Attenuating age-related learning deficits: emotional valenced feedback interacts with task complexity

Previous research reveals that older adults sometimes show enhanced processing of emotionally positive stimuli relative to negative stimuli, but that this positivity bias reverses to become a negativity bias when cognitive control resources are less available. In this study, we test the hypothesis that emotionally positive feedback will attenuate well-established age-related deficits in rule learning whereas emotionally negative feedback will amplify age deficits-but that this pattern will reverse when the task involves a high cognitive load. Experiment 1 used emotional face feedback and revealed an interaction among age, valence of the feedback, and task load. When the task placed minimal load on cognitive control resources, happy-face feedback attenuated age-related deficits in initial rule learning and angry-face feedback led to age-related deficits in initial rule learning and set shifting. However, when the task placed a high load on cognitive control resources, we found that angry-face feedback attenuated age-related deficits in initial rule learning and set shifting whereas happy-face feedback led to age-related deficits in initial rule learning and set shifting. Experiment 2 used less emotional point feedback and revealed age-related deficits in initial rule learning and set shifting under low and high cognitive load for point-gain and point-loss conditions. The research presented here demonstrates that emotional feedback can attenuate age-related learning deficits-but only positive feedback for tasks with a low cognitive load and negative feedback for tasks with high cognitive load.

Stop feeling: inhibition of emotional interference following stop-signal trials

Although a great deal of literature has been dedicated to the mutual links between emotion and the selective attention component of executive control, there is very little data regarding the links between emotion and the inhibitory component of executive control. In the current study we employed an emotional stop-signal task in order to examine whether emotion modulates and is modulated by inhibitory control. Results replicated previous findings showing reduced inhibitory control [longer stop-signal reaction time (SSRT)] following negative, compared to neutral pictures. Most importantly, results show decreased emotional interference following stop-signal trials. These results show that the inhibitory control component of executive control can serve to decrease emotional effects. We suggest that inhibitory control and emotion have a two-way connection in which emotion disrupts inhibitory control and activation of inhibitory control disrupts emotion.

Functional brain activation to emotionally valenced faces in school-aged children with a history of preschool-onset major depression

BACKGROUND

Recent research has demonstrated that clinical depression can emerge as early as the preschool period. Here, we examine brain function in children with a history of preschool-onset depression (PO-MDD) in comparison with healthy children.

METHODS

Participants were medication naïve school-aged children (ages 7-11) with PO-MDD (n = 22) or no psychiatric history (n = 16) followed longitudinally as part of the Preschool Depression Study. We used functional magnetic resonance imaging measures of blood oxygen level-dependent signal to examine functional brain activity in response to emotionally valenced faces (sad, fearful, angry, happy, neutral) following a negative mood induction provided to all children.

RESULTS

In categorical group comparisons, children with PO-MDD demonstrated increased activity in parietal cortex in response to sad faces but no differences in brain activity in a priori regions of interest (e.g., amygdala). However, in dimensional analyses, the severity of depression symptoms at the baseline preschool assessment predicted increased responses to sad faces in amygdala, hippocampal, parietal, and orbital frontal regions.

CONCLUSIONS

School-aged children with a history of PO-MDD showed patterns of functional brain responses to emotionally evocative stimuli similar to patterns found in adults and adolescents with major depression. These patterns were most strongly related to the severity of depression during the preschool period, suggesting that the magnitude of early symptoms may be particularly important for understanding altered brain function. These findings suggest that an early episode of depression before age 6 may be associated with enduring brain change or may represent a biomarker that was present even before the preschool episode.

Short-term SSRI treatment normalises amygdala hyperactivity in depressed patients

BACKGROUND

Antidepressant drugs such as selective serotonin re-uptake inhibitors (SSRIs) remediate negative biases in emotional processing in depressed patients in both behavioural and neural outcome measures. However, it is not clear if these effects occur before, or as a consequence of, changes in clinical state.

METHOD

In the present study, we investigated the effects of short-term SSRI treatment in depressed patients on the neural response to fearful faces prior to clinical improvement in mood. Altogether, 42 unmedicated depressed patients received SSRI treatment (10 mg escitalopram daily) or placebo in a randomised, parallel-group design. The neural response to fearful and happy faces was measured on day 7 of treatment using functional magnetic resonance imaging. A group of healthy controls was imaged in the same way.

RESULTS

Amygdala responses to fearful facial expressions were significantly greater in depressed patients compared to healthy controls. However, this response was normalised in patients receiving 7 days treatment with escitalopram. There was no significant difference in clinical depression ratings at 7 days between the escitalopram and placebo-treated patients.

CONCLUSIONS

Our results suggest that short-term SSRI treatment in depressed patients remediates amygdala hyperactivity in response to negative emotional stimuli prior to clinical improvement in depressed mood. This supports the hypothesis that the clinical effects of antidepressant treatment may be mediated in part through early changes in emotional processing. Further studies will be needed to show if these early effects of antidepressant medication predict eventual clinical outcome.

Using an experimental medicine model to understand the antidepressant potential of the N-Methyl-D-aspartic acid (NMDA) receptor antagonist memantine

There is growing interest in the role of the glutamatergic system both in depression and as a novel target for treatments. Preclinical studies suggested that the non-competitive N-Methyl-D-aspartic acid (NMDA) receptor antagonist memantine might have antidepressant properties, but a randomised controlled trial failed to support this. A healthy volunteer model of emotional processing was used to assess the neuropsychological profile of action of memantine. Healthy volunteers (n=32) were randomised to receive a single dose of memantine (10 mg) or placebo, and subsequently completed a battery of tasks measuring emotional processing, including facial expression recognition, emotional memory, dot-probe and emotion-potentiated startle tasks, as well as working and verbal memory. Memantine treated volunteers showed an increased emotion-potentiated startle, and a reduced bias for negative items in emotional recognition memory. There were no effects of the drug on any other aspect of emotional or non-emotional information processing. These results suggest that a single dose of memantine produces an early anxiogenic response in the emotion-potentiated startle similar to that seen following a single dose of the selective serotonin reuptake inhibitor, citalopram. However, the overall profile of effects is more limited than that which might be expected in response to a conventional antidepressant.

Serotonin transporter genotype differentially modulates neural responses to emotional words following tryptophan depletion in patients recovered from depression and healthy volunteers

Previous studies have suggested that polymorphism in the serotonin transporter gene (5-HTTLPR) influences responses to serotonergic manipulation, with opposite effects in patients recovered from depression (rMDD) and controls. Here we sought to clarify the neurocognitive mechanisms underpinning these surprising results. Twenty controls and 23 rMDD subjects completed the study; functional magnetic resonance imaging (fMRI) and genotype data were available for 17 rMDD subjects and 16 controls. Following tryptophan or sham depletion, subjects performed an emotional-processing task during fMRI. Although no genotype effects on mood were identified, significant genotype*diagnosis*depletion interactions were observed in the hippocampus and subgenual cingulate in response to emotionally valenced words. In both regions, tryptophan depletion increased responses to negative words, relative to positive words, in high-expression controls, previously identified as being at low-risk for mood change following this procedure. By contrast, in higher-risk low-expression controls and high-expression rMDD subjects, tryptophan depletion had the opposite effect. Increased neural responses to negative words following tryptophan depletion may reflect an adaptive mechanism promoting resilience to mood change following perturbation of the serotonin system, which is reversed in sub-groups vulnerable to developing depressive symptoms. However, this interpretation is complicated by our failure to replicate previous findings of increased negative mood following tryptophan depletion.

Alterations in neural processing and psychopathology in children raised in institutions

CONTEXT

Young children raised in institutional settings experience severe deprivation in social, emotional, and cognitive stimulation. Although this deprivation is likely to disrupt brain development in ways that increase the risk for psychopathology, neurodevelopmental mechanisms linking adverse early environments to psychopathology remain poorly understood.

OBJECTIVE

To examine whether abnormalities in the neural processing of facial and emotional stimuli are related to the high rates of psychopathology observed among institutionally reared children.

DESIGN, SETTING, AND PARTICIPANTS

Data were drawn from the Bucharest Early Intervention Project, a cohort of children raised in institutions in Romania and an age-matched sample of community control subjects. At entry to the study (mean age, 22 months), event-related potentials were used to measure neural processing in 2 tasks: familiar and unfamiliar faces (n=114) and facial displays of emotion (n=74).

MAIN OUTCOME MEASURES

Psychiatric symptoms were assessed using the Preschool Age Psychiatric Assessment among children aged 54 months.

RESULTS

As previously reported, institutionally reared children had elevated symptoms of attention-deficit/hyperactivity disorder (ADHD), anxiety, depression, and disruptive behavior compared with control children, and peak amplitudes of the P100 and P700 in response to facial stimuli were blunted among institutionalized children compared with community children in both tasks. Current analyses reveal that children with reduced P100 and P700 amplitudes in response to facial stimuli exhibited higher levels of ADHD and anxiety symptoms. Peak amplitude of the P700 in response to facial stimuli significantly mediated the association between institutional rearing and ADHD symptoms at 54 months.

CONCLUSION

Exposure to institutional rearing disrupts the P700, conferring risk for the onset of psychopathology. The high levels of ADHD symptoms among children exposed to early life deprivation may be attributable, in part, to abnormal patterns of neurodevelopment generated by these adverse rearing environments.

The effects of mindfulness-based cognitive therapy on affective memory recall dynamics in depression: a mechanistic model of rumination

OBJECTIVES

converging research suggests that mindfulness training exerts its therapeutic effects on depression by reducing rumination. Theoretically, rumination is a multifaceted construct that aggregates multiple neurocognitive aspects of depression, including poor executive control, negative and overgeneral memory bias, and persistence or stickiness of negative mind states. Current measures of rumination, most-often self-reports, do not capture these different aspects of ruminative tendencies, and therefore are limited in providing detailed information about the mechanisms of mindfulness.

METHODS

we developed new insight into the potential mechanisms of rumination, based on three model-based metrics of free recall dynamics. These three measures reflect the patterns of memory retrieval of valenced information: the probability of first recall (Pstart) which represents initial affective bias, the probability of staying with the same valence category rather than switching, which indicates strength of positive or negative association networks (Pstay), and probability of stopping (Pstop) or ending recall within a given valence, which indicates persistence or stickiness of a mind state. We investigated the effects of Mindfulness-Based Cognitive Therapy (MBCT; N = 29) vs. wait-list control (N = 23) on these recall dynamics in a randomized controlled trial in individuals with recurrent depression. Participants completed a standard laboratory stressor, the Trier Social Stress Test, to induce negative mood and activate ruminative tendencies. Following that, participants completed a free recall task consisting of three word lists. This assessment was conducted both before and after treatment or wait-list.

RESULTS

while MBCT participant's Pstart remained relatively stable, controls showed multiple indications of depression-related deterioration toward more negative and less positive bias. Following the intervention, MBCT participants decreased in their tendency to sustain trains of negative words and increased their tendency to sustain trains of positive words. Conversely, controls showed the opposite tendency: controls stayed in trains of negative words for longer, and stayed in trains of positive words for less time relative to pre-intervention scores. MBCT participants tended to stop recall less often with negative words, which indicates less persistence or stickiness of negatively valenced mental context.

CONCLUSION

MBCT participants showed a decrease in patterns that may perpetuate rumination on all three types of recall dynamics (Pstart, Pstay, and Pstop), compared to controls. MBCT may weaken the strength of self-perpetuating negative associations networks that are responsible for the persistent and "sticky" negative mind states observed in depression, and increase the positive associations that are lacking in depression. This study also offers a novel, objective method of measuring several indices of ruminative tendencies indicative of the underlying mechanisms of rumination.

Posttraumatic stress disorder and the nature of trauma

The role of psychological trauma (eg, rape, physical assaults, torture, motor vehicle accidents) as an etiological factor in mental disorders, anticipated as early as the 19th century by Janet, Freud, and Breuer, and more specifically during World War I and II by Kardiner, was “rediscovered” some 20 years ago in the wake of the psychological traumas inflicted by the Vietnam war and the discussion “in the open ” of sexual abuse and rape by the women's liberation movement, 1980 marked a major turning point, with the incorporation of the diagnostic construct of posttraumatic stress disorder (PTSD) into the 3rd edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-III) and the definition of its main diagnostic criteria (reexperiencing of the traumatic event, avoidance of stimuli associated with the trauma, and symptoms of increased arousal). Initially described as resulting from a onetime severe traumatic incident, PTSD has now been shown to be triggered by chronic multiple traumas as well. This “state-of-the-art” article discusses past and current understanding of the disorder, with particular emphasis on the recent explosive developments in neuroimaging and other fields of the neurosciences that have highlighted the complex interrelationships between the psychological, psychiatric, biological, and neuroanatomical components of the disorder, and opened up entirely new therapeutic perspectives on how to help the victims of trauma overcome their past.

Anhedonia predicts altered processing of happy faces in abstinent cigarette smokers

RATIONALE

Anhedonia-diminished capacity to experience pleasure-is associated with tobacco dependence and smoking cessation failure. However, the mechanisms linking anhedonia and smoking are unclear.

OBJECTIVES

This study examined whether trait anhedonia predicted cognitive processing of emotional faces during experimentally manipulated acute tobacco deprivation in smokers. Because nicotine may offset reward processing deficits in anhedonia and these deficits may become expressed during abstinence, we hypothesized that anhedonia would predict diminished cognitive processing of happy (versus neutral) facial expressions in nicotine deprived, but not nondeprived states.

METHODS

Smokers not attempting to quit (n = 75, 10+ cig/day) completed anhedonia questionnaires in a baseline session. Participants then attended two counterbalanced experimental sessions: one following 18-h of tobacco abstinence and one after unrestricted smoking. At both sessions, they completed a computer-based measure of attentional interference induced by emotional facial expressions.

RESULTS

The extent to which anhedonia predicted attentional interference induced by happy faces differed as a function of deprivation status (ps ≤ .04, η (p) (2) s > .06). Anhedonia predicted lower interference by happy (versus neutral) faces in the deprived condition (r = -.28, p = .02), but not in the nondeprived condition (r = .08, p = .51). Analyses of a secondary measure of anhedonia found marginally significant effects in the same direction.

CONCLUSIONS

These findings indicate that disrupted processing of positively valenced social cues occurs upon abstinence in high-anhedonia individuals. This alteration may motivate reinstatement of smoking in order to remediate these deficits. More broadly, these results suggest that the neuropharmacological pathways affected by nicotine may underlie disrupted emotional processing in anhedonia-a prominent feature in several psychiatric disorders.

Neural response to emotional stimuli during experimental human endotoxemia

Increases in peripheral cytokines during acute inflammation may affect various neuropsychological functions. The aim of this functional magnetic resonance imaging (fMRI) study was to investigate the effects of acute endotoxemia on mood and the neural response to emotionally aversive visual stimuli in healthy human subjects. In a double-blind, randomized crossover study, 18 healthy males received a bolus injection of bacterial lipopolysaccharide (LPS; 0.4 ng/kg) or saline. Plasma levels of pro- and anti-inflammatory cytokines and cortisol as well as mood ratings were analyzed together with the blood-oxygen-level dependent (BOLD) response during the presentation of aversive versus neutral pictures. Endotoxin administration induced pronounced transient increases in plasma levels of TNF-α, IL-1ra, IL-6, IL-10, and cortisol. Positive mood was decreased and state anxiety increased. In addition, activation of right inferior orbitofrontal cortex (OFC) in response to emotional visual stimuli was significantly increased in the LPS condition. Increased prefrontal activation during the presentation of emotional material may reflect enhanced cognitive regulation of emotions as an adaptive response during an acute inflammation. These findings may have implications for the putative role of inflammatory processes in the pathophysiology of depression.

ADORA2A Gene variation, caffeine, and emotional processing: a multi-level interaction on startle reflex

There is converging evidence for genetic, biochemical, and neuropsychological factors to increase the risk for anxiety and anxiety disorders. The pathogenesis of anxiety disorders is assumed to be influenced by a complex interaction of these individual risk factors on several levels, affecting intermediate phenotypes of anxiety such as the startle reflex. Thus, in the present double-blind, placebo-controlled study we attempted to paradigmatically investigate a multi-level pathogenetic model of anxiety by testing the effect of 300 mg caffeine citrate as an antagonist at the adenosine A2A receptor vs placebo on the emotion-potentiated (unpleasant, neutral, and pleasant International Affective Picture System pictures) startle reflex in 110 healthy individuals (male=56, female=54) stratified for the adenosine A2A receptor (ADORA2A) 1976T>C polymorphism (rs5751876). In addition to the expected main effect of picture category (highest startle amplitude for unpleasant, lowest for pleasant pictures) groups across all ADORA2A 1976T>C genotype and intervention (caffeine vs placebo) groups, an interaction effect of genotype, intervention, and picture category was discerned: In ADORA2A 1976TT risk genotype carriers, highest startle magnitudes were observed after caffeine administration in response to unpleasant pictures, with this effect arising particularly from the female subgroup. Our data point to a complex, multi-level, and potentially gender-specific pathogenetic model of anxiety, with genetic and biochemical factors interactively increasing the risk of maladaptive emotional processing and thereby possibly also anxiety disorders. The present findings may eventually aid in improving primary and secondary prevention by sharpening the risk profiles of anxiety-prone individuals.

Using an experimental medicine model to explore combination effects of pharmacological and cognitive interventions for depression and anxiety

Selective serotonergic reuptake inhibitors (SSRIs) and cognitive therapies are effective in the treatment of anxiety and depression. Previous research suggests that both forms of treatments may work by altering cognitive biases in the processing of affective information. The current study assessed the effects of combining an SSRI with a cognitive intervention on measures of affective processing bias and resilience to external challenge. A total of 62 healthy participants were randomly assigned to receive either 7 days of citalopram (20 mg) or placebo capsules while also completing either an active or a control version of a computerized cognitive bias training task. After treatment, standard measures of affective processing bias were collected. Participants' resilience to external stress was also tested by measuring the increase in negative symptoms induced by a negative mood induction. Participants who received both citalopram and the active cognitive bias training task showed a smaller alteration in emotional memory and categorization bias than did those who received either active intervention singly. The degree to which memory for negative information was altered by citalopram predicted participants' resistance to the negative mood induction. These results suggest that co-administration of an SSRI and a cognitive training intervention can reduce the effectiveness of either treatment alone in terms of anxiety- and depression-relevant emotional processing. More generally, the findings suggest that pinpointing the cognitive actions of treatments may inform future development of combination strategies in mental health.

Tryptophan depletion and emotional processing in healthy volunteers at high risk for depression

BACKGROUND

Studies in depressed patients have demonstrated the presence of emotional bias toward negative stimuli, as well as dysregulated brain serotonin function. The present study compared the effects of acute tryptophan depletion (ATD) on both an emotional processing and a planning task in never-depressed healthy volunteers at high and low familial risk for depression.

METHODS

Young adults with no personal psychiatric history were stratified into two groups based on family history (n = 25). Participants were enrolled in a randomized, double-blind, placebo-controlled crossover ATD study and completed the affective go/no-go and Tower of London tasks once during each condition.

RESULTS

There was a significant treatment by valence by group interaction on the affective go/no-go, driven primarily by a greater frequency of inappropriate responses to sad than to happy distracters in the high-risk group during ATD. No group differences were observed on the Tower of London.

CONCLUSIONS

Asymptomatic individuals at high familial risk for depression showed abnormalities in emotional processing while undergoing experimentally induced tryptophan depletion. These findings support emotional processing disturbances as potential trait-level abnormalities associated with the risk of mood disorder.

A novel theory of experiential avoidance in generalized anxiety disorder: a review and synthesis of research supporting a contrast avoidance model of worry

An important emphasis of the literature on generalized anxiety disorder (GAD) has been to achieve a greater understanding of the function of emotion (e.g., avoidance, dysregulation) in the etiology and maintenance of this disorder. The purpose of the following paper is to propose a new way of conceptualizing emotional sequelae in GAD by detailing the Contrast Avoidance Model of Worry. In presenting this model, we review theory and data that led to our current position, which is that individuals with GAD are more sensitive to feeling emotionally vulnerable to unexpected negative events, and that worry (the key pathological feature of GAD) is employed to prolong and maintain a negative emotional state thereby avoiding an unexpected negative emotional shift, or contrast experience. We also discuss implications for treatment given the presence of a new target for emotional exposure techniques. Finally, we establish the Contrast Avoidance Model within the framework of extant theories and models of pathogenic processes of GAD.

Functional magnetic resonance imaging brain activation in bipolar mania: evidence for disruption of the ventrolateral prefrontal-amygdala emotional pathway

BACKGROUND

Bipolar I disorder is defined by the occurrence of mania. The presence of mania, coupled with a course of illness characterized by waxing and waning of affective symptoms, suggests that bipolar disorder arises from dysfunction of neural systems that maintain emotional arousal and homeostasis. We used functional magnetic resonance imaging (fMRI) to study manic bipolar subjects as they performed a cognitive task designed to examine the ventrolateral prefrontal emotional arousal network.

METHODS

We used fMRI to study regional brain activation in 40 DSM-IV manic bipolar I patients and 36 healthy subjects while they performed a continuous performance task with emotional and neutral distracters. Event-related region-of-interest analyses were performed to test the primary hypothesis. Voxelwise analyses were also completed.

RESULTS

Compared with healthy subjects, the manic subjects exhibited blunted activation to emotional and neutral images, but not targets, across most of the predefined regions of interest. Several additional brain regions identified in the voxelwise analysis also exhibited similar differences between groups, including right parahippocampus, right lingual gyrus, and medial thalamus. In addition to these primary findings, the manic subjects also exhibited increased activation in response to targets in a number of brain regions that were primarily associated with managing affective stimuli. Group differences did not appear to be secondary to medication exposure or other confounds.

CONCLUSIONS

Bipolar manic subjects exhibit blunted brain fMRI response to emotional cues throughout the ventrolateral prefrontal emotional arousal network. Disruption of this emotional network may contribute to the mood dysregulation of bipolar disorder.

Abnormal left and right amygdala-orbitofrontal cortical functional connectivity to emotional faces: state versus trait vulnerability markers of depression in bipolar disorder

BACKGROUND

Amygdala-orbitofrontal cortical (OFC) functional connectivity (FC) to emotional stimuli and relationships with white matter remain little examined in bipolar disorder individuals (BD).

METHODS

Thirty-one BD (type I; n = 17 remitted; n = 14 depressed) and 24 age- and gender-ratio-matched healthy individuals (HC) viewed neutral, mild, and intense happy or sad emotional faces in two experiments. The FC was computed as linear and nonlinear dependence measures between amygdala and OFC time series. Effects of group, laterality, and emotion intensity upon amygdala-OFC FC and amygdala-OFC FC white matter fractional anisotropy (FA) relationships were examined.

RESULTS

The BD versus HC showed significantly greater right amygdala-OFC FC (p < or = .001) in the sad experiment and significantly reduced bilateral amygdala-OFC FC (p = .007) in the happy experiment. Depressed but not remitted female BD versus female HC showed significantly greater left amygdala-OFC FC (p = .001) to all faces in the sad experiment and reduced bilateral amygdala-OFC FC to intense happy faces (p = .01). There was a significant nonlinear relationship (p = .001) between left amygdala-OFC FC to sad faces and FA in HC. In BD, antidepressants were associated with significantly reduced left amygdala-OFC FC to mild sad faces (p = .001).

CONCLUSIONS

In BD, abnormally elevated right amygdala-OFC FC to sad stimuli might represent a trait vulnerability for depression, whereas abnormally elevated left amygdala-OFC FC to sad stimuli and abnormally reduced amygdala-OFC FC to intense happy stimuli might represent a depression state marker. Abnormal FC measures might normalize with antidepressant medications in BD. Nonlinear amygdala-OFC FC-FA relationships in BD and HC require further study.

Elevated amygdala activity to sad facial expressions: a state marker of bipolar but not unipolar depression

BACKGROUND

Difficulties in emotion processing and poor social function are common to bipolar disorder (BD) and major depressive disorder (MDD) depression, resulting in many BD depressed individuals being misdiagnosed with MDD. The amygdala is a key region implicated in processing emotionally salient stimuli, including emotional facial expressions. It is unclear, however, whether abnormal amygdala activity during positive and negative emotion processing represents a persistent marker of BD regardless of illness phase or a state marker of depression common or specific to BD and MDD depression.

METHODS

Sixty adults were recruited: 15 depressed with BD type 1 (BDd), 15 depressed with recurrent MDD, 15 with BD in remission (BDr), diagnosed with DSM-IV and Structured Clinical Interview for DSM-IV Research Version criteria; and 15 healthy control subjects (HC). Groups were age- and gender ratio-matched; patient groups were matched for age of illness onset and illness duration; depressed groups were matched for depression severity. The BDd were taking more psychotropic medication than other patient groups. All individuals participated in three separate 3T neuroimaging event-related experiments, where they viewed mild and intense emotional and neutral faces of fear, happiness, or sadness from a standardized series.

RESULTS

The BDd-relative to HC, BDr, and MDD-showed elevated left amygdala activity to mild and neutral facial expressions in the sad (p < .009) but not other emotion experiments that was not associated with medication. There were no other significant between-group differences in amygdala activity.

CONCLUSIONS

Abnormally elevated left amygdala activity to mild sad and neutral faces might be a depression-specific marker in BD but not MDD, suggesting different pathophysiologic processes for BD versus MDD depression.

The effects of tryptophan depletion on neural responses to emotional words in remitted depression

BACKGROUND

Major depressive disorder (MDD) has been associated with both dysfunction of the central serotonergic system and abnormal responses to emotional stimuli. We used acute tryptophan depletion (ATD) to investigate the effect of temporarily reducing brain serotonin synthesis on neural and behavioral responses to emotional stimuli in remitted MDD subjects (rMDD) and healthy control subjects.

METHODS

Twenty control subjects and 23 rMDD subjects who had been unmedicated and in remission for > or =3 months completed the study. Following tryptophan or sham depletion, participants performed an emotional-processing task during functional magnetic resonance imaging. In addition, resting state regional blood flow was measured using arterial spin labeling.

RESULTS

Neither group exhibited significant mood change following ATD. However, tryptophan depletion differentially affected the groups in terms of hemodynamic responses to emotional words in a number of structures implicated in the pathophysiology of MDD, including medial thalamus and caudate. These interactions were driven by increased responses to emotional words in the control subjects, with little effect in the patients under the ATD condition. Following ATD, habenula blood flow increased significantly in the rMDD subjects relative to the control subjects, and increasing amygdala blood flow was associated with more negative emotional bias score across both groups.

CONCLUSIONS

These data provide evidence for elevated habenula blood flow and alterations in the neural processing of emotional stimuli following ATD in rMDD subjects, even in the absence of overt mood change. However, further studies are required to determine whether these findings represent mechanisms of resilience or vulnerability to MDD.

Emotional processing in PTSD: heightened negative emotionality to unpleasant photographic stimuli

This study evaluated evidence for 2 forms of emotional abnormality in posttraumatic stress disorder (PTSD): numbing and heightened negative emotionality. Forty-nine male veterans with PTSD and 75 without the disorder rated their emotional responses to photographs that depicted scenes of Vietnam combat or were drawn from the International Affective Picture System (Lang et al., 2005). Images varied in their trauma-relatedness and affective qualities. A series of repeated measures ANOVAs revealed that Vietnam combat veterans with PTSD responded to unpleasant images with greater negative emotionality (i.e., enhanced arousal and lower valence ratings) than those without the disorder and this effect was modified by the trauma-relatedness of the image with stronger effects for trauma-related images. In contrast, the 2 groups showed equivalent patterns of responses to pleasant images. Findings raise questions about the sensitivity of the International Affective Picture System rating protocol for the assessment of PTSD-related emotional numbing.

The effect of positive mood induction on emotional processing in euthymic individuals with bipolar disorder and controls

BACKGROUND

Many studies have used negative mood induction techniques to investigate the effect of emotional state on cognitive performance but positive mood induction paradigms have been used less frequently. The objective of this study was to investigate the effect of positive mood induction on emotional processing in euthymic individuals with bipolar disorder (BD) and controls.

METHOD

Previously, we reported that positive mood induction using a novel technique based on feedback produced a longer-lasting effect in euthymic individuals with BD than controls (Farmer et al. 2006). Here we report the effect of mood induction on two tests of emotional processing, the Affective Go/No-go test (AGNG) and the Cambridge Gamble task (CGT), on which BD patients in the manic phase differ in their performance from controls.

RESULTS

Following positive mood induction, bipolar cases exhibited a positive emotional bias on the AGNG and performed more slowly than controls on the CGT, particularly when making more difficult decisions.

CONCLUSIONS

These data confirm that positive mood induction is more effective in individuals with BD than controls. They also suggest that alterations in decision making and attentional biases occur even with transient and subtle changes in mood in bipolar disorder.

Direct effects of diazepam on emotional processing in healthy volunteers

RATIONALE

Pharmacological agents used in the treatment of anxiety have been reported to decrease threat relevant processing in patients and healthy controls, suggesting a potentially relevant mechanism of action. However, the effects of the anxiolytic diazepam have typically been examined at sedative doses, which do not allow the direct actions on emotional processing to be fully separated from global effects of the drug on cognition and alertness.

OBJECTIVES

The aim of this study was to investigate the effect of a lower, but still clinically effective, dose of diazepam on emotional processing in healthy volunteers.

MATERIALS AND METHODS

Twenty-four participants were randomised to receive a single dose of diazepam (5 mg) or placebo. Sixty minutes later, participants completed a battery of psychological tests, including measures of non-emotional cognitive performance (reaction time and sustained attention) and emotional processing (affective modulation of the startle reflex, attentional dot probe, facial expression recognition, and emotional memory). Mood and subjective experience were also measured.

RESULTS

Diazepam significantly modulated attentional vigilance to masked emotional faces and significantly decreased overall startle reactivity. Diazepam did not significantly affect mood, alertness, response times, facial expression recognition, or sustained attention.

CONCLUSIONS

At non-sedating doses, diazepam produces effects on attentional vigilance and startle responsivity that are consistent with its anxiolytic action. This may be an underlying mechanism through which benzodiazepines exert their therapeutic effects in clinical anxiety.

What aspects of emotional functioning are impaired in schizophrenia?

Disturbances in emotional functioning are a major cause of persistent functional disability in schizophrenia. However, it is not clear what specific aspects of emotional functioning are impaired. Some studies have indicated diminished experience of positive affect in individuals with schizophrenia, while others have not. The current study assessed emotional responses by 34 individuals with schizophrenia and 35 demographically matched healthy participants to 131 images sampling a wide range of emotional arousal and valence levels. Ratings of affective response elicited by individual images were highly correlated across the groups (r's>.90), indicating similar emotional experiences at the moment of stimulus exposure. However, the data did not indicate strong relationships between ratings of the emotional impact of the images and most measures of day-to-day emotional processing. These results demonstrate that individuals with schizophrenia report "normal" emotional responses to emotional stimuli, and thus suggests that deficits in emotional functioning associated with the disorder are likely to occur further downstream, and involve the effective integration of emotion and cognition for adaptive functioning in areas such as goal-setting, motivation, and memory.

Recognition of facial emotions among maltreated children with high rates of post-traumatic stress disorder

OBJECTIVE

The purpose of this study is to examine processing of facial emotions in a sample of maltreated children showing high rates of post-traumatic stress disorder (PTSD). Maltreatment during childhood has been associated independently with both atypical processing of emotion and the development of PTSD. However, research has provided little evidence indicating how high rates of PTSD might relate to maltreated children's processing of emotions.

METHOD

Participants' reaction time and labeling of emotions were measured using a morphed facial emotion identification task. Participants included a diverse sample of maltreated children with and without PTSD and controls ranging in age from 8 to 15 years. Maltreated children had been removed from their homes and placed in state custody following experiences of maltreatment. Diagnoses of PTSD and other disorders were determined through combination of parent, child, and teacher reports.

RESULTS

Maltreated children displayed faster reaction times than controls when labeling emotional facial expressions, and this result was most pronounced for fearful faces. Relative to children who were not maltreated, maltreated children both with and without PTSD showed enhanced response times when identifying fearful faces. There was no group difference in labeling of emotions when identifying different facial emotions.

CONCLUSIONS

Maltreated children show heightened ability to identify fearful faces, evidenced by faster reaction times relative to controls. This association between maltreatment and atypical processing of emotion is independent of PTSD diagnosis.

Discontinuities and cognitive changes in an exposure-based cognitive therapy for depression

Significant shifts or discontinuities in symptom course can mark points of transition and reveal important change processes. The authors investigated 2 patterns of change in depression-the rapid early response and a transient period of apparent worsening that the authors call a depression spike. Participants were 29 patients diagnosed with major depressive disorder who enrolled in an open trial of an exposure-based cognitive therapy. Hierarchical linear modeling revealed an overall cubic shape of symptom change and that both the rapid response and spike patterns predicted lower posttreatment depression. Patients wrote weekly narratives about their depression. Early narratives of rapid responders were coded as having more hope than those of nonrapid responders. The narratives of patients with a depression spike had more cognitive-emotional processing during this period of arousal than those without a spike. Findings are discussed in the context of cognitive-emotional processing theories in depression and anxiety disorders.

The subjective and cognitive effects of acute phenylalanine and tyrosine depletion in patients recovered from depression

Although there is evidence for the involvement of dopamine (DA) in unipolar depression, no published study has yet used the technique of acute phenylalanine and tyrosine depletion (APTD), a dietary intervention that selectively lowers DA synthesis, in order to investigate the role of DA in mood disturbance. Tyrosine and phenylalanine depleted and placebo amino acid drinks were administered to 20 patients recovered from depression in a double-blind, placebo-controlled, crossover design. Measures included subjective effects, Hamilton Depression Rating Scale scores, and a comprehensive battery of well-validated computerized cognitive tests. APTD induced a substantial reduction in the ratio of plasma tyrosine and phenylalanine to large neutral amino acids. However, relapse of depressive symptoms was not seen. Although performance on most cognitive tests was unaffected, there was a selective effect on decision-making, with APTD causing participants to bet significantly less. In conclusion, These results suggest a specific role for the involvement of DA in reward/punishment processing in humans. While APTD did not induce relapse in any participant, it did cause patients recovered from depression to show lowered sensitivity to reward in a gambling game. It is hypothesized that tests involving reward/punishment processing are preferentially affected by DA depletion, and that a more complete account of depression is likely to result from considering the roles played by serotonin, noradrenaline, and DA in mediating the various cognitive and clinical symptoms, including anhedonia.

Posttraumatic stress disorder and the nature of trauma

The role of psychological trauma (eg, rape, physical assaults, torture, motor vehicle accidents) as an etiological factor in mental disorders, anticipated as early as the 19th century by Janet, Freud, and Breuer, and more specifically during World War I and II by Kardiner, was "rediscovered" some 20 years ago in the wake of the psychological traumas inflicted by the Vietnam war and the discussion "in the open " of sexual abuse and rape by the women's liberation movement, 1980 marked a major turning point, with the incorporation of the diagnostic construct of posttraumatic stress disorder (PTSD) into the 3rd edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-III) and the definition of its main diagnostic criteria (reexperiencing of the traumatic event, avoidance of stimuli associated with the trauma, and symptoms of increased arousal). Initially described as resulting from a onetime severe traumatic incident, PTSD has now been shown to be triggered by chronic multiple traumas as well. This "state-of-the-art" article discusses past and current understanding of the disorder, with particular emphasis on the recent explosive developments in neuroimaging and other fields of the neurosciences that have highlighted the complex interrelationships between the psychological, psychiatric, biological, and neuroanatomical components of the disorder, and opened up entirely new therapeutic perspectives on how to help the victims of trauma overcome their past.

Posttraumatic stress disorder and the nature of trauma

The role of psychological trauma (eg, rape, physical assaults, torture, motor vehicle accidents) as an etiological factor in mental disorders, anticipated as early as the 19th century by Janet, Freud, and Breuer, and more specifically during World War I and II by Kardiner, was "rediscovered" some 20 years ago in the wake of the psychological traumas inflicted by the Vietnam war and the discussion "in the open " of sexual abuse and rape by the women's liberation movement, 1980 marked a major turning point, with the incorporation of the diagnostic construct of posttraumatic stress disorder (PTSD) into the 3rd edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-III) and the definition of its main diagnostic criteria (reexperiencing of the traumatic event, avoidance of stimuli associated with the trauma, and symptoms of increased arousal). Initially described as resulting from a onetime severe traumatic incident, PTSD has now been shown to be triggered by chronic multiple traumas as well. This "state-of-the-art" article discusses past and current understanding of the disorder, with particular emphasis on the recent explosive developments in neuroimaging and other fields of the neurosciences that have highlighted the complex interrelationships between the psychological, psychiatric, biological, and neuroanatomical components of the disorder, and opened up entirely new therapeutic perspectives on how to help the victims of trauma overcome their past.