Amygdala activation to sad pictures during high-field (4 tesla) functional magnetic resonance imaging

Trimodal brain imaging: A novel approach for simultaneous investigation of human brain function

While advancements have improved the extent to which individual brain imaging approaches capture information regarding spatial or temporal dynamics of brain activity, the connections between these aspects and their relation to psychological functioning remain only partially understood. Acquisition and integration across multiple brain imaging modalities allows for the possible clarification of these connections. The present review provides an overview of three complementary modalities - functional magnetic resonance imaging (fMRI), electroencephalography/event-related potentials (EEG/ERP), and event-related optical signals (EROS) - and discusses progress and considerations for each modality, along with a summary of a novel protocol for acquiring them simultaneously. Initial evidence points to the feasibility of acquiring and integrating multiple measures of brain function that allows for addressing questions in ways not otherwise possible using traditional approaches. Simultaneous trimodal brain imaging in humans provides new possibilities for clarifying spatiotemporal dynamics of brain activity and for identifying multifaceted associations with measures of individual differences and important health outcomes.

Subcortical contributions to salience network functioning during negative emotional processing

Core regions of the salience network (SN), including the anterior insula (aINS) and dorsal anterior cingulate cortex (dACC), coordinate rapid adaptive changes in attentional and autonomic processes in response to negative emotional events. In doing so, the SN incorporates bottom-up signals from subcortical brain regions, such as the amygdala and periaqueductal gray (PAG). However, the precise influence of these subcortical regions is not well understood. Using ultra-high field 7-Tesla functional magnetic resonance imaging, this study investigated the bottom-up interactions of the amygdala and PAG with the SN during negative emotional salience processing. Thirty-seven healthy participants completed an emotional oddball paradigm designed to elicit a salient negative emotional response via the presentation of random, task-irrelevant negative emotional images. Negative emotional processing was associated with prominent activation in the SN, spanning the amygdala, PAG, aINS, and dACC. Consistent with previous research, analysis using dynamic causal modelling revealed an excitatory influence from the amygdala to the aINS, dACC, and PAG. In contrast, the PAG showed an inhibitory influence on amygdala, aINS and dACC activity. Our findings suggest that the amygdala may amplify the processing of negative emotional stimuli in the SN to enable upstream access to attentional resources. In comparison, the inhibitory influence of the PAG possibly reflects its involvement in modulating sympathetic-parasympathetic autonomic arousal mediated by the SN. This PAG-mediated effect may be driven by amygdala input and facilitate bottom-up processing of negative emotional stimuli. Overall, our results show that the amygdala and PAG modulate divergent functions of the SN during negative emotional processing.

Amygdala-pons connectivity is hyperactive and associated with symptom severity in depression

Knowledge of the neural underpinnings of processing sad information and how it differs in people with depression could elucidate the neural mechanisms perpetuating sad mood in depression. Here, we conduct a 7 T fMRI study to delineate the neural correlates involved only in processing sad information, including pons, amygdala, and corticolimbic regions. We then conduct a 3 T fMRI study to examine the resting-state connectivity in another sample of people with and without depression. Only clinically depressed people demonstrate hyperactive amygdala–pons connectivity. Furthermore, this connectivity is related to depression symptom severity and is a significant indicator of depression. We speculate that visual sad information reinforces depressed mood and stimulates the pons, strengthening the amygdala–pons connectivity. The relationship between this connectivity and depressive symptom severity suggests that guiding one’s visual attention and processing of sad information may benefit mood regulation.

A study on patients with major depressive disorder (MDD) suggests that a specific sadness-processing connection between the amygdala and pons appears to be dysfunctional among people with MDD and associated with severity of depression.

How much Fear? Exploring the Role of Integral Emotions on Stated Preferences for Wildlife Conservation

Scientific evidence suggests that emotions affect actual human decision-making, particularly in highly emotionally situations such as human-wildlife interactions. In this study we assess the role of fear on preferences for wildlife conservation, using a discrete choice experiment. The sample was split into two treatment groups and a control. In the treatment groups the emotion of fear towards wildlife was manipulated using two different pictures of a wolf, one fearful and one reassuring, which were presented to respondents during the experiment. Results were different for the two treatments. The assurance treatment lead to higher preferences and willingness to pay for the wolf, compared to the fear treatment and the control, for several population sizes. On the other hand, the impact of the fear treatment was lower than expected and only significant for large populations of wolves, in excess of 50 specimen. Overall, the study suggests that emotional choices may represent a source of concern for the assessment of stable preferences. The impact of emotional choices is likely to be greater in situations where a wildlife-related topic is highly emphasized, positively or negatively, by social networks, mass media, and opinion leaders. When stated preferences towards wildlife are affected by the emotional state of fear due to contextual external stimuli, welfare analysis does not reflect stable individual preferences and may lead to sub-optimal conservation policies. Therefore, while more research is recommended for a more accurate assessment, it is advised to control the decision context during surveys for potential emotional choices.

Decreased Cortical Folding of the Fusiform Gyrus and Its Hypoconnectivity with Sensorimotor Areas in Major Depressive Disorder

BACKGROUND

Neuroimaging studies have revealed abnormal cortical folding pattern and disruptive functional connectivity in major depressive disorder (MDD). Combining structure and function in the same population may further our understanding of the neuropathological mechanisms of MDD.

METHOD

Sixty-two patients with MDD and 61 healthy controls (HCs) underwent structural and resting-state functional magnetic resonance imaging (MRI). Group differences in the cortical folding (measured by local gyrification index (LGI)) were analyzed in FreeSurfer. Taking the brain regions with significant group differences in LGI as seed regions, the resting-state functional connectivity analysis was further conducted to explore the corresponding functional connectivity alterations.

RESULTS

Comparing with HCs, patients with MDD showed significantly decreased LGI in the right fusiform gyrus (cohen's d = 0.70). In the seed-based functional connectivity analysis, we found that compared with HCs, patients with MDD showed decreased functional connections between the right fusiform gyrus with sensorimotor areas (precentral and postcentral gyrus) (cohen's d = 1.32) and right superior temporal gyrus (cohen's d = 0.94).

LIMITATIONS

Main limitations are the relatively small sample size and the cross-sectional study design.

CONCLUSION

Decreased LGI in the right fusiform gyrus, as well as decreased functional connectivity between the right fusiform gyrus and the sensorimotor area and right superior temporal gyrus, appears to play a role in the pathophysiology of MDD.

Proof-of-concept evidence for trimodal simultaneous investigation of human brain function

The link between spatial (where) and temporal (when) aspects of the neural correlates of most psychological phenomena is not clear. Elucidation of this relation, which is crucial to fully understand human brain function, requires integration across multiple brain imaging modalities and cognitive tasks that reliably modulate the engagement of the brain systems of interest. By overcoming the methodological challenges posed by simultaneous recordings, the present report provides proof‐of‐concept evidence for a novel approach using three complementary imaging modalities: functional magnetic resonance imaging (fMRI), event‐related potentials (ERPs), and event‐related optical signals (EROS). Using the emotional oddball task, a paradigm that taps into both cognitive and affective aspects of processing, we show the feasibility of capturing converging and complementary measures of brain function that are not currently attainable using traditional unimodal or other multimodal approaches. This opens up unprecedented possibilities to clarify spatiotemporal integration of brain function.

Facial expression recognition: A meta-analytic review of theoretical models and neuroimaging evidence

Discrimination of facial expressions is an elementary function of the human brain. While the way emotions are represented in the brain has long been debated, common and specific neural representations in recognition of facial expressions are also complicated. To examine brain organizations and asymmetry on discrete and dimensional facial emotions, we conducted an activation likelihood estimation meta-analysis and meta-analytic connectivity modelling on 141 studies with a total of 3138 participants. We found consistent engagement of the amygdala and a common set of brain networks across discrete and dimensional emotions. The left-hemisphere dominance of the amygdala and AI across categories of facial expression, but category-specific lateralization of the vmPFC, suggesting a flexibly asymmetrical neural representations of facial expression recognition. These results converge to characteristic activation and connectivity patterns across discrete and dimensional emotion categories in recognition of facial expressions. Our findings provide the first quantitatively meta-analytic brain network-based evidence supportive of the psychological constructionist hypothesis in facial expression recognition.

Differences in attentional control and white matter microstructure in adolescents with attentional, affective, and behavioral disorders

Adolescence is a critical time of physiological, cognitive, and social development. It is also a time of increased risk-taking and vulnerability for psychopathology. White matter (WM) changes during adolescence have been better elucidated in the last decade, but how WM is impacted by psychopathology during this time remains unclear. Here, we examined the link between WM microstructure and psychopathology during adolescence. Twenty youth diagnosed with affective, attentional, and behavioral disorders (clinical sample), and 20 age-matched controls were recruited to examine group differences in WM microstructure, attentional control, and the link between them. The main results showed that clinical sample had relatively lower attentional control and fractional anisotropy (FA) in WM throughout the brain: two association tracts were identified, and many differences were found in areas rich in callosal and projection fibers. Moreover, increased FA was positively associated with attention performance in the clinical sample in structures supporting ventral WM pathways, whereas a similar link was identified in controls in dorsal WM association fibers. Overall, these results support a model of general impairment in WM microstructure combined with reliance on altered, perhaps less efficient, pathways for attentional control in youth with affective, attentional, and behavioral disorders.

Amygdala Functional Connectivity Features in Grief: A Pilot Longitudinal Study

OBJECTIVE

Acute grief, in an important minority of older adults, can become protracted, intense, and debilitating, leading to the development of complicated grief (CG). However, the neurobiologic mechanisms underlying a maladaptive grief response after an attachment loss are unknown. The current study aimed to examine the amygdala brain network features that cross-sectionally explain the symptom variance and longitudinally relate to grief symptom trajectories after an attachment loss.

METHODS

Baseline amygdala functional connectivity (Fc) was assessed using a seed-based resting-state functional magnetic resonance imaging method in 35 adults who were within 1-year after death of a loved one and 21 healthy comparison (HC) participants. Magnetic resonance imaging scans were obtained at baseline, and clinical assessments, including the inventory of complicated grief (ICG) were completed at weeks 0, 8, 16, and 26 (endpoint).

RESULTS

Relative to HC participants, grief participants showed increased amygdala Fc in the posterior default mode (bilateral medial temporal lobes and left precuneus) and thalamus. Amygdala Fc in the default mode and ventral affective regions positively correlated with ICG scores at baseline. Furthermore, increased baseline amygdala functional connections with the dorsal frontal executive control and salience network regions correlated with worsening ICG scores over time. These longitudinal findings persisted after controlling for covariates, including baseline depressive and anxiety symptoms.

CONCLUSION

These results provide novel preliminary evidence suggesting amygdala-based brain network measures to cross-sectionally explain symptom variance and longitudinally correlate with grief symptom trajectories in grievers. Amygdala brain network function measures may have the potential to serve as biomarkers of CG.

Integration of spatio-temporal dynamics in emotion-cognition interactions: A simultaneous fMRI-ERP investigation using the emotional oddball task

Although a large corpus of evidence has identified brain regions and networks involved in emotion-cognition interactions, it remains unclear how spatial and temporal dynamics of the mechanisms by which emotion interfaces with cognition are integrated. Capitalizing on multi-modal brain imaging approaches, we used simultaneous functional magnetic resonance imaging (fMRI) and event-related potential (ERP) recordings, to investigate the link between spatial and temporal aspects of processing in an emotional oddball task, and in relation to personality measures reflecting basic affective responses and emotion control. First, fMRI captured expected dorso-ventral dissociations, with greater response to targets in regions of dorsal brain networks (e.g., dorsolateral prefrontal cortex) and to emotional distracters in regions of ventral networks (e.g., ventrolateral prefrontal cortex, vlPFC). Also, ERP responses to targets were associated with a prominent P300, and responses to distracters with the late positive potential (LPP). Second, providing evidence for spatio-temporal integration of brain signals, ERP-informed fMRI analyses showed a link between LPP amplitude at parietal electrodes and the fMRI signal in the vlPFC, to emotional distraction. Third, regarding the link to personality measures, increased emotional arousability and attentional impulsiveness was associated with greater LPP differences between negative distracters and targets and enhanced response to negative distracters in the amygdala, respectively. Furthermore, we identified opposing relations between responses to emotional distraction and individual scores for cognitive reappraisal and self-control impulsiveness in posterior vlPFC. This suggests a greater engagement of this region in participants with reduced tendencies to employ reappraisal as a coping strategy and those with reduced ability to control impulsive responses during emotional distraction. Together, supporting the feasibility of integrating multi-dimensional approaches to clarify neural mechanisms of emotion-cognition interactions, these results point to convergence and complementarity between measures that differentially capture spatio-temporal dynamics of brain activity, and their associations with measures of individual differences in affective responses and control.

Schizotypal Traits are Linked to Dopamine-Induced Striato-Cortical Decoupling: A Randomized Double-Blind Placebo-Controlled Study

The dopamine hypothesis of schizophrenia implies that alterations in the dopamine system cause functional abnormalities in the brain that may converge to aberrant salience attribution and eventually lead to psychosis. Indeed, widespread brain disconnectivity across the psychotic spectrum has been revealed by resting-state functional magnetic resonance imaging (rs-fMRI). However, the dopaminergic involvement in intrinsic functional connectivity (iFC) and its putative relationship to the development of psychotic spectrum disorders remains partly unclear-in particular at the low-end of the psychosis continuum. Therefore, we investigated dopamine-induced changes in striatal iFC and their modulation by psychometrically assessed schizotypy. Our randomized, double-blind placebo-controlled study design included 54 healthy, right-handed male participants. Each participant was assessed with the Schizotypal Personality Questionnaire (SPQ) and underwent 10 minutes of rs-fMRI scanning. Participants then received either a placebo or 200 mg of L-DOPA, a dopamine precursor. We analyzed iFC of 6 striatal seeds that are known to evoke modulation of dopamine-related networks. The main effect of L-DOPA was a significant functional decoupling from the right ventral caudate to both occipital fusiform gyri. This dopamine-induced decoupling emerged primarily in participants with low SPQ scores, while participants with high positive SPQ scores showed decoupling indifferently of the L-DOPA challenge. Taken together, these findings demonstrate that schizotypal traits may be the result of dopamine-induced striato-occipital decoupling.

Resting state functional connectivity predictors of treatment response to electroconvulsive therapy in depression

There is increasing focus on use of resting-state functional connectivity (RSFC) analyses to subtype depression and to predict treatment response. To date, identification of RSFC patterns associated with response to electroconvulsive therapy (ECT) remain limited, and focused on interactions between dorsal prefrontal and regions of the limbic or default-mode networks. Deficits in visual processing are reported in depression, however, RSFC with or within the visual network have not been explored in recent models of depression. Here, we support prior studies showing in a sample of 18 patients with depression that connectivity between dorsal prefrontal and regions of the limbic and default-mode networks serves as a significant predictor. In addition, however, we demonstrate that including visual connectivity measures greatly increases predictive power of the RSFC algorithm (>80% accuracy of remission). These exploratory results encourage further investigation into visual dysfunction in depression, and use of RSFC algorithms incorporating the visual network in prediction of response to both ECT and transcranial magnetic stimulation (TMS), offering a new framework for the development of RSFC-guided TMS interventions in depression.

Brain Activity and Network Interactions Linked to Valence-Related Differences in the Impact of Emotional Distraction

Previous investigations showed that the impact of negative distraction on cognitive processing is linked to increased activation in a ventral affective system (VAS) and simultaneous deactivation in a dorsal executive system (DES). However, less is known about the influences of positive valence and different arousal levels on these effects. FMRI data were recorded while participants performed a working memory (WM) task, with positive and negative pictures presented as distracters during the delay between the memoranda and probes. First, positive distraction had reduced impact on WM performance, compared with negative distraction. Second, fMRI results identified valence-specific effects in DES regions and overlapping arousal and valence effects in VAS regions, suggesting increased impact of negative distraction and enhanced engagement of coping mechanisms for positive distraction. Third, a valence-related rostro-caudal dissociation was identified in medial frontal regions associated with the default-mode network (DMN). Finally, these DMN regions showed increased functional connectivity with DES regions for negative compared with positive distraction. Overall, these findings suggest that, while both positive and negative distraction engage partly similar arousal-dependent mechanisms, their differential impact on WM performance is linked to dissociations in the engagement of, and coupling between, regions associated with emotion processing and higher lever cognitive control.

Noncontact measurement of emotional and physiological changes in heart rate from a webcam

Heart rate, measured in beats per minute, can be used as an index of an individual's physiological state. Each time the heart beats, blood is expelled and travels through the body. This blood flow can be detected in the face using a standard webcam that is able to pick up subtle changes in color that cannot be seen by the naked eye. Due to the light absorption spectrum of blood, we are able to detect differences in the amount of light absorbed by the blood traveling just below the skin (i.e., photoplethysmography). By modulating emotional and physiological stress-that is, viewing arousing images and sitting versus standing, respectively-to elicit changes in heart rate, we explored the feasibility of using a webcam as a psychophysiological measurement of autonomic activity. We found a high level of agreement between established physiological measures, electrocardiogram, and blood pulse oximetry, and heart rate estimates obtained from the webcam. We thus suggest webcams can be used as a noninvasive and readily available method for measuring psychophysiological changes, easily integrated into existing stimulus presentation software and hardware setups.

Emotional Oddball: A Review on Variants, Results, and Mechanisms

It is of the utmost importance for an organism to rapidly detect and react to changes in its environment. The oddball paradigm has repeatedly been used to explore the underlying cognitive and neurophysiological components of change detection. It is also used to investigate the special role of emotional content in perception and attention (emotional oddball paradigm; EOP). In this article, the EOP is systematically reviewed. The EOP is, for instance, used as a tool to address questions as to what degree emotional deviant stimuli trigger orientation reactions, which role the emotional context plays in the processing of deviant information, and how the processing of emotional deviant information differs interindividually (including clinical populations). Two main variants with regard to the emotionality of standards and deviants are defined. Most of the identified EOP studies report EEG data but an overview of behavioral data is also provided in this review. We integrate evidence from 99 EOP experiments and shape the EOP's theoretical background under the consideration of other paradigms’ mechanisms and theories.

Whole-brain resting-state functional connectivity identified major depressive disorder: A multivariate pattern analysis in two independent samples

BACKGROUND

there has been a recent increase in the use of connectome-based multivariate pattern analysis (MVPA) of resting-state functional magnetic resonance imaging (fMRI) data aimed at distinguishing patients with major depressive disorder (MDD) from healthy controls (HCs). However, the validity of this method needs to be confirmed in independent samples.

METHOD

we used resting-state fMRI to explore whole-brain functional connectivity (FC) patterns characteristic of MDD and to confirm the effectiveness of MVPA in distinguishing MDD versus HC groups in two independent samples. The first sample set included 29 MDD patients and 33 HCs and second sample set included 46 MDD patients and 57 HCs.

RESULTS

for the first sample, we obtained a correct classification rate of 91.9% with a sensitivity of 89.6% and specificity of 93.9%. For the second sample, we observed a correct classification rate of 86.4% with a sensitivity of 84.8% and specificity of 87.7%. With both samples, we found that the majority of consensus FCs used for MDD identification were located in the salience network, default mode network, the cerebellum, visual cortical areas, and the affective network.

LIMITATION

we did not analyze potential structural differences between the groups.

CONCLUSION

results suggest that whole-brain FC patterns can be used to differentiate depressed patients from HCs and provide evidence for the potential use of connectome-based MVPA as a complementary tool in the clinical diagnosis of MDD.

Task difficulty modulates brain activation in the emotional oddball task

Previous functional magnetic resonance imaging (fMRI) studies have reported that task-irrelevant, emotionally salient events can disrupt target discrimination, particularly when attentional demands are low, while others demonstrate alterations in the distracting effects of emotion in behavior and neural activation in the context of attention-demanding tasks. We used fMRI, in conjunction with an emotional oddball task, at different levels of target discrimination difficulty, to investigate the effects of emotional distractors on the detection of subsequent targets. In addition, we distinguished different behavioral components of target detection representing decisional, nondecisional, and response criterion processes. Results indicated that increasing target discrimination difficulty led to increased time required for both the decisional and nondecisional components of the detection response, as well as to increased target-related neural activation in frontoparietal regions. The emotional distractors were associated with activation in ventral occipital and frontal regions and dorsal frontal regions, but this activation was attenuated with increased difficulty. Emotional distraction did not alter the behavioral measures of target detection, but did lead to increased target-related frontoparietal activation for targets following emotional images as compared to those following neutral images. This latter effect varied with target discrimination difficulty, with an increased influence of the emotional distractors on subsequent target-related frontoparietal activation in the more difficult discrimination condition. This influence of emotional distraction was in addition associated specifically with the decisional component of target detection. These findings indicate that emotion-cognition interactions, in the emotional oddball task, vary depending on the difficulty of the target discrimination and the associated limitations on processing resources.

Differential microstructural and morphological abnormalities in mild cognitive impairment and Alzheimer's disease: Evidence from cortical and deep gray matter

One aim of this study is to use non-Gaussian diffusion kurtosis imaging (DKI) for capturing microstructural abnormalities in gray matter of Alzheimer's disease (AD). The other aim is to compare DKI metrics against thickness of cortical gray matter and volume of deep gray matter, respectively. A cohort of 18 patients with AD, 18 patients with amnestic mild cognitive impairment (MCI), and 18 normal controls underwent morphological and DKI MR imaging. Images were investigated using regions-of-interest-based analyses for deep gray matter and vertex-wise analyses for cortical gray matter. In deep gray matter, more regions showed DKI parametric abnormalities than atrophies at the early MCI stage. Mean kurtosis (MK) exhibited the largest number of significant abnormalities among all DKI metrics. At the later AD stage, diffusional abnormalities were observed in fewer regions than atrophies. In cortical gray matter, abnormalities in thickness were mainly in the medial and lateral temporal lobes, which fit the locations of known early pathological changes. Microstructural abnormalities were predominantly in the parietal and even frontal lobes, which fit the locations of known late pathological changes. In conclusion, MK can complement conventional diffusion metrics for detecting microstructural changes, especially in deep gray matter. This study also provides evidence supporting the notion that microstructural changes predate morphological changes. Hum Brain Mapp 38:2495-2508, 2017. © 2017 Wiley Periodicals, Inc.

Nencki Affective Picture System: Cross-Cultural Study in Europe and Iran

Although emotions have been assumed conventionally to be universal, recent studies have suggested that various aspects of emotions may be mediated by cultural background. The purpose of our research was to test these contradictory views, in the case of the subjective evaluation of visual affective stimuli. We also sought to validate the recently introduced Nencki Affective Picture System (NAPS) database on a different cultural group. Since there has been, to date, no attempt to compare the emotions of a culturally distinct sample of Iranians with those of Europeans, subjective ratings were collected from 40 Iranians and 39 Europeans. Each cultural group was asked separately to provide normative affective ratings and classify pictures according to discrete emotions. The results were analyzed to identify cultural differences in the ratings of individual images. One hundred and seventy NAPS pictures were rated with regard to the intensity of the basic emotions (happiness, sadness, fear, surprise, anger, and disgust) they elicited, as well as in terms of affective dimensions (valence and arousal). Contrary to previous studies using the International Affective Picture System, our results for Europeans and Iranians show that neither the ratings for affective dimensions nor for basic emotions differed across cultural groups. In both cultural groups, the relationship between valence and arousal ratings could be best described by a classical boomerang-shaped function. However, the content of the pictures (animals, faces, landscapes, objects, or people) had a significant effect on the ratings for valence and arousal. These findings indicate that further studies in cross-cultural affective research should control for the content of stimuli.

Functional alterations of fronto-limbic circuit and default mode network systems in first-episode, drug-naïve patients with major depressive disorder: A meta-analysis of resting-state fMRI data

BACKGROUND

The neurobiological mechanisms of depression are increasingly being explored through resting-state brain imaging studies. However, resting-state fMRI findings have varied, perhaps because of differences between study populations, which included the disorder course and medication use. The aim of our study was to integrate studies of resting-state fMRI and explore the alterations of abnormal brain activity in first-episode, drug-naïve patients with major depressive disorder.

METHODS

Relevant imaging reports in English were searched, retrieved, selected and subjected to analysis by activation likelihood estimation, a coordinate-based meta-analysis technique (final sample, 31 studies). Coordinates extracted from the original reports were assigned to two categories based on effect directionality.

RESULTS

Compared with healthy controls, the first-episode, medication-naïve major depressive disorder patients showed decreased brain activity in the dorsolateral prefrontal cortex, superior temporal gyrus, posterior precuneus, and posterior cingulate, as well as in visual areas within the occipital lobe, lingual gyrus, and fusiform gyrus, and increased activity in the putamen and anterior precuneus.

LIMITATIONS

Not every study that has reported relevant data met the inclusion criteria.

CONCLUSION

Resting-state functional alterations were located mainly in the fronto-limbic system, including the dorsolateral prefrontal cortex and putamen, and in the default mode network, namely the precuneus and superior/middle temporal gyrus. Abnormal functional alterations of the fronto-limbic circuit and default mode network may be characteristic of first-episode, drug-naïve major depressive disorder patients.

Romantic Love Is Associated with Enhanced Inhibitory Control in an Emotional Stop-Signal Task

Purpose: This study explored whether romantic lovers differ in emotion-related inhibitory control capacity from those who are single.

Methods: 88 healthy undergraduate college students participated in the study. Half were currently in love and in a romantic relationship (love group, LG), and half were single and had never been in a romantic relationship (single group, SG). Based on duration of romantic relationship (i.e., love duration), the LG were further divided into two subgroups: “early stage love” and “longer periods of love”. All participants completed an emotional Stop Signal Task, consisting of a variety of human face stimuli displaying either sad or neutral affect.

Results: Results found that relative to SG, lovers showed greater inhibitory control [shorter stop-signal reaction time (SSRT)] during negative emotion condition trials. Furthermore, in early stages of love, SSRT for negative emotion condition trials was significantly shorter compared to that in “longer periods of love” or SG individuals, with no significant differences between the two latter groups.

Conclusion: Compared with individuals who were single, early stage lovers showed greater capacity for inhibiting action during presentation of negative emotional stimuli. Within a greater social context, greater inhibitory control capacity during early stages of love may be related to the successful formation of romantic relationships, particularly to the ability to persevere in goal-directed action despite negative emotional contexts such as that of sadness.

Amygdala subnuclei response and connectivity during emotional processing

The involvement of the human amygdala in emotion-related processing has been studied using functional magnetic resonance imaging (fMRI) for many years. However, despite the amygdala being comprised of several subnuclei, most studies investigated the role of the entire amygdala in processing of emotions. Here we combined a novel anatomical tracing protocol with event-related high-resolution fMRI acquisition to study the responsiveness of the amygdala subnuclei to negative emotional stimuli and to examine intra-amygdala functional connectivity. The greatest sensitivity to the negative emotional stimuli was observed in the centromedial amygdala, where the hemodynamic response amplitude elicited by the negative emotional stimuli was greater and peaked later than for neutral stimuli. Connectivity patterns converge with extant findings in animals, such that the centromedial amygdala was more connected with the nuclei of the basal amygdala than with the lateral amygdala. Current findings provide evidence of functional specialization within the human amygdala.

Neural indicators of emotion regulation via acceptance vs reappraisal in remitted major depressive disorder

Mood disorders are characterized by impaired emotion regulation abilities, reflected in alterations in frontolimbic brain functioning during regulation. However, little is known about differences in brain function when comparing regulatory strategies. Reappraisal and emotional acceptance are effective in downregulating negative affect, and are components of effective depression psychotherapies. Investigating neural mechanisms of reappraisal vs emotional acceptance in remitted major depressive disorder (rMDD) may yield novel mechanistic insights into depression risk and prevention. Thirty-seven individuals (18 rMDD, 19 controls) were assessed during a functional magnetic resonance imaging task requiring reappraisal, emotional acceptance or no explicit regulation while viewing sad images. Lower negative affect was reported following reappraisal than acceptance, and was lower following acceptance than no explicit regulation. In controls, the acceptance > reappraisal contrast revealed greater activation in left insular cortex and right prefrontal gyrus, and less activation in several other prefrontal regions. Compared with controls, the rMDD group had greater paracingulate and right midfrontal gyrus (BA 8) activation during reappraisal relative to acceptance. Compared with reappraisal, acceptance is associated with activation in regions linked to somatic and emotion awareness, although this activation is associated with less reduction in negative affect. Additionally, a history of MDD moderated these effects.

Current Emotion Research in Cognitive Neuroscience: Linking Enhancing and Impairing Effects of Emotion on Cognition

Emotions can have both enhancing and impairing effects on various cognitive processes, from lower (e.g., perceptual) to higher level (e.g., mnemonic and executive) processes. The present article discusses emerging brain imaging evidence linking these opposing effects of emotion, which points to overlapping and dissociable neural systems involving both bottom-up and top-down mechanisms. The link between the enhancing and impairing effects is also discussed in a clinical context, with a focus on posttraumatic stress disorder (PTSD), where these opposing effects tend to co-occur, are exacerbated, and are detrimental. Overall, the present review highlights the need to consider together enhancing and impairing effects of emotion on cognition in studies investigating emotion–cognition interactions.

Effects of acute alcohol consumption and processing of emotion in faces: Implications for understanding alcohol-related aggression

The negative consequences of chronic alcohol abuse are well known, but heavy episodic consumption ("binge drinking") is also associated with significant personal and societal harms. Aggressive tendencies are increased after alcohol but the mechanisms underlying these changes are not fully understood. While effects on behavioural control are likely to be important, other effects may be involved given the widespread action of alcohol. Altered processing of social signals is associated with changes in social behaviours, including aggression, but until recently there has been little research investigating the effects of acute alcohol consumption on these outcomes. Recent work investigating the effects of acute alcohol on emotional face processing has suggested reduced sensitivity to submissive signals (sad faces) and increased perceptual bias towards provocative signals (angry faces) after alcohol consumption, which may play a role in alcohol-related aggression. Here we discuss a putative mechanism that may explain how alcohol consumption influences emotional processing and subsequent aggressive responding, via disruption of orbitofrontal cortex (OFC)-amygdala connectivity. While the importance of emotional processing on social behaviours is well established, research into acute alcohol consumption and emotional processing is still in its infancy. Further research is needed and we outline a research agenda to address gaps in the literature.

Neural correlates of cognitive and affective processing in maltreated youth with posttraumatic stress symptoms: does gender matter?

We investigated the relationship of gender to cognitive and affective processing in maltreated youth with posttraumatic stress disorder symptoms using functional magnetic resonance imaging. Maltreated (N = 29, 13 females, 16 males) and nonmaltreated participants (N = 45, 26 females, 19 males) performed an emotional oddball task that involved detection of targets with fear or scrambled face distractors. Results were moderated by gender. During the executive component of this task, left precuneus/posterior middle cingulate hypoactivation to fear versus calm or scrambled face targets were seen in maltreated versus control males and may represent dysfunction and less resilience in attentional networks. Maltreated males also showed decreased activation in the inferior frontal gyrus compared to control males. No differences were found in females. Posterior cingulate activations positively correlated with posttraumatic stress disorder symptoms. While viewing fear faces, maltreated females exhibited decreased activity in the dorsomedial prefrontal cortex and cerebellum I-VI, whereas maltreated males exhibited increased activity in the left hippocampus, fusiform cortex, right cerebellar crus I, and visual cortex compared to their same-gender controls. Gender by maltreatment effects were not attributable to demographic, clinical, or maltreatment parameters. Maltreated girls and boys exhibited distinct patterns of neural activations during executive and affective processing, a new finding in the maltreatment literature.

Attention modulates the dorsal striatum response to love stimuli

In previous functional magnetic resonance imaging (fMRI) studies concerning romantic love, several brain regions including the caudate and putamen have consistently been found to be more responsive to beloved-related than control stimuli. In those studies, infatuated individuals were typically instructed to passively view the stimuli or to think of the viewed person. In the current study, we examined how the instruction to attend to, or ignore the beloved modulates the response of these brain areas. Infatuated individuals performed an oddball task in which pictures of their beloved and friend served as targets and distractors. The dorsal striatum showed greater activation for the beloved than friend, but only when they were targets. The dorsal striatum actually tended to show less activation for the beloved than the friend when they were distractors. The longer the love and relationship duration, the smaller the response of the dorsal striatum to beloved-distractor stimuli was. We interpret our findings in terms of reinforcement learning. By virtue of using a cognitive task with a full factorial design, we show that the dorsal striatum is not activated by beloved-related information per se, but only by beloved-related information that is attended.

Neural mechanisms of cognitive reappraisal in remitted major depressive disorder

BACKGROUND

Down-regulation of negative emotions by cognitive strategies relies on prefrontal cortical modulation of limbic brain regions, and impaired frontolimbic functioning during cognitive reappraisal has been observed in affective disorders. However, no study to date has examined cognitive reappraisal in unmedicated euthymic individuals with a history of major depressive disorder relative to symptom-matched controls. Given that a history of depression is a critical risk factor for future depressive episodes, investigating the neural mechanisms of emotion regulation in remitted major depressive disorder (rMDD) may yield novel insights into depression risk.

METHOD

We assessed 37 individuals (18 rMDD, 19 controls) with functional magnetic resonance imaging (fMRI) during a task requiring cognitive reappraisal of sad images.

RESULTS

Both groups demonstrated decreased self-reported negative affect after cognitive reappraisal and no group differences in the effects of cognitive reappraisal on mood were evident. Functional MRI results indicated greater paracingulate gyrus (rostral anterior cingulate cortex, Brodmann area 32) activation and decreased right midfrontal gyrus (Brodmann area 6) activation during the reappraisal of sad images.

LIMITATIONS

Trial-by-trial ratings of pre-regulation affect were not collected, limiting the interpretation of post-regulation negative affect scores.

CONCLUSIONS

Results suggest that activation of rostral anterior cingulate cortex, a region linked to the prediction of antidepressant treatment response, and of the right midfrontal gyrus, a region involved in cognitive control in the context of cognitive reappraisal, may represent endophenotypic markers of future depression risk. Future prospective studies will be needed to validate the predictive utility of these neural markers.

Neural signatures of the response to emotional distraction: a review of evidence from brain imaging investigations

Prompt responses to emotional, potentially threatening, stimuli are supported by neural mechanisms that allow for privileged access of emotional information to processing resources. The existence of these mechanisms can also make emotional stimuli potent distracters, particularly when task-irrelevant. The ability to deploy cognitive control in order to cope with emotional distraction is essential for adaptive behavior, while reduced control may lead to enhanced emotional distractibility, which is often a hallmark of affective disorders. Evidence suggests that increased susceptibility to emotional distraction is linked to changes in the processing of emotional information that affect both the basic response to and coping with emotional distraction, but the neural correlates of these phenomena are not clear. The present review discusses emerging evidence from brain imaging studies addressing these issues, and highlights the following three aspects. First, the response to emotional distraction is associated with opposing patterns of activity in a ventral "hot" affective system (HotEmo, showing increased activity) and a dorsal "cold" executive system (ColdEx, showing decreased activity). Second, coping with emotional distraction involves top-down control in order to counteract the bottom-up influence of emotional distraction, and involves interactions between the amygdala and the prefrontal cortex. Third, both the response to and coping with emotional distraction are influenced by individual differences affecting emotional sensitivity and distractibility, which are linked to alterations of both HotEmo and ColdEx neural systems. Collectively, the available evidence identifies specific neural signatures of the response to emotional challenge, which are fundamental to understanding the mechanisms of emotion-cognition interactions in healthy functioning, and the changes linked to individual variation in emotional distractibility and susceptibility to affective disorders.

Common and specific brain responses to scenic emotional stimuli

Processing of emotions has been an enduring topic of interest in neuroimaging research, but studies have mostly used facial emotional stimuli. The aim of this study was to determine neural networks involved in emotion processing using scenic emotional visual stimuli. One hundred and twenty photographs from the International Affective Picture System (IAPS), including ecological scenes of disgust, fear, happiness, and sadness, were presented to 40 healthy participants while they underwent functional magnetic imaging resonance (fMRI). Afterwards they evaluated the emotional content of the pictures in an offline task. The occipito-temporal cortex and the amygdala-hippocampal complex showed a non-specific emotion-related activation, which was more marked in response to negative emotions than to happiness. The temporo-parietal cortex and the ventral anterior cingulate gyrus showed deactivation, with the former being marked for all emotions except fear and the latter being most marked for disgust. The fusiform gyrus showed activation in response to disgust and deactivation in response to happiness or sadness. Brain regions involved in processing of scenic emotion therefore resemble those reported for facial expressions of emotion in that they respond to a range of different emotions, although there appears to be specificity in the intensity and direction of the response.

Electrophysiological correlates of fearful and sad distraction on target processing in adolescents with attention deficit-hyperactivity symptoms and affective disorders

In this study we used event-related brain potentials (ERP) as neural markers of cognitive operations to examine emotion and attentional processing in a population of high-risk adolescents with mental health problems that included attention deficit and hyperactivity disorder (ADHD), anxiety, and depression. We included a healthy control group for comparison purposes, and employed a modified version of the emotional oddball paradigm, consisting of frequent distracters (scrambled pictures), infrequent distracters (sad, fearful, and neutral pictures), and infrequent targets (circles). Participants were instructed to make a right hand button press to targets and a left hand button press to all other stimuli. EEG/ERP recordings were taken using a high-density 256-channel recording system. Behavioral data showed that for both clinical and non-clinical adolescents, reaction time (RT) was slowest in response to the fearful images. Electrophysiological data differentiated emotion and target processing between clinical and non-clinical adolescents. In the clinical group we observed a larger P100 and late positive potential (LPP) in response to fearful compared to sad or neutral pictures. There were no differences in these ERPs in the healthy sample. Emotional modulation of target processing was also identified in the clinical sample, where we observed an increase in P300 amplitude, and a larger sustained LPP in response to targets that followed emotional pictures (fear and sad) compared to targets that followed neutral pictures or other targets. There were no differences in these target ERPs for the healthy participants. Taken together, we suggest that these data provide important and novel evidence of affective and attention dysfunction in this clinical population of adolescents, and offer an example of the disruptive effects of emotional reactivity on basic cognition.

Differential brain response to alcohol cue distractors across stages of alcohol dependence

Altered attention to alcohol-related cues is implicated in the craving and relapse cycle characteristic of alcohol dependence (ALC). Prior cue reactivity studies typically invoke explicit attention to alcohol cues, so the neural response underlying incidental cue exposure remains unclear. Here, we embed infrequent, task-irrelevant alcohol and non-alcohol cues in an attention-demanding task, enabling evaluation of brain responses to distracting alcohol cues. Alcohol dependent individuals, across illness phase (n=44), and controls (n=20) performed a cue-reactivity fMRI target detection task. Significant Group-by-Distractor effects were observed in dorsal anterior cingulate cortex (ACC), inferior parietal lobule, and amygdala. Controls and long-term abstainers increased recruitment of attention and cognitive control regions, while recent and long-term abstainers decreased limbic recruitment to alcohol distractors. Across phases of ALC, self-reported craving positively correlated with cue-related activations in ventral ACC, medial prefrontal cortex, and cerebellum. Results indicate that brain responses elicited by incidental alcohol cues differentiate phases of ALC.

Neural mechanisms of subclinical depressive symptoms in women: a pilot functional brain imaging study

BACKGROUND

Studies of individuals who do not meet criteria for major depressive disorder (MDD) but with subclinical levels of depressive symptoms may aid in the identification of neurofunctional abnormalities that possibly precede and predict the development of MDD. The purpose of this study was to evaluate relations between subclinical levels of depressive symptoms and neural activation patterns during tasks previously shown to differentiate individuals with and without MDD.

METHODS

Functional magnetic resonance imaging (fMRI) was used to assess neural activations during active emotion regulation, a resting state scan, and reward processing. Participants were twelve females with a range of depressive symptoms who did not meet criteria for MDD.

RESULTS

Increased depressive symptom severity predicted (1) decreased left midfrontal gyrus activation during reappraisal of sad stimuli; (2) increased right midfrontal gyrus activation during distraction from sad stimuli; (3) increased functional connectivity between a precuneus seed region and left orbitofrontal cortex during a resting state scan; and (4) increased paracingulate activation during non-win outcomes during a reward-processing task.

CONCLUSIONS

These pilot data shed light on relations between subclinical levels of depressive symptoms in the absence of a formal MDD diagnosis and neural activation patterns. Future studies will be needed to test the utility of these activation patterns for predicting MDD onset in at-risk samples.

Functional imaging of emotion reactivity in opiate-dependent borderline personality disorder

Opiate dependence (OD) and borderline personality disorder (BPD), separately and together, are significant public health problems with poor treatment outcomes. BPD is associated with difficulties in emotion regulation, and brain-imaging studies in BPD individuals indicate differential activation in prefrontal cingulate cortices and their interactions with limbic regions. Likewise, a similar network is implicated in drug cue responsivity in substance abusers. The present, preliminary study used functional MRI to examine activation of this network in comorbid OD/BPD participants when engaged in an "oddball" task that required attention to a target in the context of emotionally negative distractors. Twelve male OD/BPD participants and 12 male healthy controls participated. All OD/BPD participants were taking the opiate replacement medication Suboxone, and a subset of participants was positive for substances of abuse on scan day. Relative to controls, OD/BPD participants demonstrated reduced activation to negative stimuli in the amygdala and anterior cingulate. Unlike previous studies that demonstrated hyperresponsivity in neural regions associated with affective processing in individuals with BPD versus healthy controls, comorbid OD/BPD participants were hyporesponsive to emotional cues. Future studies that also include BPD-only and OD-only groups are necessary to help clarify the individual and potentially synergistic effects of these two conditions.

Emotion recognition in individuals at clinical high-risk for schizophrenia

Problems in the perception of emotional material, in particular deficits in the recognition of negative stimuli, have been demonstrated in schizophrenia including in first-episode samples. However, it is largely unknown if emotion recognition impairment is present in people with subthreshold psychotic symptoms. Here, we examined the capacity to recognize facially expressed emotion and affective prosody in 79 individuals at ultra high-risk for psychosis, 30 clinically stable individuals with first-episode schizophrenia assessed as outpatients during the early recovery phase of illness, and 30 unaffected healthy control subjects. We compared (1) scores for a combined fear-sadness aggregate index across face and voice modalities, (2) summary scores of specific emotions across modalities, and (3) scores for specific emotions for each sensory modality. Findings supported deficits in recognition of fear and sadness across both modalities for the clinical groups (the ultra high-risk and first-episode group) as compared with the healthy controls. Furthermore, planned contrasts indicated that compared with the healthy control subjects, both clinical groups had a significant deficit for fear and sadness recognition in faces and for anger recognition in voices. Specific impairments in emotion recognition may be apparent in people at clinical high-risk for schizophrenia before the full expression of psychotic illness. The results suggest a trait deficit and an involvement of the amygdala in the pathology of ultra high-risk states.

Neural correlates associated with cognitive decline in late-life depression

OBJECTIVES

Persistent cognitive impairment (PCI) after remission of depressive symptoms is a major adverse outcome of late-life depression (LLD). The purpose of this study was to examine neural substrates associated with PCI in LLD.

DESIGN

Longitudinal study.

SETTING

Outpatient depression treatment study at Duke University.

PARTICIPANTS

Twenty-three patients with LLD completed a 2-year follow-up study, and were in a remitted or partially remitted state at Year 2.

METHODS

At first entry to the study (Year 0), all participants had a functional magnetic resonance imaging scan while performing an emotional oddball task. For the purpose of this report, the primary functional magnetic resonance imaging outcome was brain activation during target detection, which is a measure of executive function. The Consortium to Establish a Registry for Alzheimer's Disease neuropsychological battery was used to assess cognitive status yearly, and the Montgomery-Åsberg Depression Rating Scale was used to assess severity of depression at Year 0 and every 6 months thereafter for 2 years. We investigated changes in brain activation at Year 0 associated with PCI over 2 years.

RESULTS

Patients with PCI at the 2-year follow-up date had significantly decreased activation at Year 0 in the dorsal anterior cingulate cortex, hippocampus, inferior frontal cortex, and insula compared to non-PCI patients.

CONCLUSIONS

Our results suggest individuals who have LLD with PCI have decreased activation in the similar neural networks associated with the development of Alzheimer disease among nondepressed individuals. Measuring neural activity in these regions in individuals with LLD may help identify patients at-risk for cognitive impairment.

Neural substrates for processing task-irrelevant emotional distracters in maltreated adolescents with depressive disorders: a pilot study

In this pilot study, neural systems related to cognitive and emotional processing were examined using event-related functional magnetic resonance imaging in 5 maltreated youth with depressive disorders and 11 nonmaltreated healthy participants. Subjects underwent an emotional oddball task, where they detected infrequent ovals (targets) within a continual stream of phase-scrambled images (standards). Sad and neutral images were intermittently presented as task-irrelevant distracters. The maltreated youth revealed significantly decreased activation in the left middle frontal gyrus and right precentral gyrus to target stimuli and significantly increased activation to sad stimuli in bilateral amygdala, left subgenual cingulate, left inferior frontal gyrus, and right middle temporal cortex compared to nonmaltreated subjects. Additionally, the maltreated youth showed significantly decreased activation to both attentional targets and sad distracters in the left posterior middle frontal gyrus compared to nonmaltreated subjects. In this exploratory study of dorsal control and ventral emotional circuits, we found that maltreated youth with distress disorders demonstrated dysfunction of neural systems related to cognitive control and emotional processing.

Processing of emotional distraction is both automatic and modulated by attention: evidence from an event-related fMRI investigation

Traditionally, emotional stimuli have been thought to be automatically processed via a bottom-up automatic "capture of attention" mechanism. Recently, this view has been challenged by evidence that emotion processing depends on the availability of attentional resources. Although these two views are not mutually exclusive, direct evidence reconciling them is lacking. One limitation of previous investigations supporting the traditional or competing views is that they have not systematically investigated the impact of emotional charge of task-irrelevant distraction in conjunction with manipulations of attentional demands. Using event-related fMRI, we investigated the nature of emotion-cognition interactions in a perceptual discrimination task with emotional distraction by manipulating both the emotional charge of the distracting information and the demands of the main task. Our findings show that emotion processing is both automatic and modulated by attention, but emotion and attention were only found to interact when finer assessments of emotional charge (comparison of most vs. least emotional conditions) were considered along with an effective manipulation of processing load (high vs. low). The study also identified brain regions reflecting the detrimental impact of emotional distraction on performance as well as regions involved in coping with such distraction. Activity in the dorsomedial pFC and ventrolateral pFC was linked to a detrimental impact of emotional distraction, whereas the dorsal ACC and lateral occipital cortex were involved in helping with emotional distraction. These findings demonstrate that task-irrelevant emotion processing is subjective to both the emotional content of distraction and the level of attentional demand.

Gray matter volume abnormalities in individuals with cognitive vulnerability to depression: a voxel-based morphometry study

BACKGROUND

The hopelessness theory of depression posits that individuals with negative cognitive styles are at an increased risk for depression following negative life events. In neuroimaging studies, brain gray matter volume abnormalities correlate with the presence of depressive disorders. However, it is unknown whether changes in gray matter volume also appear in healthy individuals with cognitive vulnerability to depression (CVD).

METHODS

30 subjects diagnosed with CVD, 33 first-episode patients with major depressive disorder (MDD), and 32 healthy controls were examined using voxel-based morphometry following magnetic resonance imaging (MRI).

RESULTS

We found significant volumetric differences between three groups in the left precentral gyrus, right fusiform gyrus and the right thalamus. In these regions, compared to controls, CVD subjects showed reduced gray matter volumes in the left precentral gyrus and right fusiform gyrus. MDD patients demonstrated reduced gray matter volume in the left precentral gyrus and increased gray matter volume in the right thalamus. Additionally, CVD individuals had significantly smaller right fusiform gyrus and right thalamus than MDD patients. The weakest-link scores on CSQ were negatively correlated with gray matter volumes in the left precentral gyrus.

CONCLUSIONS

Reductions in brain gray matter volume exist widely in individuals with CVD. In addition, there exist similar abnormalities in gray matter volume in both CVD subjects and MDD patients. Reductions of gray matter volume in the left precentral gyrus might be correlated to the negative cognitive styles, as well as an increased risk for depression.

Impact of BDNF Val66Met and 5-HTTLPR polymorphism variants on neural substrates related to sadness and executive function

The brain-derived neurotrophic factor (BDNF) Val(66) Met allelic variation is linked to both the occurrence of mood disorders and antidepressant response. These findings are not universally observed, and the mechanism by which this variation results in increased risk for mood disorders is unclear. One possible explanation is an epistatic relationship with other neurotransmitter genes associated with depression risk, such as the serotonin-transporter-linked promotor region (5-HTTLPR). Further, it is unclear how the coexistence of the BDNF Met and 5-HTTLPR S variants affects the function of the affective and cognitive control systems. To address this question, we conducted a functional magnetic resonance imaging (fMRI) study in 38 older adults (20 healthy and 18 remitted from major depressive disorder). Subjects performed an emotional oddball task during the fMRI scan and provided blood samples for genotyping. Our analyses examined the relationship between genotypes and brain activation to sad distractors and attentional targets. We found that 5-HTTLPR S allele carriers exhibited stronger activation in the amygdala in response to sad distractors, whereas BDNF Met carriers exhibited increased activation to sad stimuli but decreased activation to attentional targets in the dorsolateral prefrontal and dorsomedial prefrontal cortices. In addition, subjects with both the S allele and Met allele genes exhibited increased activation to sad stimuli in the subgenual cingulate and posterior cingulate. Our results indicate that the Met allele alone or in combination with 5-HTTLPR S allele may increase reactivity to sad stimuli, which might represent a neural mechanism underlying increased depression vulnerability.

The influence of emotional distraction on verbal working memory: an fMRI investigation comparing individuals with schizophrenia and healthy adults

The ability to maintain information over short periods of time (i.e., working memory) is critically important in a variety of cognitive functions including language, planning, and decision-making. Recent functional Magnetic Resonance Imaging (fMRI) research with healthy adults has shown that brain activations evoked during the delay interval of working memory tasks can be reduced by the presentation of distracting emotional events, suggesting that emotional events may take working-memory processes momentarily offline. Both executive function and emotional processing are disrupted in schizophrenia, and here we sought to elucidate the effect of emotional distraction upon brain activity in schizophrenic and healthy adults performing a verbal working memory task. During the delay period between the memoranda and memory probe items, emotional and neutral distractors differentially influenced brain activity in these groups. In healthy adults, the hemodynamic response from posterior cingulate, orbital frontal cortex, and the parietal lobe strongly differentiated emotional from neutral distractors. In striking contrast, schizophrenic adults showed no significant differences in brain activation when processing emotional and neutral distractors. Moreover, the influence of emotional distractors extended into the memory probe period in healthy, but not schizophrenic, adults. The results suggest that although emotional items are highly salient for healthy adults, emotional items are no more distracting than neutral ones to individuals with schizophrenia.

Serotonin transporter gene polymorphisms and brain function during emotional distraction from cognitive processing in posttraumatic stress disorder

BACKGROUND

Serotonergic system dysfunction has been implicated in posttraumatic stress disorder (PTSD). Genetic polymorphisms associated with serotonin signaling may predict differences in brain circuitry involved in emotion processing and deficits associated with PTSD. In healthy individuals, common functional polymorphisms in the serotonin transporter gene (SLC6A4) have been shown to modulate amygdala and prefrontal cortex (PFC) activity in response to salient emotional stimuli. Similar patterns of differential neural responses to emotional stimuli have been demonstrated in PTSD but genetic factors influencing these activations have yet to be examined.

METHODS

We investigated whether SLC6A4 promoter polymorphisms (5-HTTLPR, rs25531) and several downstream single nucleotide polymorphisms (SNPs) modulated activity of brain regions involved in the cognitive control of emotion in post-9/11 veterans with PTSD. We used functional MRI to examine neural activity in a PTSD group (n = 22) and a trauma-exposed control group (n = 20) in response to trauma-related images presented as task-irrelevant distractors during the active maintenance period of a delayed-response working memory task. Regions of interest were derived by contrasting activation for the most distracting and least distracting conditions across participants.

RESULTS

In patients with PTSD, when compared to trauma-exposed controls, rs16965628 (associated with serotonin transporter gene expression) modulated task-related ventrolateral PFC activation and 5-HTTLPR tended to modulate left amygdala activation. Subsequent to combat-related trauma, these SLC6A4 polymorphisms may bias serotonin signaling and the neural circuitry mediating cognitive control of emotion in patients with PTSD.

CONCLUSIONS

The SLC6A4 SNP rs16965628 and 5-HTTLPR are associated with a bias in neural responses to traumatic reminders and cognitive control of emotions in patients with PTSD. Functional MRI may help identify intermediate phenotypes and dimensions of PTSD that clarify the functional link between genes and disease phenotype, and also highlight features of PTSD that show more proximal influence of susceptibility genes compared to current clinical categorizations.

Affective cognition and its disruption in mood disorders

In this review, we consider affective cognition, responses to emotional stimuli occurring in the context of cognitive evaluation. In particular, we discuss emotion categorization, biasing of memory and attention, as well as social/moral emotion. We discuss limited neuropsychological evidence suggesting that affective cognition depends critically on the amygdala, ventromedial frontal cortex, and the connections between them. We then consider neuroimaging studies of affective cognition in healthy volunteers, which have led to the development of more sophisticated neural models of these processes. Disturbances of affective cognition are a core and specific feature of mood disorders, and we discuss the evidence supporting this claim, both from behavioral and neuroimaging perspectives. Serotonin is considered to be a key neurotransmitter involved in depression, and there is a considerable body of research exploring whether serotonin may mediate disturbances of affective cognition. The final section presents an overview of this literature and considers implications for understanding the pathophysiology of mood disorder as well as developing and evaluating new treatment strategies.

Neuroimaging support for discrete neural correlates of basic emotions: a voxel-based meta-analysis

What is the basic structure of emotional experience and how is it represented in the human brain? One highly influential theory, discrete basic emotions, proposes a limited set of basic emotions such as happiness and fear, which are characterized by unique physiological and neural profiles. Although many studies using diverse methods have linked particular brain structures with specific basic emotions, evidence from individual neuroimaging studies and from neuroimaging meta-analyses has been inconclusive regarding whether basic emotions are associated with both consistent and discriminable regional brain activations. We revisited this question, using activation likelihood estimation (ALE), which allows spatially sensitive, voxelwise statistical comparison of results from multiple studies. In addition, we examined substantially more studies than previous meta-analyses. The ALE meta-analysis yielded results consistent with basic emotion theory. Each of the emotions examined (fear, anger, disgust, sadness, and happiness) was characterized by consistent neural correlates across studies, as defined by reliable correlations with regional brain activations. In addition, the activation patterns associated with each emotion were discrete (discriminable from the other emotions in pairwise contrasts) and overlapped substantially with structure-function correspondences identified using other approaches, providing converging evidence that discrete basic emotions have consistent and discriminable neural correlates. Complementing prior studies that have demonstrated neural correlates for the affective dimensions of arousal and valence, the current meta-analysis results indicate that the key elements of basic emotion views are reflected in neural correlates identified by neuroimaging studies.

The effects of Brief Behavioral Activation Therapy for Depression on cognitive control in affective contexts: An fMRI investigation

BACKGROUND

Unipolar major depressive disorder (MDD) is characterized by impaired cognitive control in affective contexts, but the potential for psychotherapy to affect the neural correlates of these functions has not been evaluated.

METHOD

Twelve adults with and 15 adults without MDD participated in two identical functional magnetic resonance imaging (fMRI) scans that utilized a task requiring cognitive control in both sad and neutral contexts. Between scans, MDD outpatients received Behavioral Activation Therapy for Depression, a psychotherapy modality designed to increase engagement with positive stimuli and reduce avoidance behaviors.

RESULTS

Seventy-five percent of adults with MDD were treatment responders, achieving post-treatment Hamilton Rating Scale for Depression score of six or below. Consistent with predictions, psychotherapy resulted in decreased activation in response to cognitive control stimuli presented within a sad context in prefrontal structures, including the paracingulate gyrus, the right orbital frontal cortex, and the right frontal pole. Furthermore, the magnitude of pretreatment activation in the paracingulate gyrus cluster responsive to psychotherapy predicted the magnitude of depressive symptom change after psychotherapy.

LIMITATIONS

Replication with larger samples is needed, as are follow-up studies that involve placebo control groups, wait-list control groups, and alternative forms of antidepressant intervention.

CONCLUSIONS

Behavioral Activation Therapy for Depression improves depressive symptoms and concomitantly influences brain systems mediating cognitive control in affective contexts.

Increased amygdala activation during automatic processing of facial emotion in schizophrenia

Schizophrenia patients show abnormalities in the processing of facial emotion. The amygdala is a central part of a brain network that is involved in the perception of facial emotions. Previous functional neuroimaging studies on the perception of facial emotion in schizophrenia have focused almost exclusively on controlled processing. In the present study, we investigated the automatic responsivity of the amygdala to emotional faces in schizophrenia and its relationship to clinical symptomatology by applying an affective priming task. 3-T fMRI was utilized to examine amygdala responses to sad and happy faces masked by neutral faces in 12 schizophrenia patients and 12 healthy controls. The Positive and Negative Syndrome Scale (PANSS) was administered to assess current symptomatology. Schizophrenia patients exhibited greater automatic amygdala responses to sad and happy faces relative to controls. Amygdala responses to masked sad and happy expressions were positively correlated with the negative subscale of the PANSS. Schizophrenia patients appear to be characterized by amygdalar hyperresponsiveness to negative and positive facial expressions on an automatic processing level. Heightened automatic amygdala responsivity could be involved in the development and maintenance of negative symptoms in schizophrenia.

The BOLD signal in the amygdala does not differentiate between dynamic facial expressions

The amygdala has been considered to be essential for recognizing fear in other people's facial expressions. Recent studies shed doubt on this interpretation. Here we used movies of facial expressions instead of static photographs to investigate the putative fear selectivity of the amygdala using fMRI under more ecological conditions. The amygdala was found to respond more to movies of facial expressions than to pattern motion, but no differences were found between the responses to neutral, happy, disgusted and fearful facial expressions. This lack of emotional selectivity was replicated in three experiments using three different tasks (passive observation, delayed match to sample and viewing for imitation) and two different analysis methods (voxel-by-voxel and anatomical region of interest). Our data therefore provide strong support for the idea that under more ecologically valid conditions, the contribution of the amygdala towards the detection of fearful facial expressions must be more indirect than previously assumed.