Neural Basis of the Emotional Conflict Processing in Major Depression: ERPs and Source Localization Analysis on the N450 and P300 Components.
ABSTRACT: Objects: Effective psychological function requires that cognition is not affected by task-irrelevant emotional stimuli in emotional conflict. Depression is mainly characterized as an emotional disorder. The object of this study is to reveal the behavioral and electrophysiological signature of emotional conflict processing in major depressive disorder (MDD) using event-related potentials (ERPs) and standardized low-resolution brain electromagnetic tomography (sLORETA) analysis. Method: We used a face-word Stroop task involving emotional faces while recording EEG (electroencephalography) in 20 patients with MDD and 20 healthy controls (HCs). And then ERPs were extracted and the corresponding brain sources were reconstructed using sLORETA. Results: Behaviorally, subjects with MDDs manifested significantly increased Stroop effect when examining the RT difference between happy incongruent trials and happy congruent trials, compared with HC subjects. ERP results exhibited that MDDs were characterized by the attenuated difference between P300 amplitude to sad congruent stimuli and sad incongruent stimuli, as electrophysiological evidence of impaired conflict processing in subjects with MDD. The sLORETA results showed that MDD patients had a higher current density in rostral anterior cingulate cortex (rostral ACC) within N450 time window in response to happy incongruent trials than happy congruent stimuli. Moreover, HC subjects had stronger activity in right inferior frontal gyrus (rIFG) region in response to incongruent stimuli than congruent stimuli, revealing successful inhibition of emotional distraction in HCs, which was absent in MDDs. Conclusion: Our results indicated that rostral ACC was implicated in the processing of negative emotional distraction in MDDs, as well as impaired inhibition of task-irrelevant emotional stimuli, relative to HCs. This work furnishes novel behavioral and neurophysiological evidence that are closely related to emotional conflict among MDD patients.
Project description:To investigate the emotional conflict processing during the processing of emotional stimuli in individuals with different levels of social adjustment through developing an event-related potential (ERP) method, the study used positive words (happy), negative words (disgusted), positive faces and negative faces as experimental materials for a face-word Stroop emotional conflict task, which was completed by 34 participants. For the N2 component, there was a significant difference between the high and low social adjustment groups for the congruent condition; the low social adjustment group evoked more negative amplitude under the congruent condition. Under the incongruent condition, there was a marginally significant difference between the high and low social adjustment groups; the low social adjustment group evoked more negative amplitude under the incongruent condition. For the SP component, there were no significant differences for both the high and low social adjustment group between the congruent and incongruent conditions of emotional conflict. However, within the low social adjustment group, the incongruent evoked more positive amplitude. Our findings indicate that the difference in the emotional conflict process between individuals with high and low social adjustment mainly lies in the early processing stages of emotional information. That is, for both congruent and incongruent emotional stimuli, individuals with high social adjustment showed better emotional conflict monitoring, used less cognitive resources, and had a higher degree of automated processing than those with low social adjustment. During the later stages of emotional conflict processing, individuals with low social adjustment showed poorer conflict processing.
Project description:This research investigated the individual behavioral and electrophysiological differences during emotional conflict adaptation processes in preschool children. Thirty children (16 girls, mean age 5.44 ± 0.28 years) completed an emotional Flanker task (stimulus-stimulus cognitive control, S-S) and an emotional Simon task (stimulus-response cognitive control, S-R). Behaviorally, the 5-year-old preschool children exhibited reliable congruency sequence effects (CSEs) in the emotional contexts, with faster response times (RTs) and lower error rates in the incongruent trials preceded by an incongruent trial (iI trial) than in the incongruent trials preceded by a congruent trial (cI trial). Regarding electrophysiology, the children demonstrated longer N2 and P3 latencies in the incongruent trials than in the congruent trials during emotional conflict control processes. Importantly, the boys showed a reliable CSE of N2 amplitude when faced with fearful target expression. Moreover, 5-year-old children showed better emotional CSEs in response to happy targets than to fearful targets as demonstrated by the magnitude of CSEs in terms of the RT, error rate, N2 amplitude and P3 latency. In addition, the results demonstrated that 5-year-old children processed S-S emotional conflicts and S-R emotional conflicts differently and performed better on S-S emotional conflicts than on S-R emotional conflicts according to the comparison of the RT-CSE and P3 latency-CSE values. The current study provides insight into how emotionally salient stimuli affect cognitive processes among preschool children.
Project description:Emotional conflict refers to the influence of task irrelevant affective stimuli on current task set. Previously used emotional face-word tasks have produced certain electrophysiological phenomena, such as an enhanced N450 and slow potential; however, it remains unknown whether these effects emerge in other tasks. The present study used an emotional body-word conflict task to investigate the neural dynamics of emotional conflict as reflected by response time, accuracy, and event-related potentials, which were recorded with the aim of replicating the previously observed N450 and slow potential effect. Results indicated increased response time and decreased accuracy in the incongruent condition relative to the congruent condition, indicating a robust interference effect. Furthermore, the incongruent condition evoked pronounced N450 amplitudes and a more positive slow potential, which might be associated with conflict-monitoring and conflict resolution. The present findings extend our understanding of emotional conflict to the body-word domain.
Project description:The present study examined whether 6-month-old infants could transfer amodal information (i.e. independently of sensory modalities) from emotional voices to emotional faces. Thus, sequences of successive emotional stimuli (voice or face from one sensory modality -auditory- to another sensory modality -visual-), corresponding to a cross-modal transfer, were displayed to 24 infants. Each sequence presented an emotional (angry or happy) or neutral voice, uniquely, followed by the simultaneous presentation of two static emotional faces (angry or happy, congruous or incongruous with the emotional voice). Eye movements in response to the visual stimuli were recorded with an eye-tracker. First, results suggested no difference in infants' looking time to happy or angry face after listening to the neutral voice or the angry voice. Nevertheless, after listening to the happy voice, infants looked longer at the incongruent angry face (the mouth area in particular) than the congruent happy face. These results revealed that a cross-modal transfer (from auditory to visual modalities) is possible for 6-month-old infants only after the presentation of a happy voice, suggesting that they recognize this emotion amodally.
Project description:Major depression goes along with affective and social-cognitive deficits. Most research on affective deficits in depression has, however, only focused on unimodal emotion processing, whereas in daily life, emotional perception is often highly dependent on the evaluation of multimodal inputs. We thus investigated emotional audiovisual integration in patients with depression and healthy subjects. Subjects rated the expression of happy, neutral and fearful faces while concurrently being exposed to emotional or neutral sounds. Results demonstrated group differences in left inferior frontal gyrus and inferior parietal cortex when comparing incongruent to congruent happy facial conditions, mainly due to a failure of patients to deactivate these regions in response to congruent stimulus pairs. Moreover, healthy subjects decreased activation in right posterior superior temporal gyrus/sulcus and midcingulate cortex when an emotional stimulus was paired with a neutral rather than another emotional one. In contrast, patients did not show such deactivation when neutral stimuli were integrated. These results demonstrate aberrant neural response in audiovisual processing in depression, indicated by failure to deactivate regions involved in inhibition and salience processing when congruent and neutral audiovisual stimuli pairs are integrated, providing a possible mechanism of constant arousal and readiness to act in this patient group.
Project description:It can be clinically difficult to distinguish depressed individuals with bipolar disorder (BD) and major depressive disorder (MDD). To examine potential biomarkers of difference between the two disorders, the current study examined differences in the functioning of emotion-processing neural regions during a dynamic emotional faces task.During functional magnetic resonance imaging, healthy control adults (HC) (n = 29) and depressed adults with MDD (n = 30) and BD (n = 22) performed an implicit emotional-faces task in which they identified a color label superimposed on neutral faces that dynamically morphed into one of four emotional faces (angry, fearful, sad, happy). We compared neural activation between the groups in an amygdala region-of-interest and at the whole-brain level.Adults with MDD showed significantly greater activity than adults with BD in the left amygdala to the anger condition (p = 0.01). Results of whole-brain analyses (at p < 0.005, k ? 20) revealed that adults with BD showed greater activity to sad faces in temporoparietal regions, primarily in the left hemisphere, whereas individuals with MDD demonstrated greater activity than those with BD to displays of anger, fear, and happiness. Many of the observed BD-MDD differences represented abnormalities in functioning compared to HC.We observed a dissociation between depressed adults with BD and MDD in the processing of emerging emotional faces. Those with BD showed greater activity during mood-congruent (i.e., sad) faces, whereas those with MDD showed greater activity for mood-incongruent (i.e., fear, anger, and happy) faces. Such findings may reflect markers of differences between BD and MDD depression in underlying pathophysiological processes.
Project description:The present study used event-related potentials (ERPs) to investigate the function of signals induced by cognitive conflict during the detection stage and the resolution stage of perceptual processing. The study used a combination of the Stroop task and an affective priming task to examine the conflict priming effect when the stimulus onset asynchrony (SOA) was 200 ms or 800 ms. Behavioral results showed that the RTs were shorter for positive targets following congruent primes relative to incongruent primes, and for negative targets following incongruent primes relative to congruent primes when the SOA was 200 ms. ERP results showed that the N2 amplitudes (200-300 ms) for incongruent stimuli were significantly larger than for congruent stimuli in the Stroop task, which indicated a significant conflict effect. Moreover, the N400 amplitudes (500-700 ms) for positive targets after congruent primes were significantly lower than those after incongruent primes when the SOA was 200 ms, which showed a significant negative priming effect. While the SOA was 800 ms, behavioral results showed that the RTs were shorter for positive targets following incongruent primes relative to congruent primes. ERP results showed that the N2 amplitudes (200-300 ms) for incongruent stimuli were significantly larger than for congruent stimuli in the Stroop task, which indicated a significant conflict effect. The N400 amplitudes (1100-1300 ms) for the negative targets after congruent primes were significantly lower than those after incongruent primes when the SOA was 800 ms, which showed a significant positive priming effect. The results demonstrated that the functions of signals induced by cognitive conflict were reversed in two different cognitive processing stages.
Project description:Cognitive control supports goal-directed behavior by resolving conflict among opposing action tendencies. Emotion can trigger cognitive control processes, thus speeding up conflict processing when the target dimension of stimuli is emotional. However, it is unclear what role emotionality of the target dimension plays in the processing of emotional conflict (e.g. in irony). In two EEG experiments, we compared the influence of emotional valence of the target (emotional, neutral) in cognitive and emotional conflict processing. To maximally approximate real-life communication, we used audiovisual stimuli. Participants either categorized spoken vowels (cognitive conflict) or their emotional valence (emotional conflict), while visual information was congruent or incongruent. Emotional target dimension facilitated both cognitive and emotional conflict processing, as shown in a reduced reaction time conflict effect. In contrast, the N100 in the event-related potentials showed a conflict-specific reversal: the conflict effect was larger for emotional compared with neutral trials in cognitive conflict and smaller in emotional conflict. Additionally, domain-general conflict effects were observed in the P200 and N200 responses. The current findings confirm that emotions have a strong influence on cognitive and emotional conflict processing. They also highlight the complexity and heterogeneity of the interaction of emotion with different types of conflict.
Project description:Previous studies regarding age-related changes in proactive control were inconclusive and the effects of emotion on proactive control in ageing are yet to be determined. Here, we assessed the role of task-relevant emotion on proactive control in younger and older adults. Proactive control was manipulated by varying the proportion of conflict trials in an emotional Stroop task. In Experiment 1, emotional target faces with congruent, incongruent or non-word distractor labels were used to assess proactive control in younger and older adults. To investigate whether the effects of emotion are consistent across different stimulus types, emotional target words with congruent, incongruent or obscured distractor faces were used in Experiment 2. Data from this study showed that older adults successfully deployed proactive control when needed and that task-relevant emotion affected cognitive control similarly in both age groups. It was also found that the effects of emotion on cognitive performance were qualitatively different for faces and words, with facilitating effects being observed for happy faces and for negative words. Overall, these results suggest that the effects of emotion and age on proactive control depend on the task at hand and the chosen stimulus set.
Project description:CONTEXT:Major depressive disorder (MDD) is associated with behavioral and neurophysiological evidence of mood-congruent processing biases toward explicitly presented, emotionally valenced stimuli. However, few studies have investigated such biases toward implicitly presented stimuli. OBJECTIVE:To investigate differential amygdala responses to sad, happy, and neutral faces presented below the level of explicit conscious awareness using a backward masking task in unmedicated participants with MDD and healthy controls (HCs). DESIGN:Initial cross-sectional design followed by a longitudinal treatment trial using functional magnetic resonance imaging. SETTING:Psychiatric outpatient clinic at the National Institute of Mental Health. PARTICIPANTS:We studied 22 unmedicated, currently depressed people with MDD (dMDD), 16 unmedicated individuals with MDD in full remission (rMDD), and 25 HCs. INTERVENTION:Ten dMDD participants underwent 8 weeks of antidepressant treatment with the selective serotonin reuptake inhibitor sertraline hydrochloride. MAIN OUTCOME MEASURES:Amygdala region-of-interest and whole-brain analyses evaluated the hemodynamic response during exposure to masked sad vs masked happy faces, to masked sad vs neutral faces, and to masked happy vs neutral faces. RESULTS:The dMDD participants showed greater amygdala responses than HCs to masked sad faces, whereas HCs showed greater amygdala responses to masked happy faces. The bias toward sad faces also was evident in rMDD participants relative to HCs and did not differ between dMDD and rMDD participants. This processing bias reversed toward the normative pattern in dMDD participants after sertraline treatment. CONCLUSIONS:Emotional-processing biases occur in amygdala responses to sad faces presented below the level of conscious awareness in dMDD or rMDD individuals and to happy faces in HCs. By influencing the salience of social stimuli, mood-congruent processing biases in the amygdala may contribute to dysfunction in conscious perceptions and social interactions in MDD. Our data suggest, however, that the negative bias resolves and a positive bias develops in patients with MDD during selective serotonin reuptake inhibitor treatment.