Reduced neural activity of the prefrontal cognitive control circuitry during response inhibition to negative words in people with schizophrenia

Background

Schizophrenia is characterized by deficits in executive control and impairments in emotion processing. This study assessed the nature and extent of potential alterations in the neural substrates supporting the interaction between cognitive control mechanisms and emotion attribution processes in people with schizophrenia.

Methods

Functional magnetic resonance imaging was performed during a verbal emotional go/no-go task. People with schizophrenia and healthy controls responded to word stimuli of a prespecified emotional valence (positive, negative or neutral) while inhibiting responses to stimuli of a different valence.

Results

We enrolled 20 people with schizophrenia and 23 controls in the study. Healthy controls activated an extensive dorsal prefrontal–parietal network while inhibiting responses to negative words compared to neutral words, but showed deactivation of the midcingulate cortex while inhibiting responses to positive words compared to neutral words. People with schizophrenia failed to activate this network during response inhibition to negative words, whereas during response inhibition to positive words they did not deactivate the cingulate, but showed increased responsivity in the frontal cortex.

Limitations

Sample heterogeneity is characteristic of studies of schizophrenia and may have contributed to more variable neural responses in the patient sample despite the care taken to control for potentially confounding variables.

Conclusion

Our results showed that schizophrenia is associated with aberrant modulation of neural responses during the interaction between cognitive control and emotion processing. Failure of the frontal circuitry to regulate goal-directed behaviour based on emotion attributions may contribute to deficits in psychosocial functioning in daily life.     

The influence of positive and negative emotional associations on semantic processing in depression: An fMRI study

In depression, patients suffer from emotional and cognitive deficits, among others in semantic processing. If these semantic deficits are cognitive or interact with emotional dysfunctions, is still an open question. The aim of the current study was to investigate the influence of emotional valence on the neural correlates of semantic priming in major depression. In a lexical decision task, positive, negative, and neutral word pairs were presented during fMRI measurement. Nineteen inpatients and 19 demographically matched controls were recruited. Behaviorally, positive and neutral valence induced a priming effect whereas negative valence induced no effect (controls) or even inhibition (slower RT for related stimuli) in patients. At the neural level, the semantic relation effect revealed similar neural activation in right middle frontal regions for patients and controls. Group differences emerged in the right fusiform gyrus and the ACC. Activity associated with positive valence differed at the DLPFC and amygdala and for negative valence at putamen and cerebellum. The activation of amygdala and DLPFC correlated negatively with the severity of depression. To conclude, semantic processing deficits in depression are modulated by emotional valence of the stimulus on the behavioral as well as on neural level in right‐lateralized prefrontal areas and the amygdala. The results highlighted an influence of depression severity on emotion information processing as the severity of symptoms correlated negatively with neural responses to positively and negatively valenced information. Hence, the dysfunctional emotion processing may further enhance the cognitive deficits in depression. Hum Brain Mapp 35:471–482, 2014. © 2012 Wiley Periodicals, Inc.     

Neural substrates of olfactory processing in schizophrenia patients and their healthy relatives

Odorants represent powerful stimuli capable of eliciting various emotional responses. In schizophrenia patients and their non-affected relatives, olfactory and emotional functions are impaired, revealing a familial influence on these deficits. We aimed at determining the neural basis of emotional olfactory dysfunctions using odors of different emotional valence for mood induction and functional magnetic resonance imaging (fMRI) by comparing 13 schizophrenia patients, their non-affected brothers and 26 matched healthy controls. Blood-oxygen-level-dependent (BOLD) effects and subjective mood changes were assessed during negative (rotten yeast), positive (vanilla) and neutral (ambient air) olfactory stimulation. Group comparisons of brain activation were performed in regions of interest. Subjective ratings were comparable between groups and indicated successful mood induction. However, during stimulation with the negative odor, hypofunctional activity emerged in regions of the right frontal and temporal cortex in the patients. A familial influence in the neural substrates of negative olfactory dysfunction was indicated by a similar reduced frontal brain activity in relatives. Dysfunctions therefore appeared to be located in regions involved in higher cognitive processes associated with olfaction. No familial influences were indicated for cerebral dysfunctions during positive olfactory stimulation. Results point to a differentiation between trait and state components in cerebral dysfunctions during emotional olfactory processing in schizophrenia.     

An fMRI study of facial emotion processing in patients with schizophrenia

OBJECTIVE: Emotion processing deficits are notable in schizophrenia. The authors evaluated cerebral blood flow response in schizophrenia patients during facial emotion processing to test the hypothesis of diminished limbic activation related to emotional relevance of facial stimuli. METHOD: Fourteen patients with schizophrenia and 14 matched comparison subjects viewed facial displays of happiness, sadness, anger, fear, and disgust as well as neutral faces. Functional magnetic resonance imaging was used to measure blood-oxygen-level-dependent signal changes as the subjects alternated between tasks of discriminating emotional valence (positive versus negative) and age (over 30 versus under 30) of the faces with an interleaved crosshair reference condition. RESULTS: The groups did not differ in performance on either task. For both tasks, healthy participants showed activation in the fusiform gyrus, occipital lobe, and inferior frontal cortex relative to the resting baseline condition. The increase was greater in the amygdala and hippocampus during the emotional valence discrimination task than during the age discrimination task. In the patients with schizophrenia, minimal focal response was observed for all tasks relative to the resting baseline condition. Contrasting patients and comparison subjects on the emotional valence discrimination task revealed voxels in the left amygdala and bilateral hippocampus in which the comparison subjects had significantly greater activation. CONCLUSIONS: Failure to activate limbic regions during emotional valence discrimination may explain emotion processing deficits in patients with schizophrenia. While the lack of limbic recruitment did not significantly impair simple valence discrimination performance in this clinically stable group, it may impact performance of more demanding tasks.     

抑郁症患者汉语情绪词阈下的Stroop效应事件相关电位

背景：抑郁症患者负性认知偏差与情绪信息加工的关系是一个重要的研究课题。情绪Stroop测验常用于评估情绪加工特点,而情绪词阈下Stroop刺激模式也常用于精神病学临床研究。 目的：本研究采用阈下汉语情绪词Stroop刺激范式来探讨抑郁症患者异常情绪信息加工的事件相关电位(ERP)效应。 设计,时间和地点：随机对照设计,时间为2007年8月至2008年3月,地点在中南大学湘雅二医院。 研究对象：首发抑郁症患者26例,符合DSM-IV抑郁症诊断标准,无脑部疾病、躯体疾病,未进行电休克治疗和抗抑郁药物治疗。健康对照组24例。两组在年龄、性别和教育水平方面无差异,均为右利手。 方法：采用阈下汉语情绪词Stroop刺激范式,要求被试对呈现200ms的红色或蓝色方块进行反应,而汉语情绪词阈下启动刺激为20ms。主要分析行为学和ERP数据。 主要测试指标：反应时和ERP成分的潜伏期和波幅。参照ERP平均波幅图以及其它研究,主要分析N270 (220~300ms)成分和N400 (380~450ms)成分的潜伏期和波幅。 结果：行为数据显示两组正确率之间无显著性差异,抑郁症组反应时比正常对照组延长,尤其是负性词与中性词(p<0.01)。重复测量方差分析表明,N270成分的波幅有词性和电极的主效应(p<0.01)以及词性和电极的交互效应(p<0.05);两组波幅大小顺序均为正性词>负性词>中性词。组别、词性差异波地形图显示差异主要分布在额区和左侧顶颞区。N400成分的波幅有词性和电极的主效应(p<0.01),潜伏期显示电极的主效应(p<0.01)以及电极和组别的交互效应(p<0.01);两组波幅大小顺序均为正性词>负性词>中性词,而且两组之间的三种情绪词波幅之间有显著性差异(p<0.01)。组别、词性差异波地形图显示差异主要分布在左右额区、中央区和左侧顶颞区。 结论：抑郁症患者执行阈下汉语情绪词Stroop刺激作业时表现了异常的情绪信息加工特征,以及对汉语情绪词三种词性进行语义激活时与正常组相比表现为不同的ERP时程效应。研究结果支持我们提出的正负性情绪平行神经模型。     

The emotional paradox: Dissociation between explicit and implicit processing of emotional prosody in schizophrenia

People with schizophrenia show well-replicated deficits on tasks of explicit recognition of emotional prosody. However it remains unclear whether they are still sensitive to the implicit cues of emotional prosody, particularly when they exhibit high levels of social anhedonia. A dual processing model suggesting a dissociation between the neural networks involved in explicit and implicit recognition of emotional prosody has yet to be validated.21 participants with schizophrenia and 21 controls were recruited. In the explicit recognition task, individuals listened to semantically neutral words pronounced with two different emotions and judged their emotional prosody. In the vocal emotional Stroop task, patients and controls listened to words with a positive or negative emotional valence pronounced with congruent or incongruent emotional prosody and judged their emotional content. Patients were also assessed with the Chapman Anhedonia Questionnaire and the Schizophrenic Communication Disorders scale.Individuals with schizophrenia were impaired in their explicit recognition of emotional prosody related to controls. In contrast, they showed a vocal emotional Stroop effect that was identical to controls for reaction time and greater for accuracy: patients were still sensitive to implicit emotional prosody. In addition the vocal emotional Stroop score increased with social anhedonia but was unrelated to communication disorders.Whereas explicit vocal affect recognition is impaired, implicit processing of emotional prosody seems to be preserved in schizophrenia. Our results provide evidence that at a behavioural level, the implicit and explicit processing of emotional prosody can be dissociated. Remediation of emotional prosody recognition in schizophrenia should target cognitive rather than sensory processes.     

The influence of emotional associations on the neural correlates of semantic priming

Emotions influence our everyday life in several ways. With the present study, we wanted to examine the impact of emotional information on neural correlates of semantic priming, a well-established technique to investigate semantic processing. Stimuli were presented with a short SOA of 200 ms as subjects performed a lexical decision task during fMRI measurement. Seven experimental conditions were compared: positive/negative/neutral related, positive/negative/neutral unrelated, nonwords (all words were nouns). Behavioral data revealed a valence specific semantic priming effect (i.e., unrelated > related) only for neutral and positive related word pairs. On a neural level, the comparison of emotional over neutral relations showed activation in left anterior medial frontal cortex, superior frontal gyrus, and posterior cingulate. Interactions for the different relations were located in left anterior part of the medial frontal cortex, cingulate regions, and right hippocampus (positive > neutral + negative) and left posterior part of medial frontal cortex (negative > neutral + positive). The results showed that emotional information have an influence on semantic association processes. While positive and neutral information seem to share a semantic network, negative relations might induce compensatory mechanisms that inhibit the spread of activation between related concepts. The neural correlates highlighted a distributed neural network, primarily involving attention, memory and emotion related processing areas in medial fronto-parietal cortices. The differentiation between anterior (positive) and posterior part (negative) of the medial frontal cortex was linked to the type of affective manipulation with more cognitive demands being involved in the automatic processing of negative information.     

Aberrantly flattened responsivity to emotional pictures in paranoid schizophrenia

To investigate the nature of emotional experience in schizophrenia, we examined emotional responses to affective stimuli. Twenty-one outpatients with schizophrenia (9 paranoid, 12 nonparanoid) and 20 normal controls rated the arousal and valence that they experienced from the presentation of 60 pictures. Schizophrenia patients displayed less emotional responsivity to the positive stimuli and they displayed diverse responsivity to the negative stimuli, which depended upon arousal level. Further analysis, using schizophrenia subtype, indicated that nonparanoid patients reported increased negative responsivity and decreased positive responsivity, regardless of arousal level. However, paranoid schizophrenia patients showed enhanced self-reported experiences of emotion to the low arousing stimuli and diminished responsivity to the high arousing stimuli. This pattern was robust to the negative stimuli. These findings suggest that paranoid schizophrenia patients might suffer from aberrantly flattened responses to negative emotional stimuli, and that this may account for paranoid tendency and secondary social isolation in paranoid schizophrenia.     

Localized task-invariant emotional valence encoding revealed by intracranial recordings

The ability to distinguish between negative, positive and neutral valence is a key part of emotion perception. Emotional valence has conceptual meaning that supersedes any particular type of stimulus, although it is typically captured experimentally in association with particular tasks. We sought to identify neural encoding for task-invariant emotional valence. We evaluated whether high-gamma responses (HGRs) to visually displayed words conveying emotions could be used to decode emotional valence from HGRs to facial expressions. Intracranial electroencephalography was recorded from 14 individuals while they participated in two tasks, one involving reading words with positive, negative, and neutral valence, and the other involving viewing faces with positive, negative, and neutral facial expressions. Quadratic discriminant analysis was used to identify information in the HGR that differentiates the three emotion conditions. A classifier was trained on the emotional valence labels from one task and was cross-validated on data from the same task (within-task classifier) as well as the other task (between-task classifier). Emotional valence could be decoded in the left medial orbitofrontal cortex and middle temporal gyrus, both using within-task classifiers and between-task classifiers. These observations suggest the presence of task-independent emotional valence information in the signals from these regions.     

Neural correlates of positive and negative emotion regulation

The ability to cope adaptively with emotional events by volitionally altering one's emotional reactions is important for psychological and physical health as well as social interaction. Cognitive regulation of emotional responses to aversive events engages prefrontal regions that modulate activity in emotion-processing regions such as the amygdala. However, the neural correlates of the regulation of positive emotions remain largely unexplored. We used event-related functional magnetic resonance imaging to examine the neural correlates of cognitively increasing and decreasing emotional reactions to positive and negative stimuli. Participants viewed negative, positive, and neutral pictures while attempting to increase, decrease, or not alter their emotional reactions. Subjective reactions were assessed via on-line ratings. Consistent with previous studies, increasing negative and positive emotion engaged primarily left-lateralized prefrontal regions, whereas decreasing emotion activated bilateral prefrontal regions. Different activations unique to increasing versus decreasing emotion were observed for positive and negative stimuli: Unique increase-related activations were observed only for positive stimuli, whereas unique decrease-related activations were observed only for negative stimuli. Regulation also modulated activity in the amygdala, a key emotion-processing region. Regulation effects on amygdala activity were larger for positive than for negative stimuli, potentially reflecting a greater malleability of positive emotional reactions. Increasing and decreasing positive and negative emotion can thus increase and decrease subjective reactions and associated amygdala activity in line with regulatory goals, and is associated with different patterns of prefrontal activation as a function of emotional valence and regulatory goal.     

Neural correlates of emotional recognition memory in schizophrenia: effects of valence and arousal

Schizophrenia patients are often impaired in their memory for emotional events compared with healthy subjects. Investigations of the neural correlates of emotional memory in schizophrenia patients are scarce in the literature. The present study aimed to compare cerebral activations in schizophrenia patients and healthy controls during memory retrieval of emotional images that varied in both valence and arousal. In a study with functional magnetic resonance imaging, 37 schizophrenia patients were compared with 37 healthy participants while performing a yes/no recognition paradigm with positive, negative (differing in arousal intensity) and neutral images. Schizophrenia patients performed worse than healthy controls in all experimental conditions. They showed less cerebral activation in limbic and prefrontal regions than controls during retrieval of negatively valenced stimuli, but had a similar pattern of brain activation compared with controls during retrieval of positively valenced stimuli (particularly in the high arousal condition) in the cerebellum, temporal lobe and prefrontal cortex. Both groups demonstrated increased brain activations in the high relative to low arousing conditions. Our results suggest atypical brain function during retrieval of negative pictures, but intact functional circuitry of positive affect during episodic memory retrieval in schizophrenia patients. The arousal data revealed that schizophrenia patients closely resemble the control group at both the behavioral and neurofunctional level.     

Regional cerebral changes and functional connectivity during the observation of negative emotional stimuli in subjects with post-traumatic stress disorder

Patients with post-traumatic stress disorder (PTSD) exhibit exaggerated brain responses to emotionally negative stimuli. Identifying the neural correlates of emotion regulation in these subjects is important for elucidating the neural circuitry involved in emotional dysfunction. The aim of this study was to investigate the functional connectivity between the areas activated during emotional processing of negative stimuli in a sample of individuals affected by PTSD compared to a group of healthy subjects. Ten subjects with PTSD (who survived the L’Aquila 2009 earthquake) and ten healthy controls underwent fMRI during which the participants observed 80 images: 40 pictures with negative emotional valence and 40 neutral (scrambled) stimuli. A higher activation was found in the left posterior (LP) insula for PTSD group and in the ventromedial prefrontal cortex (vmPFC) for the healthy group. Two sets of Granger causality modeling analyses were performed to examine the directed influence from LP-insula and vmPFC to other brain regions. Activity in the vmPFC in the healthy group while observing negative stimuli predicted activity in several subcortical regions and insula, while in the PTSD group the LP-insula exerted a positive directed influence on several cortical regions. The hyperactivation in PTSD subjects of subcortical areas such as the insula would underlie the emotional, social, and relational difficulties of PTSD patients.     

The face and its emotion: right N170 deficits in structural processing and early emotional discrimination in schizophrenic patients and relatives

Previous studies have reported facial emotion recognition impairments in schizophrenic patients, as well as abnormalities in the N170 component of the event-related potential. Current research on schizophrenia highlights the importance of complexly-inherited brain-based deficits. In order to examine the N170 markers of face structural and emotional processing, DSM-IV diagnosed schizophrenia probands (n=13), unaffected first-degree relatives from multiplex families (n=13), and control subjects (n=13) matched by age, gender and educational level, performed a categorization task which involved words and faces with positive and negative valence. The N170 component, while present in relatives and control subjects, was reduced in patients, not only for faces, but also for face-word differences, suggesting a deficit in structural processing of stimuli. Control subjects showed N170 modulation according to the valence of facial stimuli. However, this discrimination effect was found to be reduced both in patients and relatives. This is the first report showing N170 valence deficits in relatives. Our results suggest a generalized deficit affecting the structural encoding of faces in patients, as well as the emotion discrimination both in patients and relatives. Finally, these findings lend support to the notion that cortical markers of facial discrimination can be validly considered as vulnerability markers.     

Emotion disrupts neural activity during selective attention in psychopathy

Dimensions of psychopathy are theorized to be associated with distinct cognitive and emotional abnormalities that may represent unique neurobiological risk factors for the disorder. This hypothesis was investigated by examining whether the psychopathic personality dimensions of fearless-dominance and impulsive-antisociality moderated neural activity and behavioral responses associated with selective attention and emotional processing during an emotion-word Stroop task in 49 adults. As predicted, the dimensions evidenced divergent selective-attention deficits and sensitivity to emotional distraction. Fearless-dominance was associated with disrupted attentional control to positive words, and activation in right superior frontal gyrus mediated the relationship between fearless-dominance and errors to positive words. In contrast, impulsive-antisociality evidenced increased behavioral interference to both positive and negative words and correlated positively with recruitment of regions associated with motivational salience (amygdala, orbitofrontal cortex, insula), emotion regulation (temporal cortex, superior frontal gyrus) and attentional control (dorsal anterior cingulate cortex). Individuals high on both dimensions had increased recruitment of regions related to attentional control (temporal cortex, rostral anterior cingulate cortex), response preparation (pre-/post-central gyri) and motivational value (orbitofrontal cortex) in response to negative words. These findings provide evidence that the psychopathy dimensions represent dual sets of risk factors characterized by divergent dysfunction in cognitive and affective processes.     

Experiential pleasure deficits in the prodrome: A study of emotional experiences in individuals at ultra-high risk for psychosis and recent-onset schizophrenia

BackgroundPrevious studies report deficits in noncurrent but not current pleasure experience in schizophrenia, but little is known about pleasure experiences of the prodrome. This study investigated noncurrent and current pleasure experiences and its relationship with neurocognitive function and self-esteem in ultra-high risk (UHR) for psychosis and recent-onset schizophrenia (ROSPR).MethodsTwenty-four UHR, 25 ROSPR and 42 normal controls completed the physical and social anhedonia scales for noncurrent emotional experience and the laboratory-based assessment of valence and arousal evoked by positive, neutral and negative emotional stimuli for current emotional experience. Relationships of current and noncurrent emotional experience, episodic memory and self-esteem were investigated.ResultsFor ROSPR, noncurrent pleasure, but not current pleasure evoked by positive stimuli, was diminished. Noncurrent anhedonia in ROSPR was related to episodic memory deficits and low self-esteem. In UHR subjects, both noncurrent pleasure and current pleasure to positive and neutral stimuli were diminished. Noncurrent anhedonia in UHR was not associated with episodic memory nor self-esteem. For arousal, ROSPR patients showed higher arousal than UHR subjects to positive stimuli.ConclusionsFindings indicate the presence of experiential hedonic deficits during the prodrome phase. Diminished noncurrent pleasure reports exist in ROSPR, which seems to be associated with cognitive deficits and low self-concept. Future research is needed to probe into further underlying mechanisms.     

Ketamine alters neural processing of facial emotion recognition in healthy men: an fMRI study

Disruption of facial emotion perception occurs in neuropsychiatric disorders where the expression of emotion is dulled or blunted, for example depersonalization disorder and schizophrenia. It has been suggested that, in the clinical context of emotional blunting, there is a shift in the relative contribution of brain regions subserving cognitive and emotional processing. The non-competitive glutamate receptor antagonist ketamine produces such emotional blunting in healthy subjects. Therefore, we hypothesised that in healthy subjects ketamine would elicit neural responses to emotional stimuli which mimicked those reported in depersonalization disorder and schizophrenia. Thus, we predicted that ketamine would produce reduced activity in limbic and visual brain regions involved in emotion processing, and increased activity in dorsal regions of the prefrontal cortex and cingulate gyrus, both associated with cognitive processing and, putatively, with emotion regulation. Measuring BOLD signal change in fMRI, we examined the neural correlates of ketamine-induced emotional blunting in eight young right-handed healthy men receiving an infusion of ketamine or saline placebo while viewing alternating 30 s blocks of faces displaying fear versus neutral expressions. The normal pattern of neural response occurred in limbic and visual cortex to fearful faces during the placebo infusion. Ketamine abolished this: significant BOLD signal change was demonstrated only in left visual cortex. However, with ketamine, neural responses were demonstrated to neutral expressions in visual cortex, cerebellum and left posterior cingulate gyrus. Emotional blunting may be associated with reduced limbic responses to emotional stimuli and a relative increase in the visual cortical response to neutral stimuli.     

Cortical deficits of emotional face processing in adults with ADHD: its relation to social cognition and executive function

Although it has been shown that adults with attention-deficit hyperactivity disorder (ADHD) have impaired social cognition, no previous study has reported the brain correlates of face valence processing. This study looked for behavioral, neuropsychological, and electrophysiological markers of emotion processing for faces (N170) in adult ADHD compared to controls matched by age, gender, educational level, and handedness. We designed an event-related potential (ERP) study based on a dual valence task (DVT), in which faces and words were presented to test the effects of stimulus type (faces, words, or face-word stimuli) and valence (positive versus negative). Individual signatures of cognitive functioning in participants with ADHD and controls were assessed with a comprehensive neuropsychological evaluation, including executive functioning (EF) and theory of mind (ToM). Compared to controls, the adult ADHD group showed deficits in N170 emotion modulation for facial stimuli. These N170 impairments were observed in the absence of any deficit in facial structural processing, suggesting a specific ADHD impairment in early facial emotion modulation. The cortical current density mapping of N170 yielded a main neural source of N170 at posterior section of fusiform gyrus (maximum at left hemisphere for words and right hemisphere for faces and simultaneous stimuli). Neural generators of N170 (fusiform gyrus) were reduced in ADHD. In those patients, N170 emotion processing was associated with performance on an emotional inference ToM task, and N170 from simultaneous stimuli was associated with EF, especially working memory. This is the first report to reveal an adult ADHD-specific impairment in the cortical modulation of emotion for faces and an association between N170 cortical measures and ToM and EF.     

Reduced sustained brain activity during processing of positive emotional stimuli in major depression.

BACKGROUND: This study examines the directionality and temporal specificity of brain activity during sustained processing of emotional stimuli in individuals with current major depressive disorder (MDD) and nondepressed control participants. METHODS: Slow wave (SW) components of the event-related brain potential (ERP) were recorded from 16 control participants and 15 participants with MDD during a working memory task. During the task, individuals were shown a positive, neutral, or negative word and were asked to maintain it in memory for 5 sec. Participants then saw a letter and had to decide whether it was a part of the previously presented word. The ERP components were measured from nine scalp sites (F3, Fz, F4, C3, Cz, C4, P3, Pz, P4) during the encoding of emotional words. RESULTS: Compared with control individuals, MDD participants exhibited decreased brain responses to positive relative to negative or neutral stimuli. This decrease in brain activity during processing of positive information was evident across all sites and SW components. CONCLUSIONS: Our findings suggest that cognitive deficits in MDD may stem from diminished brain responses during processing of positive information and may not be associated with an augmented response to negative stimuli.     

Hemispheric processing of differently valenced and self-relevant attachment words in middle-aged married and separated individuals

The reliance in experimental psychology on testing undergraduate populations with relatively little life experience, and/or ambiguously valenced stimuli with varying degrees of self-relevance, may have contributed to inconsistent findings in the literature on the valence hypothesis. To control for these potential limitations, the current study assessed lateralised lexical decisions for positive and negative attachment words in 40 middle-aged male and female participants. Self-relevance was manipulated in two ways: by testing currently married compared with previously married individuals and by assessing self-relevance ratings individually for each word. Results replicated a left hemisphere advantage for lexical decisions and a processing advantage of emotional over neutral words but did not support the valence hypothesis. Positive attachment words yielded a processing advantage over neutral words in the right hemisphere, while emotional words (irrespective of valence) yielded a processing advantage over neutral words in the left hemisphere. Both self-relevance manipulations were unrelated to lateralised performance. The role of participant sex and age in emotion processing are discussed as potential modulators of the present findings.     

In search of the emotional self: an fMRI study using positive and negative emotional words

OBJECTIVE: The authors used functional magnetic resonance imaging (fMRI) to define the neural regions mediating self-referential processing of emotional stimuli and to explore how these regions are influenced by the emotional valence of the stimulus. METHOD: Ten healthy subjects were presented with words describing positive and negative personality traits during fMRI scanning in three different conditions. In the self-referential processing condition, subjects judged whether they thought each trait described them. In the other-referential processing condition, subjects judged whether the stimulus described a generally desirable trait. In the letter-recognition control condition, subjects indicated whether the word contained a specific target letter. RESULTS: The self-referential condition induced bilateral activation in the dorsomedial prefrontal cortex, whereas the other-referential condition induced activation in lateral prefrontal areas. Activation in the right dorsomedial prefrontal cortex was unique to the self-referential condition regardless of the valence of the words, although positive words produced a more robust activation than did negative words. In the self-referential condition, differences between the processing of positive and negative words were seen in regions outside the medial frontal cortex, with reductions in the insula, temporal and occipital regions, and inferior parietal regions associated with negative words. CONCLUSIONS: A widely distributed network of brain areas contributes to emotional processing. Among these regions, the right dorsomedial prefrontal cortex is one main area mediating self-reference. By providing a personal perspective in the evaluation of emotional stimuli, the right dorsomedial prefrontal cortex may mediate cognitive processes, such as those involved in psychotherapy, that guide self-regulation of emotional experience.