Evidence for modulation of facial emotional processing bias during emotional expression decoding by serotonergic and noradrenergic antidepressants: an event-related potential (ERP) study

Changes in emotion-related EEG components and brain lateralization response to negative emotions in adolescents with nonsuicidal self-injury: An ERP study

Nonsuicidal self-injury (NSSI) is a serious risk behavior in adolescents and is a high risk factor for suicide, while negative emotions can lead to increased NSSI behaviors. In this study, we investigated the altered behavioral performance and neural reactivity of adolescents with NSSI by using a two-choice oddball paradigm when exposed to negative emotional stimuli, and analyzed the brain lateralization effect. Our data indicated that adolescents with NSSI exhibit more pronounced N250, P300, and LPP components during negative emotional face stimulation, as evidenced by a smaller N250 wave amplitude, larger P300 wave amplitude, steeper LPP waveform, and faster fallback baseline; and the presence of brain lateralization responses in both the N250 component and the LPP component. These results suggested that adolescents with NSSI showed significant alterations in cognitive EEG components associated with emotional processing during negative emotional face stimulation, particularly in EEG components representing inhibitory control, and there was a lateralization effect on emotional processing in the brain, with different processing stages and different dominance of the left and right brain.

Attentional Bias Deficits in Adolescent Suicide Attempters During an Emotional Stroop Task: An ERP Study

There is increasing evidence that, in adolescence, attentional bias plays a critical role in the vulnerability for suicidal behaviour. No studies to date have investigated the neurophysiological correlates of attentional bias in adolescent suicidality. The present study uses event-related potentials (ERPs) to investigate such processing in inpatient adolescents admitted for an acute suicide crisis using an Emotional Stroop Task (EST). In this task, participants are asked to name the colour of words varying in emotional valence (positive, negative, neutral, suicide-related). Suicidal individuals are hypothesised to be more preoccupied by the context of the suicide-related stimuli, which may interfere with their ability to perform the colour naming task. Seventeen adolescents with acute suicidal behaviour and 17 age- and gender-matched healthy controls performed an EST while ERPs were recorded. Suicide attempters showed increased reaction times to suicide-related words compared to other emotion categories, while the controls did not. The amplitude of the early posterior negativity (EPN) was not significantly different across groups or emotional valence. A double peak P3 (early-P3 and late-P3) was observed in both groups. Both the early- and late-P3 were significantly reduced in amplitude in the suicide attempter group compared to the control group, regardless of emotional valence. The late-P3 latency was also significantly delayed in the suicide attempters compared to controls. The behavioural findings support the attentional bias theories of suicide attempters and extend these findings to adolescents. Furthermore, large early- and late-P3 provide evidence that cognitive strategies employed by two groups did markedly differ.

Subliminal affective priming effect: Dissociated processes for intense versus normal facial expressions

Positive vs. negative intense-facial expressions are difficult to explicitly distinguish; yet, whether they dissociate when subliminally presented remains unclear. Through three experiments using affective priming paradigms, we assessed how intense facial expressions, when presented briefly (17 ms) and masked, influenced following neutral ambiguous words (Experiment 1) or visible facial expressions (Experiments 2&3). We also compared these results with those of using normal facial expressions as primes in each experiment. All experiments indicated masked affective priming effects (biasing valence judgement of neutral words or facilitating reaction time to faces with the same valence as the prime) in normal facial expression, but not those intense ones. Experiment 3 using event related potentials (ERPs) further revealed that two ERP components N250 and LPP were consistent with behavioral changes in the normal condition (larger when valences of primes and targets were different), but inconsistent in the intense condition. Taken together, our results provided behavioral and neural evidence for distinctive processing between normal and intense facial expressions under masked condition.

Approach and Avoidance Behavior in Female Patients With Borderline Personality Disorder

Objectives

Borderline personality disorder (BPD) is portrayed by unstable relationships, fears of abandonment and heightened sensitivity to social rejection. Research has shown that these characteristics may lead to inappropriate social behavior including altered approach-avoidance behavior. However, it has remained unclear how social exclusion may affect approach-avoidance behavior in patients with BPD.

Design

We assessed social approach-avoidance behavior and the impact of social exclusion in a sample of 38 patients with BPD and 40 healthy control participants.

Methods

We used an explicit joystick-based approach-avoidance task (AAT) after playing a virtual ball-tossing game (Cyberball), which simulates the exclusion of the participant by two other players. In the AAT, participants were required to push or pull emotional stimuli, more specifically happy and angry facial expressions, with either direct or averted gaze direction.

Results

Patients with BPD approached happy stimuli less and showed overall less differential approach-avoidance behavior toward individuals expressing positive or negative facial emotions compared to healthy participants, who showed more approach behavior for happy compared to angry facial expressions. Moreover, borderline symptom severity correlated inversely with the AAT score for happy facial expressions and positively with subjective unpleasantness during social exclusion as well as rejection sensitivity. However, social exclusion did not influence approach-avoidance tendencies.

Conclusion

Patients with BPD showed altered approach-avoidance behavior, which might affect social interactions in the patient’s everyday lives and may therefore impede social interaction.

Configural processing of emotional bodies and faces in patients with attention deficit hyperactivity disorder

Introduction: Attention Deficit Disorder (ADHD) is associated with interpersonal problems and difficulties in inferring other peoples' emotions. Previous research has focused on face processing, mostly in children. Our study investigated configural processing of emotional bodies and faces in adults with ADHD in comparison with healthy controls, analyzing P100, N170 and P250 event-related potentials (ERPs) and relating them to (socio)cognitive functioning. Method: Nineteen patients with ADHD and 25 healthy controls were presented upright and inverted bodies and faces which had to be categorized as neutral, happy or angry while ERPs were recorded. Additionally, sociocognitive and executive functioning was assessed. Results: In ADHD patients relative to controls, recognition of emotions depicted by bodies but not by faces was impaired and P100 amplitudes were enhanced for angry bodies. Furthermore, patients showed enhanced P250 amplitudes in response to both bodies and faces, specifically for happy and neutral emotions. Larger N170 amplitudes to bodies and faces correlated with lower alexithymia scores only in controls, while enhanced P250 amplitudes to both categories were associated with poorer inhibition only in patients. Conclusion: Adults with ADHD show potentially compensatory enhanced semantic processing of emotional bodies and faces, as reflected by increased P250 amplitudes, associated with poorer executive functioning and subtle alterations of emotional and configural processing, as reflected by ERPs.

Attenuated LPP to Emotional Face Stimuli Associated with Parent- and Self-Reported Depression in Children and Adolescents

Individuals diagnosed with a depressive disorder have been found to show reduced reactions to emotional information consistent with the hypothesis of an emotional context insensitivity. However, there are contradictory findings of enhanced reactivity and mood-congruent processing. Electroencephalography (EEG) recordings of the late positive potential (LPP) can display such blunted or enhanced activity. Due to these contradictory findings, there is a need to clarify the role of the LPP in the emergence and presence of depressive disorders especially in children. We used an emotional Go/NoGo task to investigate modulations of the LPP to emotional (fearful, happy, sad) and calm faces in a sample of children and adolescents (age 11;00-14;11) diagnosed with a depressive disorder according to diagnostic parent interviews (K-SADS-PL) (n = 26) compared to a group of age-matched healthy controls (n = 26). LPP positivity was attenuated in children and adolescents with a depressive disorder as well as with higher self-reported depressive symptoms, suggesting reduced reactivity to emotional and calm faces. This is the first study to find generally blunted LPP responses in a clinical sample of depressed youth across reporters. Such dysfunctional modulation of neural activity may represent a potential biomarker for depressive disorders. The results call for further prospective studies investigating the course of the LPP before and after the onset of a depressive disorder in youth.

Neuroticism predicts the impact of serotonin challenges on fear processing in subgenual anterior cingulate cortex

The personality trait neuroticism is associated with increased vulnerability to anxiety and mood disorders, conditions linked with abnormal serotonin neurotransmission and emotional processing. The interaction between neuroticism and serotonin during emotional processing is however not understood. Here we investigate how individual neuroticism scores influence the neural response to negative emotional faces and their sensitivity to serotonergic tone. Twenty healthy participants performed an emotional face task under functional MRI on three occasions: increased serotonin tone following infusion of a selective serotonin reuptake inhibitor (SSRI), decreased serotonin tone following acute tryptophan depletion (ATD) protocol, and no serotonin challenge (control). During the task, participants performed a gender-discrimination task of neutral, fearful or angry facial expressions. Individual variations in neuroticism scores were associated with neural response of subgenual anterior cingulate cortex to fearful facial expressions. The association was however opposite under the two serotoninergic challenges. The fear-related response in this region and individual neuroticism scores correlated negatively during citalopram challenge and positively during ATD. Thus, neuroticism scores were associated with the relative impact of serotonin challenges on fear processing in subgenual anterior cingulate cortex. This finding may link to a neural mechanism for the variable therapeutic effect of SSRI treatment observed in clinical populations.

Dissociation in Rating Negative Facial Emotions between Behavioral Variant Frontotemporal Dementia and Major Depressive Disorder

OBJECTIVE

Features of behavioral variant frontotemporal dementia (bvFTD) such as executive dysfunction, apathy, and impaired empathic abilities are also observed in major depressive disorder (MDD). This may contribute to the reason why early stage bvFTD is often misdiagnosed as MDD. New assessment tools are thus needed to improve early diagnosis of bvFTD. Although emotion processing is affected in bvFTD and MDD, growing evidence indicates that the pattern of emotion processing deficits varies between the two disorders. As such, emotion processing paradigms have substantial potentials to distinguish bvFTD from MDD.

DESIGN AND PARTICIPANTS

The current study compared 25 patients with bvFTD, 21 patients with MDD, 21 patients with Alzheimer disease (AD) dementia, and 31 healthy participants on a novel facial emotion intensity rating task. Stimuli comprised morphed faces from the Ekman and Friesen stimulus set containing faces of each sex with two different degrees of emotion intensity for each of the six basic emotions.

MEASUREMENTS AND RESULTS

Analyses of covariance uncovered a significant dissociation between bvFTD and MDD patients in rating the intensity of negative emotions overall (i.e., bvFTD patients underrated negative emotions overall, whereas MDD patients overrated negative emotions overall compared with healthy participants). In contrast, AD dementia patients rated negative emotions similarly to healthy participants, suggesting no impact of cognitive deficits on rating facial emotions.

CONCLUSIONS

By strongly differentiating bvFTD and MDDpatients through negative facial emotions, this sensitive and short rating task might help improve the early diagnosis of bvFTD.

Effects of psychotropic drugs used in the treatment of anxiety disorders on the recognition of facial expressions of emotion: Critical analysis of literature

Deficits in recognition of facial expressions of emotion (RFEE) play a central role in the manifestation of anxiety disorders (AD). We systematically reviewed the literature to determine effects of drugs used in AD treatment on RFEE, based on outcomes of accuracy rate, reaction time, and intensity. Electronic databases, including Pubmed, PsycINFO, and Scielo, were used without time constraints. Twenty-six clinical/experimental studies on healthy subjects, focusing on 11 drugs, published in English, Portuguese, and Spanish, were selected. We found that increased recognition of happiness was associated with acute use of citalopram, fluoxetine, duloxetine, and reboxetine. Increased and decreased recognition of negative emotions were associated with the use of selective serotonin and/or norepinephrine reuptake inhibitors, respectively. Benzodiazepine favored recognition of negative emotions. Differences in reaction time were rarely observed. Stimuli with distinct emotion intensities produced similar effects. Specific changes occurred in RFEE depending on the drug, its administration route and dose, and emotion valence. Evidences indicate significant effects on emotional processing relevant to clinical practice, particularly in treating patients with emotional disorders.

Neural processing of fearful and happy facial expressions during emotion-relevant and emotion-irrelevant tasks: A fixation-to-feature approach

Research suggests an important role of the eyes and mouth for discriminating facial expressions of emotion. A gaze-contingent procedure was used to test the impact of fixation to facial features on the neural response to fearful, happy and neutral facial expressions in an emotion discrimination (Exp.1) and an oddball detection (Exp.2) task. The N170 was the only eye-sensitive ERP component, and this sensitivity did not vary across facial expressions. In both tasks, compared to neutral faces, responses to happy expressions were seen as early as 100-120ms occipitally, while responses to fearful expressions started around 150ms, on or after the N170, at both occipital and lateral-posterior sites. Analyses of scalp topographies revealed different distributions of these two emotion effects across most of the epoch. Emotion processing interacted with fixation location at different times between tasks. Results suggest a role of both the eyes and mouth in the neural processing of fearful expressions and of the mouth in the processing of happy expressions, before 350ms.

Face and emotion expression processing and the serotonin transporter polymorphism 5-HTTLPR/rs22531

Face cognition, including face identity and facial expression processing, is a crucial component of socio-emotional abilities, characterizing humans as highest developed social beings. However, for these trait domains molecular genetic studies investigating gene-behavior associations based on well-founded phenotype definitions are still rare. We examined the relationship between 5-HTTLPR/rs25531 polymorphisms - related to serotonin-reuptake - and the ability to perceive and recognize faces and emotional expressions in human faces. For this aim we conducted structural equation modeling on data from 230 young adults, obtained by using a comprehensive, multivariate task battery with maximal effort tasks. By additionally modeling fluid intelligence and immediate and delayed memory factors, we aimed to address the discriminant relationships of the 5-HTTLPR/rs25531 polymorphisms with socio-emotional abilities. We found a robust association between the 5-HTTLPR/rs25531 polymorphism and facial emotion perception. Carriers of two long (L) alleles outperformed carriers of one or two S alleles. Weaker associations were present for face identity perception and memory for emotional facial expressions. There was no association between the 5-HTTLPR/rs25531 polymorphism and non-social abilities, demonstrating discriminant validity of the relationships. We discuss the implications and possible neural mechanisms underlying these novel findings.

The Antidepressant Treatment Response Index as a Predictor of Reboxetine Treatment Outcome in Major Depressive Disorder

Biomarkers to predict clinical outcomes early during the treatment of major depressive disorder (MDD) could reduce suffering and improve outcomes. A quantitative electroencephalogram (qEEG) biomarker, the Antidepressant Treatment Response (ATR) index, has been associated with outcomes of treatment with selective serotonin reuptake inhibitor antidepressants in patients with MDD. Here, we report the results of a post hoc analysis initiated to evaluate whether the ATR index may also be associated with reboxetine treatment outcome, given that its putative mechanism of action is via norepinephrine reuptake inhibition (NRI). Twenty-five adults with MDD underwent qEEG studies during open-label treatment with reboxetine at doses of 8 to 10 mg daily for 8 weeks. The ATR index calculated after 1 week of reboxetine treatment was significantly associated with overall Hamilton Depression Rating Scale (HAM-D) improvement at week 8 (r=0.605, P=.001), even after controlling for baseline depression severity (P=.002). The ATR index predicted response (≥50% reduction in HAM-D) with 70.6% sensitivity and 87.5% specificity, and remission (final HAM-D≤7) with 87.5% sensitivity and 64.7% specificity. These results suggest that the ATR index may be a useful biomarker of clinical response during NRI treatment of adults with MDD. Future studies are warranted to investigate further the potential utility of the ATR index as a predictor of noradrenergic antidepressant treatment response.

The electrophysiological effects of the serotonin 1A receptor agonist buspirone in emotional face processing

Emotional face processing is critically modulated by the serotonergic system, and serotonin (5-HT) receptor agonists impair emotional face processing. However, the specific contribution of the 5-HT1A receptor remains poorly understood. Here we investigated the spatiotemporal brain mechanisms underpinning the modulation of emotional face processing induced by buspirone, a partial 5-HT1A receptor agonist. In a psychophysical discrimination of emotional faces task, we observed that the discrimination fearful versus neutral faces were reduced, but not happy versus neutral faces. Electrical neuroimaging analyses were applied to visual evoked potentials elicited by emotional face images, after placebo and buspirone administration. Buspirone modulated response strength (i.e., global field power) in the interval 230-248ms after stimulus onset. Distributed source estimation over this time interval revealed that buspirone decreased the neural activity in the right dorsolateral prefrontal cortex that was evoked by fearful faces. These results indicate temporal and valence-specific effects of buspirone on the neuronal correlates of emotional face processing. Furthermore, the reduced neural activity in the dorsolateral prefrontal cortex in response to fearful faces suggests a reduced attention to fearful faces. Collectively, these findings provide new insights into the role of 5-HT1A receptors in emotional face processing and have implications for affective disorders that are characterized by an increased attention to negative stimuli.

Studying the neurobiology of human social interaction: Making the case for ecological validity

With this commentary we make the case for an increased focus on the ecological validity of the measures used to assess aspects of human social functioning. Impairments in social functioning are seen in many types of psychopathology, negatively affecting the lives of psychiatric patients and those around them. Yet the neurobiology underlying abnormal social interaction remains unclear. As an example of human social neuroscience research with relevance to biological psychiatry and clinical psychopharmacology, this commentary discusses published experimental studies involving manipulation of the human brain serotonin system that included assessments of social behavior. To date, these studies have mostly been laboratory-based and included computer tasks, observations by others, or single-administration self-report measures. Most laboratory measures used so far inform about the role of serotonin in aspects of social interaction, but the relevance for real-life interaction is often unclear. Few studies have used naturalistic assessments in real life. We suggest several laboratory methods with high ecological validity as well as ecological momentary assessment, which involves intensive repeated measures in naturalistic settings. In sum, this commentary intends to stimulate experimental research on the neurobiology of human social interaction as it occurs in real life.

Dissociation of explicit and implicit measures of the behavioral inhibition and activation system in borderline personality disorder

Patients with borderline personality disorder (BPD) suffer from various impairments in emotional functioning such as affective instability, inappropriate anger and unstable relationships. These deficits may influence two fundamental motivational systems, the behavioral inhibition system (BIS) and behavioral activation system (BAS). To investigate behavioral intentions and possible impairments in BPD we applied an implicit joystick task to measure implicit behavioral tendencies in response to facial expressions (happiness, sadness, anger, fear and neutral) in 25 patients with BPD and matched 25 healthy controls (HC). Additionally, we evaluated explicit approach and avoidance reactions to these social stimuli, emotion recognition abilities and subjective behavioral ratings. Our data analysis suggests that, although BPD patients accurately identified facial emotional expressions and reacted to them similarly as HC in the joystick task, they had significantly stronger avoidance tendencies in the rating task, especially for happiness and fear. On top of this they exhibited increased BIS sensitivity and decreased BAS sensitivity in the self-report measures. Possible influences are maladaptive cognitive schemas, high negative affect, insecure attachment style and a negative evaluation bias. The observed dysfunctional avoidance ratings may influence the appraisal of socially relevant stimuli and therefore adds further knowledge on social interaction problems in BPD.

Emotional facial expression processing in depression: data from behavioral and event-related potential studies

Behavioral literature investigating emotional processes in depressive populations (i.e., unipolar and bipolar depression) states that, compared to healthy controls, depressive subjects exhibit disrupted emotional processing, indexed by lower performance and/or delayed response latencies. The development of brain imaging techniques, such as functional magnetic resonance imaging (fMRI), provided the possibility to visualize the brain regions engaged in emotional processes and how they fail to interact in psychiatric diseases. However, fMRI suffers from poor temporal resolution and cognitive function involves various steps and cognitive stages (serially or in parallel) to give rise to a normal performance. Thus, the origin of a behavioral deficit may result from the alteration of a cognitive stage differently situated along the information-processing stream, outlining the importance of access to this dynamic "temporal" information. In this paper, we will illustrate, through depression, the role that should be attributed to cognitive event-related potentials (ERPs). Indeed, owing to their optimal temporal resolution, ERPs can monitor the neural processes engaged in disrupted cognitive function and provide crucial information for its treatment, training of the impaired cognitive functions and guidelines for clinicians in the choice and monitoring of appropriate medication for the patient.

Spatiotemporal brain dynamics of emotional face processing modulations induced by the serotonin 1A/2A receptor agonist psilocybin

Emotional face processing is critically modulated by the serotonergic system. For instance, emotional face processing is impaired by acute psilocybin administration, a serotonin (5-HT) 1A and 2A receptor agonist. However, the spatiotemporal brain mechanisms underlying these modulations are poorly understood. Here, we investigated the spatiotemporal brain dynamics underlying psilocybin-induced modulations during emotional face processing. Electrical neuroimaging analyses were applied to visual evoked potentials in response to emotional faces, following psilocybin and placebo administration. Our results indicate a first time period of strength (i.e., Global Field Power) modulation over the 168-189 ms poststimulus interval, induced by psilocybin. A second time period of strength modulation was identified over the 211-242 ms poststimulus interval. Source estimations over these 2 time periods further revealed decreased activity in response to both neutral and fearful faces within limbic areas, including amygdala and parahippocampal gyrus, and the right temporal cortex over the 168-189 ms interval, and reduced activity in response to happy faces within limbic and right temporo-occipital brain areas over the 211-242 ms interval. Our results indicate a selective and temporally dissociable effect of psilocybin on the neuronal correlates of emotional face processing, consistent with a modulation of the top-down control.

Acute pharmacologically induced shifts in serotonin availability abolish emotion-selective responses to negative face emotions in distinct brain networks

Pharmacological manipulation of serotonin availability can alter the processing of facial expressions of emotion. Using a within-subject design, we measured the effect of serotonin on the brain's response to aversive face emotions with functional MRI while 20 participants judged the gender of neutral, fearful and angry faces. In three separate and counterbalanced sessions, participants received citalopram (CIT) to raise serotonin levels, underwent acute tryptophan depletion (ATD) to lower serotonin, or were studied without pharmacological challenge (Control). An analysis designed to identify distributed brain responses identified two brain networks with modulations of activity related to face emotion and serotonin level. The first network included the left amygdala, bilateral striatum, and fusiform gyri. During the Control session this network responded only to fearful faces; increasing serotonin decreased this response to fear, whereas reducing serotonin enhanced the response of this network to angry faces. The second network involved bilateral amygdala and ventrolateral prefrontal cortex, and these regions also showed increased activity to fear during the Control session. Both drug challenges enhanced the neural response of this set of regions to angry faces, relative to Control, and CIT also enhanced activity for neutral faces. The net effect of these changes in both networks was to abolish the selective response to fearful expressions. These results suggest that a normal level of serotonin is critical for maintaining a differentiated brain response to threatening face emotions. Lower serotonin leads to a broadening of a normally fear-specific response to anger, and higher levels reduce the differentiated brain response to aversive face emotions.

The NMDA antagonist ketamine and the 5-HT agonist psilocybin produce dissociable effects on structural encoding of emotional face expressions

RATIONALE

Both glutamate and serotonin (5-HT) play a key role in the pathophysiology of emotional biases. Recent studies indicate that the glutamate N-methyl-D-aspartate (NMDA) receptor antagonist ketamine and the 5-HT receptor agonist psilocybin are implicated in emotion processing. However, as yet, no study has systematically compared their contribution to emotional biases.

OBJECTIVES

This study used event-related potentials (ERPs) and signal detection theory to compare the effects of the NMDA (via S-ketamine) and 5-HT (via psilocybin) receptor system on non-conscious or conscious emotional face processing biases.

METHODS

S-ketamine or psilocybin was administrated to two groups of healthy subjects in a double-blind within-subject placebo-controlled design. We behaviorally assessed objective thresholds for non-conscious discrimination in all drug conditions. Electrophysiological responses to fearful, happy, and neutral faces were subsequently recorded with the face-specific P100 and N170 ERP.

RESULTS

Both S-ketamine and psilocybin impaired the encoding of fearful faces as expressed by a reduced N170 over parieto-occipital brain regions. In contrast, while S-ketamine also impaired the encoding of happy facial expressions, psilocybin had no effect on the N170 in response to happy faces.

CONCLUSION

This study demonstrates that the NMDA and 5-HT receptor systems differentially contribute to the structural encoding of emotional face expressions as expressed by the N170. These findings suggest that the assessment of early visual evoked responses might allow detecting pharmacologically induced changes in emotional processing biases and thus provides a framework to study the pathophysiology of dysfunctional emotional biases.

Does coffee enriched with chlorogenic acids improve mood and cognition after acute administration in healthy elderly? A pilot study

RATIONALE

Caffeine exerts positive effects on cognitive and behavioral processes, especially in sub-optimal conditions when arousal is low. Apart from caffeine, coffee contains other compounds including the phenolic compounds ferulic acid, caffeic acid, and the chlorogenic acids, which have purported antioxidant properties. The chlorogenic acids are the most abundant family of compounds found in coffee, yet their effects on cognition and mood have not been investigated.

OBJECTIVES

This study aims to ascertain whether a coffee rich in chlorogenic acid modulates brain function.

METHODS

The present pilot study examined the acute effects of decaffeinated coffee with regular chlorogenic acid content and decaffeinated coffee with high chlorogenic acid content on mood and cognitive processes, as measured by behavioral tasks and event-related potentials (ERPs). Performance and ERP responses to a battery of cognitive tasks were recorded at baseline and following the equivalent of three cups of coffee in a randomized, double-blind, crossover study of 39 healthy older participants.

RESULTS

Compared with the decaffeinated coffee with regular chlorogenic acid and placebo, caffeinated coffee showed a robust positive effect on higher-level mood and attention processes. To a lesser extent, the decaffeinated coffee high in chlorogenic acid also improved some mood and behavioral measures, relative to regular decaffeinated coffee.

CONCLUSIONS

Our pilot results suggest that non-caffeine compounds in coffee such as the chlorogenic acids may be capable of exerting some acute behavioral effects, thus warranting further investigation.

Serotonin at the level of the amygdala and orbitofrontal cortex modulates distinct aspects of positive emotion in primates

Impaired top-down regulation of the amygdala, and its modulation by serotonin (5-HT), is strongly implicated in the dysregulation of negative emotion that characterizes a number of affective disorders. However, the contribution of these mechanisms to the regulation of positive emotion is not well understood. This study investigated the role of 5-HT within the amygdala and the orbitofrontal cortex (OFC), on the expression of appetitive Pavlovian conditioned emotional responses and their reversal in a primate, the common marmoset. Its effects were compared to those of the amygdala itself. Having developed conditioned autonomic and behavioural responses to an appetitive cue prior to surgery, marmosets with excitotoxic amygdala lesions failed to display such conditioned autonomic arousal at retention, but still displayed intact cue-directed conditioned behaviours. In contrast, 5,7-DHT infusions into the amygdala, reducing extracellular 5-HT levels, selectively enhanced the expression of appetitive conditioned behaviour at retention. Similar infusions into the OFC, producing marked reductions in post-mortem 5-HT tissue levels, had no overall effect on autonomic or behavioural responses, either at retention or during reversal learning, but caused an uncoupling of these responses, thereby fractionating emotional output. These data demonstrate the critical role of the amygdala in the expression of appetitive autonomic conditioning, and the region-selective contribution of 5-HT in the amygdala and OFC, respectively, to the expression of conditioned behaviour and the overall coordination of the emotional response. They provide insight into the neurochemical mechanisms underlying the regulation of positive emotional responses, advancing our understanding of the neural basis of pathologically dysregulated emotion.

Beta receptor-mediated modulation of the late positive potential in humans

RATIONALE

Electrophysiological studies have identified a scalp potential, the late positive potential (LPP), which is modulated by the emotional intensity of observed stimuli. Previous work has shown that the LPP reflects the modulation of activity in extrastriate visual cortical structures, but little is known about the source of that modulation.

OBJECTIVES

The present study investigated whether beta-adrenergic receptors are involved in the generation of the LPP.

METHODS

We used a genetic individual differences approach (experiment 1) and a pharmacological manipulation (experiment 2) to test the hypothesis that the LPP is modulated by the activation of β-adrenergic receptors.

RESULTS

In experiment 1, we found that LPP amplitude depends on allelic variation in the β1-receptor gene polymorphism. In experiment 2, we found that LPP amplitude was modulated by the β-blocker propranolol in a direction dependent on subjects' level of trait anxiety: In participants with lower trait anxiety, propranolol led to a (nonsignificant) decrease in the LPP modulation; in participants with higher trait anxiety, propranolol increased the emotion-related LPP modulation.

CONCLUSIONS

These results provide initial support for the hypothesis that the LPP reflects the downstream effects, in visual cortical areas, of β-receptor-mediated activation of the amygdala.

The dynamic allocation of attention to emotion: simultaneous and independent evidence from the late positive potential and steady state visual evoked potentials

Emotional stimuli capture and hold attention without explicit instruction. The late positive potential (LPP) component of the event related potential can be used to track motivated attention toward emotional stimuli, and is larger for emotional compared to neutral pictures. In the frequency domain, the steady state visual evoked potential (ssVEP) has also been used to track attention to stimuli flickering at a particular frequency. Like the LPP, the ssVEP is also larger for emotional compared to neutral pictures. Prior work suggests that both the LPP and ssVEP are sensitive to "top-down" manipulations of attention, however the LPP and ssVEP have not previously been examined using the same attentional manipulation in the same participants. In the present study, LPP and ssVEP amplitudes were simultaneously elicited by unpleasant and neutral pictures. Partway through picture presentation, participants' attention was directed toward an arousing or non-arousing region of unpleasant pictures. In line with prior work, the LPP was reduced when attention was directed toward non-arousing compared to arousing regions of unpleasant pictures; similar results were observed for the ssVEP. Thus, both electrocortical measures index affective salience and are sensitive to directed (here: spatial) attention. Variation in the LPP and ssVEP was unrelated, suggesting that these measures are not redundant with each other and may capture different neurophysiological aspects of affective stimulus processing and attention.

Differential modulation of emotion processing brain regions by noradrenergic and serotonergic antidepressants

RATIONALE

Most widely used antidepressant drugs affect the serotonergic and noradrenergic pathways. However, there are currently no neurobiological criteria for selecting between these targets and predicting the treatment response in individual depressed patients.

OBJECTIVES

The current study is aimed at differentiating brain regions known to be pathophysiologically and functionally involved in depression-related emotion processing with respect to their susceptibility to serotonergic and noradrenergic modulation.

METHODS

In a single-blind pseudo-randomized crossover study, 16 healthy subjects (out of 21 enrolled) were included in analysis after ingesting a single dose of citalopram (a selective serotonin-reuptake inhibitor, 40 mg), reboxetine (a selective noradrenaline-reuptake inhibitor, 8 mg), or placebo at three time points prior to functional magnetic resonance imaging (fMRI). During fMRI, subjects anticipated and subsequently viewed emotional pictures. Effects of serotonergic and noradrenergic modulation versus placebo on brain activity during the perception of negative pictures were analyzed with a repeated measures ANOVA in the whole brain and in specific regions of interest relevant to depression.

RESULTS

Noradrenergic modulation by reboxetine increased brain activity in the thalamus, right dorsolateral prefrontal cortex and occipital regions during the perception of negative emotional stimuli. Citalopram primarily affected the ventrolateral prefrontal cortical regions.

CONCLUSION

The brain regions involved in the processing of negative emotional stimuli were differentially modulated by selective noradrenergic and serotonergic drugs: thalamic activity was increased by reboxetine, whereas citalopram primarily affected ventrolateral prefrontal regions. Thus, dysfunction in these regions, which could be identified in depressed patients, may predict treatment responses to either noradrenergic or serotonergic antidepressants.

Superior 'theory of mind' in borderline personality disorder: an analysis of interaction behavior in a virtual trust game

To gain further insight into interpersonal dysfunction in Borderline Personality Disorder (BPD) we investigated the effects of emotional cues and the fairness of a social partner on the ability to infer other peoples' intentions in a virtual social exchange. 30 BPD patients and 30 nonpatients were asked to play a multiround trust game with four virtual trustees. The trustees varied in regard to fairness and presence of emotional facial cues which were both linked to repayment ratio. BPD patients adjusted their investment to the fairness of their partner. In contrast, nonpatients disregarded the trustees' fairness in the presence of emotional facial expressions. Both groups performed equally in an emotion recognition task and assessed the trustees' fairness comparably. When the unfair trustee provided emotional cues, BPD patients assessed their own behavior as more fair, while the lack of cues led patients to assess their own behavior as unfair. BPD patients are superior in the attribution of mental states to interaction partners when emotional cues are present. While the emotional expressions of a partner dominated the exchange behavior in nonpatients, BPD patients used the objective fairness of their social counterparts to guide their own behavior despite the existence of emotional cues.

The modification of attentional bias to emotional information: A review of the techniques, mechanisms, and relevance to emotional disorders

A negative bias in the deployment of attention to emotional stimuli is commonly found in both anxiety and depression. Recent work has highlighted that such biases are causally related to emotional vulnerability, suggesting that interventions that ameliorate them may be therapeutic. Here, we review the evidence that attentional bias can be modified using both pharmacological and psychological interventions. We highlight the behavioral and neuroimaging studies that suggest that these interventions impact upon attention via alteration of distinct neural mechanisms. Specifically, pharmacological interventions appear to influence the initial deployment of attention via an effect on the amygdala-based stimulus appraisal system, whereas psychological interventions influence attention at later time points and may alter activity in the lateral prefrontal cortex. Finally, we suggest a conceptual framework that embraces both pharmacological and psychological approaches and consider the possible implications of this work for future research and treatment development.

Social anxiety disorder women easily recognize fearfull, sad and happy faces: the influence of gender

BACKGROUND

It has been suggested that individuals with social anxiety disorder (SAD) are exaggeratedly concerned about approval and disapproval by others. Therefore, we assessed the recognition of facial expressions by individuals with SAD, in an attempt to overcome the limitations of previous studies.

METHODS

The sample was formed by 231 individuals (78 SAD patients and 153 healthy controls). All individuals were treatment naïve, aged 18-30 years and with similar socioeconomic level. Participants judged which emotion (happiness, sadness, disgust, anger, fear, and surprise) was presented in the facial expression of stimuli displayed on a computer screen. The stimuli were manipulated in order to depict different emotional intensities, with the initial image being a neutral face (0%) and, as the individual moved on across images, the expressions increased their emotional intensity until reaching the total emotion (100%). The time, accuracy, and intensity necessary to perform judgments were evaluated.

RESULTS

The groups did not show statistically significant differences in respect to the number of correct judgments or to the time necessary to respond. However, women with SAD required less emotional intensity to recognize faces displaying fear (p=0.002), sadness (p=0.033) and happiness (p=0.002), with no significant differences for the other emotions or men with SAD.

CONCLUSIONS

The findings suggest that women with SAD are hypersensitive to threat-related and approval-related social cues. Future studies investigating the neural basis of the impaired processing of facial emotion in SAD using functional neuroimaging would be desirable and opportune.