Event-related brain potential correlates of emotional face processing

Results from recent event-related brain potential (ERP) studies investigating brain processes involved in the detection and analysis of emotional facial expression are reviewed. In all experiments, emotional faces were found to trigger an increased ERP positivity relative to neutral faces. The onset of this emotional expression effect was remarkably early, ranging from 120 to 180ms post-stimulus in different experiments where faces were either presented at fixation or laterally, and with or without non-face distractor stimuli. While broadly distributed positive deflections beyond 250ms post-stimulus have been found in previous studies for non-face stimuli, the early frontocentrally distributed phase of this emotional positivity is most likely face-specific. Similar emotional expression effects were found for six basic emotions, suggesting that these effects are not primarily generated within neural structures specialised for the automatic detection of specific emotions. Expression effects were eliminated when attention was directed away from the location of peripherally presented emotional faces, indicating that they are not linked to pre-attentive emotional processing. When foveal faces were unattended, expression effects were attenuated, but not completely eliminated. It is suggested that these ERP correlates of emotional face processing reflect activity within a neocortical system where representations of emotional content are generated in a task-dependent fashion for the adaptive intentional control of behaviour. Given the early onset of the emotion-specific effects reviewed here, it is likely that this system is activated in parallel with the ongoing evaluation of emotional content in the amygdala and related subcortical brain circuits.     

Dissociable meta‐analytic brain networks contribute to coordinated emotional processing

Meta‐analytic techniques for mining the neuroimaging literature continue to exert an impact on our conceptualization of functional brain networks contributing to human emotion and cognition. Traditional theories regarding the neurobiological substrates contributing to affective processing are shifting from regional‐ towards more network‐based heuristic frameworks. To elucidate differential brain network involvement linked to distinct aspects of emotion processing, we applied an emergent meta‐analytic clustering approach to the extensive body of affective neuroimaging results archived in the BrainMap database. Specifically, we performed hierarchical clustering on the modeled activation maps from 1,747 experiments in the affective processing domain, resulting in five meta‐analytic groupings of experiments demonstrating whole‐brain recruitment. Behavioral inference analyses conducted for each of these groupings suggested dissociable networks supporting: (1) visual perception within primary and associative visual cortices, (2) auditory perception within primary auditory cortices, (3) attention to emotionally salient information within insular, anterior cingulate, and subcortical regions, (4) appraisal and prediction of emotional events within medial prefrontal and posterior cingulate cortices, and (5) induction of emotional responses within amygdala and fusiform gyri. These meta‐analytic outcomes are consistent with a contemporary psychological model of affective processing in which emotionally salient information from perceived stimuli are integrated with previous experiences to engender a subjective affective response. This study highlights the utility of using emergent meta‐analytic methods to inform and extend psychological theories and suggests that emotions are manifest as the eventual consequence of interactions between large‐scale brain networks.     

抑郁症患者情绪图片刺激早期低频脑磁图研究

目的：探讨抑郁症患者给予视觉情绪图片刺激早期0～100ms、100～200ms、200～300ms3个时段8～30Hz的神经磁场激活特征。方法：8例抑郁症患者及12例健康右利手对照者,在给予国际情绪图片库（IAPS）正性、中性、负性情绪图片刺激同时记录脑磁图信号,使用SPM8b软件进行数据分析：设两样本t检验P〈0.01（未校正）和K值≥10个体素范围为差异有统计学意义。结果：与对照组相比,抑郁组在正性情绪图片刺激下,100～200ms内的左侧额下回,右侧的终板旁回、额内侧回、海马回激活增强。在中性情绪图片刺激下,抑郁组在0～100ms的右侧豆状核、岛叶、额上回,左内侧额叶,100～200ms内的右侧岛叶、豆状核壳核及屏状核,左侧额下回、额上回、颞上回,200～300ms内的右侧岛叶、豆状核、尾状核体激活增强。负性情绪图片刺激下抑郁组在0～100ms内的右侧颞上回、岛叶、尾状核头部、额中下回激活增强,100～200ms内的右侧额中回、尾状核体,200～300ms内右额下回激活增强。此外还比较一致的发现抑郁组在楔前叶、后扣带回等顶叶脑区激活降低。结论：抑郁个体起注意调节功能的顶叶脑区如楔前叶功能不足,对视觉皮质向前部脑区情绪信息颞叶底部传递通路抑制不足,腹侧前额皮质、岛叶过度的激活,可能是抑郁症的一个发病基础。     

The neural networks of subjectively evaluated emotional conflicts

Previous work on the neural underpinnings of emotional conflict processing has largely focused on designs that instruct participants to ignore a distracter which conflicts with a target. In contrast, this study investigated the noninstructed experience and evaluation of an emotional conflict, where positive or negative cues can be subjectively prioritized. To this end, healthy participants freely watched short film scenes that evoked emotional conflicts while their BOLD responses were measured. Participants' individual ratings of conflict and valence perception during the film scenes were collected immediately afterwards, and the individual ratings were regressed against the BOLD data. Our analyses revealed that (a) amygdala and medial prefrontal cortex were significantly involved in prioritizing positive or negative cues, but not in subjective evaluations of conflict per se, and (b) superior temporal sulcus (STS) and inferior parietal lobule (IPL), which have been implicated in social cognition and emotion control, were involved in both prioritizing positive or negative cues and subjectively evaluating conflict, and may thus constitute “hubs” or “switches” in emotional conflict processing. Psychophysiological interaction (PPI) analyses further revealed stronger functional connectivity between IPL and ventral prefrontal—medial parietal areas in prioritizing negative cues, and stronger connectivity between STS and dorsal‐rostral prefrontal—medial parietal areas in prioritizing positive cues. In sum, our results suggest that IPL and STS are important in the subjective evaluation of complex conflicts and influence valence prioritization via prefrontal and parietal control centers. Hum Brain Mapp 37:2234–2246, 2016. © 2016 Wiley Periodicals, Inc.     

Altered brain activity during emotional empathy in somatoform disorder

Somatoform disorder patients suffer from impaired emotion recognition and other emotional deficits. Emotional empathy refers to the understanding and sharing of emotions of others in social contexts. It is likely that the emotional deficits of somatoform disorder patients are linked to disturbed empathic abilities; however, little is known so far about empathic deficits of somatoform patients and the underlying neural mechanisms. We used fMRI and an empathy paradigm to investigate 20 somatoform disorder patients and 20 healthy controls. The empathy paradigm contained facial pictures expressing anger, joy, disgust, and a neutral emotional state; a control condition contained unrecognizable stimuli. In addition, questionnaires testing for somatization, alexithymia, depression, empathy, and emotion recognition were applied. Behavioral results confirmed impaired emotion recognition in somatoform disorder and indicated a rather distinct pattern of empathic deficits of somatoform patients with specific difficulties in “empathic distress.” In addition, somatoform patients revealed brain areas with diminished activity in the contrasts “all emotions”–“control,” “anger”–“control,” and “joy”–“control,” whereas we did not find brain areas with altered activity in the contrasts “disgust”–“control” and “neutral”–“control.” Significant clusters with less activity in somatoform patients included the bilateral parahippocampal gyrus, the left amygdala, the left postcentral gyrus, the left superior temporal gyrus, the left posterior insula, and the bilateral cerebellum. These findings indicate that disturbed emotional empathy of somatoform disorder patients is linked to impaired emotion recognition and abnormal activity of brain regions responsible for emotional evaluation, emotional memory, and emotion generation. Hum Brain Mapp, 2012. © 2011 Wiley Periodicals, Inc.     

Masked facial affect priming is associated with therapy response in clinical depression

In the present study, automatic processing of facial affect in clinical depression was investigated in the course of an inpatient treatment program. Patients suffering from clinical depression (n = 20) and healthy controls (n = 21) completed the facial affective priming task developed by Murphy and Zajonc (1993) twice, about 7 weeks apart. Subjects were instructed to evaluate neutral Chinese ideographs primed by masked displays of sad, happy, and neutral facial affect, including a no–prime condition. In the course of treatment, patients recovered significantly. In acutely depressed patients, no priming based on emotional faces could be found compared to neutral faces at time 1. However, compared to the no–prime condition, negative evaluation shifts elicited by neutral and sad faces were found which were significantly correlated with symptom severity. Patients with persisting high levels of depression after therapy judged ideographs more negatively in all three facial prime conditions at time 1. We conclude that clinically depressed patients are characterized by automatic processing biases for facial affect. An enhanced sensitivity for sad facial expressions and a negatively biased automatic processing of neutral and happy facial affect appears to be associated with depression persistence.     

Understanding semantic and phonological processing deficits in adults with aphasia: effects of category and typicality

Background: Semantic and phonological processing deficits are often present in aphasia. The degree of interdependence between the deficits has been widely studied with variable findings. Semantic variables such as category and typicality have been found to influence semantic processing in healthy individuals and persons with aphasia (PWA), but their influence on phonological processing is unknown.

Aims: This study examined the nature of semantic and phonological access in aphasia by comparing adults with aphasia to healthy control participants. Semantic and phonological tasks were used to assess the difference in processing requirements between and within each group as well as examine the effects of category and typicality on different stages of semantic and phonological processing.

Methods & Procedures: Thirty-two PWA and 10 neurologically healthy adults were administered nine tasks: Category Superordinate, Category Coordinate, Semantic Feature, Rhyme Judgment (No-Name), Syllable Judgment (No-Name), Phoneme Verification (No-Name), Rhyme Judgment (Name-Provided), Syllable Judgment (Name-Provided), and Phoneme Verification (Name-Provided). Accuracy and reaction time (RT) data were collected for each of these tasks and between-group and within-group differences were analysed via MANOVA/MANCOVA and hierarchical clustering analyses.

Outcomes & Results: PWA performed with significantly lower accuracy than controls on phonological tasks but performed comparably on semantic tasks. Participants with aphasia were significantly slower than controls on all semantic and phonological tasks. Clustering of the nine tasks by accuracy revealed different processing requirements in the participants with aphasia compared to the control group while clustering by RT revealed similar trends in both groups in that phonological (no-name) items required the most processing time. Significant effects of category and typicality were noted in the semantic tasks but not in any of the phonological tasks.

Conclusions: Individuals with aphasia demonstrated overall impaired phonological processing with relatively preserved semantic processing as compared to controls. Per accuracy and RT measures, distinct trends in processing load for semantic tasks versus phonological tasks were seen in the individuals with aphasia whereas only speed of processing and not accuracy was impacted by phonological processing load in the control group. The results align most closely with discrete serial processing models of lexical processing as category and typicality effects were robust in the semantic tasks but not in any of the phonological tasks. Alternative explanations for these results also are discussed.     

Common and distinct brain networks underlying explicit emotional evaluation: a meta-analytic study

Brain mechanisms underlying explicit evaluation of emotion have been explored using different tasks including ‘stimulus-focused evaluation’, ‘evaluation of one''s own emotion’ and ‘evaluation of others’ emotions’. Yet the extent to which similar brain mechanisms underlie different evaluation tasks is unclear. A meta-analysis of published neuroimaging studies of explicit emotional evaluation was conducted to examine common and distinct regions underlying these different evaluation tasks. This study revealed regions common to all three tasks: The amygdala and LPFC as common regions may be involved in emotion–cognition interactions, and the DMPFC may possibly play integrative roles in explicit emotional evaluation. Distinct regions were also identified: (i) the sensory cortex and VLPFC were specifically associated with ‘stimulus evaluation’, possibly involved in perceptual and conceptual processing; (ii) the insula and rACC were specifically associated with ‘evaluation of one''s own emotion’, potentially associated with interoceptive and experiential processing; and (iii) the STS and TPJ were specifically associated with ‘evaluation of others’ emotions’, potentially reflecting their roles in TOM and empathy. These findings suggest that different types of explicit emotional evaluation may involve common and distinct networks and provide new insights on multiple mechanisms underlying explicit emotional evaluation.     

Age-related differences in brain activity underlying identification of emotional expressions in faces

We used fMRI to explore brain activity in young and old adults,while they viewed and labeled faces expressing different emotionsas well as neutral expressions. Older adults had significantlygreater difficulty identifying expressions of sadness, angerand disgust than young adults. Both groups performed at ceilingfor happy expressions. The functional neuroimaging data revealedthat both young and old adults recruited a pattern of activitythat distinguished happy expressions from all other expressions,but the patterns were age-specific. Older adults showed increasedactivity in ventromedial prefrontal cortex, lingual gyrus andpremotor cortex for happy expressions, whereas younger adultsrecruited a more widely distributed set of regions includingthe amgydala, ventromedial prefrontal cortex, lateral prefrontalregions and bilateral inferior parietal and superior temporalareas. Conversely, younger adults showed more activity in thedorsal anterior cingulate for other types of expressions, andolder adults had more activity in dorsal cingulate, as wellas middle and inferior frontal gyri, somatosensory cortex, insulaand middle temporal regions. These results support previousresearch demonstrating age differences in brain activity duringemotional processing, and suggest possible age-related differencesin cognitive strategy during identification of happy faces,despite no effect of age on this ability.     

Risk for depression is associated with neural biases in emotional categorisation

Negative biases in emotional processing are a major characteristic of depression. Recent research has shown that such negative biases are evident in high risk individuals even in the absence of personal history of depression, suggesting that they may serve as key vulnerability markers of depression. However, the neural basis of these behavioural observations has not been fully explored. This study therefore aimed to (1) illustrate the neural processes involved in the categorisation of emotional personality-trait words; and (2) examine whether these neural mechanisms are biased towards negative information in high risk individuals. Risk for depression was defined by high neuroticism (N). We recruited a sample of high risk (high N) and low risk (low N) never-depressed young adults. Functional magnetic resonance imaging (fMRI) was acquired during the categorisation and memory for positive and negative self-referent personality-trait words (e.g. honest, rude). High risk volunteers showed greater responses in the right superior parietal cortex than low risk volunteers specifically during the categorisation of negative words. Moreover, neuroticism score was positively correlated with neural responses in the left anterior cingulate during the categorisation of negative words but negatively correlated within the same region during the retrieval of these words. These results highlight a role of the fronto-parietal circuitry in emotional processing and further suggest that negative biases in these neural processes may be involved in risk for depression.     

Prediction errors to emotional expressions: the roles of the amygdala in social referencing

Social referencing paradigms in humans and observational learning paradigms in animals suggest that emotional expressions are important for communicating valence. It has been proposed that these expressions initiate stimulus-reinforcement learning. Relatively little is known about the role of emotional expressions in reinforcement learning, particularly in the context of social referencing. In this study, we examined object valence learning in the context of a social referencing paradigm. Participants viewed objects and faces that turned toward the objects and displayed a fearful, happy or neutral reaction to them, while judging the gender of these faces. Notably, amygdala activation was larger when the expressions following an object were less expected. Moreover, when asked, participants were both more likely to want to approach, and showed stronger amygdala responses to, objects associated with happy relative to objects associated with fearful expressions. This suggests that the amygdala plays two roles in social referencing: (i) initiating learning regarding the valence of an object as a function of prediction errors to expressions displayed toward this object and (ii) orchestrating an emotional response to the object when value judgments are being made regarding this object.     

Nonlinear relationship between emotional valence and brain activity: Evidence of separate negative and positive valence dimensions

Emotion plays a significant role in goal‐directed behavior, yet its neural basis is yet poorly understood. In several psychological models the cardinal dimensions that characterize the emotion space are considered to be valence and arousal. Here 3T functional magnetic resonance imaging (fMRI) was used to reveal brain areas that show valence‐ and arousal‐dependent blood oxygen level dependent (BOLD) signal responses. Seventeen healthy adults viewed pictures from the International Affective Picture System (IAPS) for brief 100 ms periods in a block design paradigm. In many brain regions BOLD signals correlated significantly positively with valence ratings of unpleasant pictures. Interestingly, partly in the same regions but also in several other regions BOLD signals correlated negatively with valence ratings of pleasant pictures. Therefore, there were several areas where the correlation across all pictures was of inverted U‐shape. Such correlations were found bilaterally in the dorsolateral prefrontal cortex (DLPFC), dorsomedial prefrontal cortex (DMPFC) extending to anterior cingulate cortex (ACC), and insula. Self‐rated arousal of those pictures which were evaluated to be unpleasant correlated with BOLD signal in the ACC, whereas for pleasant pictures arousal correlated positively with the BOLD signal strength in the right substantia innominata. We interpret our results to suggest a major division of brain mechanisms underlying affective behavior to those evaluating stimuli to be pleasant or unpleasant. This is consistent with the basic division of behavior to approach and withdrawal, where differentiation of hostile and hospitable stimuli is crucial. Hum Brain Mapp, 2010. © 2009 Wiley‐Liss, Inc.     

Differences in neural activity when processing emotional arousal and valence in autism spectrum disorders

Individuals with autism spectrum disorders (ASD) often have difficulty recognizing and interpreting facial expressions of emotion, which may impair their ability to navigate and communicate successfully in their social, interpersonal environments. Characterizing specific differences between individuals with ASD and their typically developing (TD) counterparts in the neural activity subserving their experience of emotional faces may provide distinct targets for ASD interventions. Thus we used functional magnetic resonance imaging (fMRI) and a parametric experimental design to identify brain regions in which neural activity correlated with ratings of arousal and valence for a broad range of emotional faces. Participants (51 ASD, 84 TD) were group‐matched by age, sex, IQ, race, and socioeconomic status. Using task‐related change in blood‐oxygen‐level‐dependent (BOLD) fMRI signal as a measure, and covarying for age, sex, FSIQ, and ADOS scores, we detected significant differences across diagnostic groups in the neural activity subserving the dimension of arousal but not valence. BOLD‐signal in TD participants correlated inversely with ratings of arousal in regions associated primarily with attentional functions, whereas BOLD‐signal in ASD participants correlated positively with arousal ratings in regions commonly associated with impulse control and default‐mode activity. Only minor differences were detected between groups in the BOLD signal correlates of valence ratings. Our findings provide unique insight into the emotional experiences of individuals with ASD. Although behavioral responses to face‐stimuli were comparable across diagnostic groups, the corresponding neural activity for our ASD and TD groups differed dramatically. The near absence of group differences for valence correlates and the presence of strong group differences for arousal correlates suggest that individuals with ASD are not atypical in all aspects of emotion‐processing. Studying these similarities and differences may help us to understand the origins of divergent interpersonal emotional experience in persons with ASD. Hum Brain Mapp 37:443–461, 2016. © 2015 Wiley Periodicals, Inc.     

Emotion regulation modulates anticipatory brain activity that predicts emotional memory encoding in women

It has been shown that the effectiveness with which unpleasant events are encoded into memory is related to brain activity set in train before the events. Here, we assessed whether encoding-related activity before an aversive event can be modulated by emotion regulation. Electrical brain activity was recorded from the scalps of healthy women while they performed an incidental encoding task on randomly intermixed unpleasant and neutral visual scenes. A cue presented 1.5 s before each picture indicated the upcoming valence. In half of the blocks of trials, the instructions emphasized to let emotions arise in a natural way. In the other half, participants were asked to decrease their emotional response by adopting the perspective of a detached observer. Memory for the scenes was probed 1 day later with a recognition memory test. Brain activity before unpleasant scenes predicted later memory of the scenes, but only when participants felt their emotions and did not detach from them. The findings indicate that emotion regulation can eliminate the influence of anticipatory brain activity on memory encoding. This may be relevant for the understanding and treatment of psychiatric diseases with a memory component.     

Spared emotional perception in patients with Alzheimer's disease is associated with negative caregiver outcomes

Objectives: Caregivers (CGs) for patients with Alzheimer's disease (AD) often experience negative mental health and relationship outcomes. Additionally, emotional perception abilities are often compromised in early AD; the relationships between these deficits and CG outcomes are unclear. The present study investigated the relationship between emotional perception abilities in AD participants and CG well-being.

Methods: Participants included 28 individuals with AD, their spousal CGs, and 30 older controls (OCs). Patients and controls completed the Montreal Cognitive Assessment and Advanced Clinical Solutions: Social Perception subtest. CGs completed questionnaires related to relationship satisfaction, burden, depression, and patient neuropsychiatric symptoms and activities of daily living.

Results: The patient group performed significantly worse than OCs on measures of cognition and emotional perception. Several significant relationships emerged between AD participant emotional perception and CG outcomes. Higher CG depression was associated with greater overall emotional perception abilities (r = .39, p = .041). Caregiver burden was positively correlated with AD participants' ability to label the emotional tones of voices (r = .47, p = .015). Relationship satisfaction was not significantly correlated with emotional perception.

Discussion: This study replicated earlier findings of impaired emotional perception abilities in AD participants. However, preserved abilities in emotional perception were associated greater CG depression and burden. Interestingly, the CGs satisfaction with the marital relationship did not appear to be influenced by changes in emotional perception. Higher emotional engagement among couples in which one spouse has cognitive impairment may contribute to increased negative interactions and in turn a greater sense of burden and depression, while leaving the marital relationship preserved.     

Early stressful experiences are associated with reduced neural responses to naturalistic emotional and social content in children

How do children’s experiences relate to their naturalistic emotional and social processing? Because children can struggle with tasks in the scanner, we collected fMRI data while 4-to-11-year-olds watched a short film with positive and negative emotional events, and rich parent-child interactions (n = 70). We captured broad, normative stressful experiences by examining socioeconomic status (SES) and stressful life events, as well as children’s more proximal experiences with their parents. For a sub-sample (n = 30), parenting behaviors were measured during a parent-child interaction, consisting of a picture book, a challenging puzzle, and free play with novel toys. We characterized positive parenting behaviors (e.g., warmth, praise) and negative parenting behaviors (e.g., harsh tone, physical control). We found that higher SES was related to greater activity in medial orbitofrontal cortex during parent-child interaction movie events. Negative parenting behaviors were associated with less activation of the ventral tegmental area and cerebellum during positive emotional events. In a region-of-interest analysis, we found that stressful life events and negative parenting behaviors were associated with less activation of the amygdala during positive emotional events. These exploratory results demonstrate the promise of using movie fMRI to study how early experiences may shape emotional, social, and motivational processes.     

Synthetic PET: Analyzing large-scale properties of neural networks

Synthetic PET is introduced as a new computational technique for connecting neural network studies based on animal data and image studies of human brain function. Synthetic PET comparisons are taken from a computational model of interacting neural networks in, for example, the monkey brain by integrating synaptic activity in each subnetwork as different simulated tasks are performed. Given a pair of tasks, comparative synaptic activity levels for each modeled neural region are then painted into the homologous regions of a three-dimensional model of the human brain corresponding to the Talairach atlas. The resulting comparison then offers predictions of relative changes of neuronal activity as obtained from PET comparisons of humans performing a similar pair of tasks. Where neurophysiological data and individual arrays of neural networks give us a very fine-grained view of the behavior of just a few neurons within nonhumans, PET measures provide a more global view of brain function. Synthetic PET allows us to integrate human and monkey studies in the construction of more complete models of the neural mechanisms used by both species in similar tasks. The technique is demonstrated in a saccade generation task. The method readily generalizes to other forms of brain imaging. © 1995 Wiley-Liss, Inc.     

Impact of voice on emotional judgment of faces: an event-related fMRI study

Emotional information can be conveyed by various means of communication, such as propositional content, speech intonation, facial expression, and gestures. Prior studies have demonstrated that inputs from one modality can alter perception in another modality. To evaluate the impact of emotional intonation on ratings of emotional faces, a behavioral study first was carried out. Second, functional magnetic resonance (fMRI) was used to identify brain regions that mediate crossmodal effects of emotional prosody on judgments of facial expressions. In the behavioral study, subjects rated fearful and neutral facial expressions as being more fearful when accompanied by a fearful voice as compared to the same facial expressions without concomitant auditory stimulus, whereas no such influence on rating of faces was found for happy voices. In the fMRI experiment, this shift in rating of facial expressions in presence of a fearfully spoken sentence was correlated with the hemodynamic response in the left amygdala extending into the periamygdaloid cortex, which suggests that crossmodal effects on cognitive judgments of emotional information are mediated via these neuronal structures. Furthermore, significantly stronger activations were found in the mid-portion of the right fusiform gyrus during judgment of facial expressions in presence of fearful as compared to happy intonations, indicating that enhanced processing of faces within this region can be induced by the presence of threat-related information perceived via the auditory modality. Presumably, these increased extrastriate activations correspond to enhanced alertness, whereas responses within the left amygdala modulate cognitive evaluation of emotional facial expressions.     

Perceiving emotions in neutral faces: expression processing is biased by affective person knowledge

According to a widely held view, basic emotions such as happiness or anger are reflected in facial expressions that are invariant and uniquely defined by specific facial muscle movements. Accordingly, expression perception should not be vulnerable to influences outside the face. Here, we test this assumption by manipulating the emotional valence of biographical knowledge associated with individual persons. Faces of well-known and initially unfamiliar persons displaying neutral expressions were associated with socially relevant negative, positive or comparatively neutral biographical information. The expressions of faces associated with negative information were classified as more negative than faces associated with neutral information. Event-related brain potential modulations in the early posterior negativity, a component taken to reflect early sensory processing of affective stimuli such as emotional facial expressions, suggest that negative affective knowledge can bias the perception of faces with neutral expressions toward subjectively displaying negative emotions.     

抑郁症首次发作患者情绪偏向任务的脑功能磁共振成像研究

目的 研究抑郁症首次发作(以下简称首发)患者对不同性质情绪线索的差异脑激活反应,以探讨抑郁症患者"负性情绪偏向性"的脑活动特征.方法 14例抑郁症首发患者与14名配对健康对照者,接受国际情绪图片系统中正性-中性-负性三组图片刺激的脑功能磁共振成像(fMRI)扫描,任务为组块设计;以文拉法辛(75～150 mg/d,口服)治疗患者,随访12周;以汉密尔顿抑郁量表(HAMD17)减分率评估疗效;用神经功能影像分析(AFNI)软件处理影像数据.结果 (1)文拉法辛治疗8周时有效率为58%;12周时有效率为92%,HAMD17总分减分率为60%.(2)两组均激活的脑区包括双侧额中回、双侧背外侧前额叶皮质、左侧丘脑、双侧岛叶、双侧颞叶、双侧杏仁核和海马.(3)在正性/中性图片激活的脑区中,患者组双侧额中回(右侧0.11%,左侧0.09%)及左侧丘脑(0.31%)激活强度均低于对照组(分别为0.98%,1.17%和1.32%;P＜0.05);左侧岛叶(1.03%)及双侧杏仁核(右侧0.47%,左侧0.11%)的激活强度高于对照组(分别为0.45%,-0.34%和-0.49%;P＜0.05).对于负性图片,患者组左侧额中回(2.77%)、左背外侧前额叶皮质(0.18%)、左侧岛叶(1.36%)、左侧颞叶(0.33%)和右侧杏仁核(0.44%)的激活强度高于对照组(分别为1.91%.-0.32%.0.91%,-0.31%,-0.29%;P＜0.05);患者组左侧丘脑激活强度(-0.79%)低于对照组(1.15%;P＜0.05).(4)治疗后,对于正性图片,患者组左侧、右侧额中回及左侧丘脑激活增加为1.21%,1.14%及1.23%(P＜0.05).对于负性图片,左侧额中回(2.05%)、左外侧前额叶皮质(-0.42%)及左侧岛叶(0.73%)的激活降低(P＜0.05);左侧丘脑(1.53%)激活增加(P＜0.05).结论 前额叶、左侧岛叶、左侧颞叶、杏仁核和左侧丘脑对不同性质情绪诱导线索的异常激活,与抑郁症首发患者偏向性情绪障碍相关;文拉法辛对前额叶、左侧岛叶和丘脑的异常激活有调节作用.