mPFC glutamate response to the acute stressor decreases as individual levels of perceived stress increase. This adaptative glutamate response is absent in individuals with MDD and is associated with pessimistic expectations during a 1-month follow-up period. Together, this work shows evidence for glutamatergic adaptation to stress that is significantly disrupted in MDD.

An ERP study of multidimensional source retrieval in depression.

We collected event-related potentials (ERPs) from 24 unmedicated adults with Major Depressive Disorder (MDD) and 24 controls during source memory retrieval. Words were encoded on the left or right during animacy and mobility judgments. Mobility judgments were slower than animacy judgments, suggesting deeper encoding. Participants then recalled the encoding judgment (Question cue) and position (Side cue) for each word. Depressed adults, but not controls, showed better accuracy for words from the mobility task presented under the Question vs. Side Cue. Furthermore, depressed adults showed larger left parietal ERPs to words from the mobility task presented under the Question vs. the Side Cue from 400 to 800 ms and 800-1400 ms. This ERP effect was negatively correlated with sleep quality. Thus, deep encoding followed by retrieval of the encoding judgment supported memory in MDD and augmented left parietal ERPs that have been linked to recollection and that appear sensitive to sleep disturbance.