Acute Angiotensin II Receptor Blockade Facilitates Parahippocampal Processing During Memory Encoding in High-Trait-Anxious Individuals

Background

Angiotensin II receptor blockers (ARBs) have been associated with preventing posttraumatic stress disorder symptom development and improving memory. However, the underlying neural mechanisms are poorly understood. This study investigated ARB effects on memory encoding and hippocampal functioning that have previously been implicated in posttraumatic stress disorder development.

Methods

In a double-blind randomized design, 40 high-trait-anxious participants (33 women) received the ARB losartan (50 mg) or placebo. At drug peak level, participants encoded images of animals and landscapes before undergoing functional magnetic resonance imaging, where they viewed the encoded familiar images and unseen novel images to be memorized and classified as animals/landscapes. Memory recognition was assessed 1 hour after functional magnetic resonance imaging. To analyze neural effects, whole-brain analysis, hippocampus region-of-interest analysis, and exploratory multivariate pattern similarity analysis were employed.

Results

ARBs facilitated parahippocampal processing. In the whole-brain analysis, losartan enhanced brain activity for familiar images in the parahippocampal gyrus (PHC), anterior cingulate cortex, and caudate. For novel images, losartan enhanced brain activity in the PHC only. Pattern similarity analysis showed that losartan increased neural stability in the PHC when processing novel and familiar images. However, there were no drug effects on memory recognition or hippocampal activation.

Conclusions

Given that the hippocampus receives major input from the PHC, our findings suggest that ARBs may modulate higher-order visual processing through parahippocampal involvement, potentially preserving intact memory input. Future research needs to directly investigate whether this effect may underlie the preventive effects of ARBs in the development of posttraumatic stress disorder.

Reduction of Aversive Learning Rates in Pavlovian Conditioning by Angiotensin II Antagonist Losartan: A Randomized Controlled Trial

BACKGROUND

Angiotensin receptor blockade has been linked to aspects of aversive learning and memory formation and to the prevention of posttraumatic stress disorder symptom development.

METHODS

We investigated the influence of the angiotensin receptor blocker losartan on aversive Pavlovian conditioning using a probabilistic learning paradigm. In a double-blind, randomized, placebo-controlled design, we tested 45 (18 female) healthy volunteers during a baseline session, after application of losartan or placebo (drug session), and during a follow-up session. During each session, participants engaged in a task in which they had to predict the probability of an electrical stimulation on every trial while the true shock contingencies switched repeatedly between phases of high and low shock threat. Computational reinforcement learning models were used to investigate learning dynamics.

RESULTS

Acute administration of losartan significantly reduced participants' adjustment during both low-to-high and high-to-low threat changes. This was driven by reduced aversive learning rates in the losartan group during the drug session compared with baseline. The 50-mg drug dose did not induce reduction of blood pressure or change in reaction times, ruling out a general reduction in attention and engagement. Decreased adjustment of aversive expectations was maintained at a follow-up session 24 hours later.

CONCLUSIONS

This study shows that losartan acutely reduces Pavlovian learning in aversive environments, thereby highlighting a potential role of the renin-angiotensin system in anxiety development.

Brain activity measured by functional brain imaging predicts breathlessness improvement during pulmonary rehabilitation

BACKGROUND

Chronic breathlessness in chronic obstructive pulmonary disease (COPD) is effectively treated with pulmonary rehabilitation. However, baseline patient characteristics predicting improvements in breathlessness are unknown. This knowledge may provide better understanding of the mechanisms engaged in treating breathlessness and help to individualise therapy. Increasing evidence supports the role of expectation (ie, placebo and nocebo effects) in breathlessness perception. In this study, we tested functional brain imaging markers of breathlessness expectation as predictors of therapeutic response to pulmonary rehabilitation, and asked whether D-cycloserine, a brain-active drug known to influence expectation mechanisms, modulated any predictive model.

METHODS

Data from 71 participants with mild-to-moderate COPD recruited to a randomised double-blind controlled experimental medicine study of D-cycloserine given during pulmonary rehabilitation were analysed (ID: NCT01985750). Baseline variables, including brain-activity, self-report questionnaires responses, clinical measures of respiratory function and drug allocation were used to train machine-learning models to predict the outcome, a minimally clinically relevant change in the Dyspnoea-12 score.

RESULTS

Only models that included brain imaging markers of breathlessness-expectation successfully predicted improvements in Dyspnoea-12 score (sensitivity 0.88, specificity 0.77). D-cycloserine was independently associated with breathlessness improvement. Models that included only questionnaires and clinical measures did not predict outcome (sensitivity 0.68, specificity 0.2).

CONCLUSIONS

Brain activity to breathlessness related cues is a strong predictor of clinical improvement in breathlessness over pulmonary rehabilitation. This implies that expectation is key in breathlessness perception. Manipulation of the brain's expectation pathways (either pharmacological or non-pharmacological) therefore merits further testing in the treatment of chronic breathlessness.

Trait anxiety is associated with hidden state inference during aversive reversal learning

Updating beliefs in changing environments can be driven by gradually adapting expectations or by relying on inferred hidden states (i.e. contexts), and changes therein. Previous work suggests that increased reliance on context could underly fear relapse phenomena that hinder clinical treatment of anxiety disorders. We test whether trait anxiety variations in a healthy population influence how much individuals rely on hidden-state inference. In a Pavlovian learning task, participants observed cues that predicted an upcoming electrical shock with repeatedly changing probability, and were asked to provide expectancy ratings on every trial. We show that trait anxiety is associated with steeper expectation switches after contingency reversals and reduced oddball learning. Furthermore, trait anxiety is related to better fit of a state inference, compared to a gradual learning, model when contingency changes are large. Our findings support previous work suggesting hidden-state inference as a mechanism behind anxiety-related to fear relapse phenomena.

Effects of Training Body-Related Interpretations on Panic-Related Cognitions and Symptoms

Background

Interpretation biases (IBs) are central in panic disorder, and there is rich evidence showing that these are correlated with and predictive of panic-relevant symptomatology. However, experimental studies are needed to examine the potential causal effects of IBs, as predicted by cognitive models.

Methods

Panic-related IBs were manipulated via a sentence-completion Cognitive Bias Modification-Interpretation (CBM-I) training. The sample included N = 112 healthy participants reporting moderate levels of fear of bodily sensations. Participants were randomly allocated to a positive, negative, or control CBM-I condition. To test the trainings' effect on panic-relevant cognitive processing, IBs were assessed via proximal and distal measures. Symptom provocation tasks were applied to test transfer to panic-relevant symptomatology.

Results

Results on the proximal measure showed that positive CBM-I led to more positive IBs compared to negative, and control training. Further, positive CBM-I led to more positive IBs on the distal measure as compared to negative CBM-I. However, there were no differential training effects on panic-related symptomatology triggered via the provocation tasks.

Conclusion

The findings indicate a limited generalization of the effects of CBM-I on IBs and panic-related symptoms. Potential means to improve generalization, such as applying more nuanced measures and combining CBM-I with psychoeducation are discussed.

The effect of D-cycloserine on brain processing of breathlessness over pulmonary rehabilitation - an experimental medicine study

Research Question

Pulmonary rehabilitation is the best treatment for chronic breathlessness in COPD but there remains an unmet need to improve efficacy. Pulmonary rehabilitation has strong parallels with exposure-based cognitive behavioural therapies (CBT), both clinically and in terms of brain activity patterns. The partial NMDA-receptor agonist, D-cycloserine has shown promising results in enhancing efficacy of CBT, thus we hypothesised that it would similarly augment the effects of pulmonary rehabilitation in the brain. Positive findings would support further development in phase 3 clinical trials.

Methods

72 participants with mild-to-moderate COPD were recruited to a double-blind pre-registered (ID:NCT01985750) experimental medicine study running parallel to a pulmonary rehabilitation course. Participants were randomised to 250 mg D-cycloserine or placebo, administered immediately prior to the first four sessions of pulmonary rehabilitation. Primary outcome measures were differences between D-cycloserine and placebo in brain activity in the anterior insula, posterior insula, anterior cingulate cortices, amygdala and hippocampus following completion of pulmonary rehabilitation. Secondary outcomes included the same measures at an intermediate time point and voxel-wise difference across wider brain regions. An exploratory analysis determined the interaction with breathlessness-anxiety.

Results

No difference between D-cycloserine and placebo groups was observed across the primary or secondary outcome measures. D-cycloserine was shown instead to interact with changes in breathlessness anxiety to dampen reactivity to breathlessness cues. Questionnaire and measures of respiratory function showed no group difference. This is the first study testing brain-active drugs in pulmonary rehabilitation. Rigorous trial methodology and validated surrogate end-points maximised statistical power.

Conclusion

Although increasing evidence supports therapeutic modulation of NMDA pathways to treat symptoms, we conclude that a phase 3 clinical trial of D-cycloserine would not be worthwhile.

Personalized cognitive training: Protocol for individual-level meta-analysis implementing machine learning methods

Accumulating evidence suggests that cognitive training may enhance well-being. Yet, mixed findings imply that individual differences and training characteristics may interact to moderate training efficacy. To investigate this possibility, the current paper describes a protocol for a data-driven individual-level meta-analysis study aimed at developing personalized cognitive training. To facilitate comprehensive analysis, this protocol proposes criteria for data search, selection and pre-processing along with the rationale for each decision. Twenty-two cognitive training datasets comprising 1544 participants were collected. The datasets incorporated diverse training methods, all aimed at improving well-being. These training regimes differed in training characteristics such as targeted domain (e.g., working memory, attentional bias, interpretation bias, inhibitory control) and training duration, while participants differed in diagnostic status, age and sex. The planned analyses incorporate machine learning algorithms designed to identify which individuals will be most responsive to cognitive training in general and to discern which methods may be a better fit for certain individuals.

Hydrocortisone as an adjunct to brief cognitive-behavioural therapy for specific fear: Endocrine and cognitive biomarkers as predictors of symptom improvement

BACKGROUND

Glucocorticoid (GC) administration prior to exposure-based cognitive-behavioural therapy (CBT) has emerged as a promising approach to facilitate treatment outcome in anxiety disorders. Further components relevant for improved CBT efficacy include raised endogenous GCs and reductions in information-processing biases to threat.

AIMS

To investigate hydrocortisone as an adjunct to CBT for spider fear and the modulating role of threat bias change and endogenous short-term and long-term GCs for treatment response.

METHODS

Spider-fearful individuals were randomized to receiving either 20 mg of hydrocortisone (n = 17) or placebo (n = 16) one hour prior to single-session predominantly computerised exposure-based CBT. Spider fear was assessed using self-report and behavioural approach measures at baseline, 1-day and 1-month follow-up. Threat processing was assessed at baseline and 1-day follow-up. Cortisol and cortisone were analysed from hair and saliva samples at baseline.

RESULTS/OUTCOMES

Self-report, behavioural and threat processing indices improved following CBT. Hydrocortisone augmentation resulted in greater improvement of self-report spider fear and stronger increase in speed when approaching a spider, but not on threat bias. Neither threat bias nor endogenous GCs predicted symptom change, and no interactive effects with hydrocortisone emerged. Preliminary evidence indicated higher hair cortisone as predictor of a stronger threat bias reduction.

CONCLUSIONS/INTERPRETATION

Our data extend earlier findings by suggesting that GC administration boosts the success of exposure therapy for specific fear even with a low-level therapist involvement. Future studies corroborating our result of a predictive hair GC relationship with threat bias change in larger clinical samples are needed.

Breathlessness in COPD: linking symptom clusters with brain activity

Background

Current models of breathlessness often fail to explain disparities between patients' experiences of breathlessness and objective measures of lung function. While a mechanistic understanding of this discordance has thus far remained elusive, factors such as mood, attention and expectation have all been implicated as important modulators of breathlessness. Therefore, we have developed a model to better understand the relationships between these factors using unsupervised machine learning techniques. Subsequently we examined how expectation-related brain activity differed between these symptom-defined clusters of participants.

Methods

A cohort of 91 participants with mild-to-moderate chronic obstructive pulmonary disease (COPD) underwent functional brain imaging, self-report questionnaires and clinical measures of respiratory function. Unsupervised machine learning techniques of exploratory factor analysis and hierarchical cluster modelling were used to model brain–behaviour–breathlessness links.

Results

We successfully stratified participants across four key factors corresponding to mood, symptom burden and two capability measures. Two key groups resulted from this stratification, corresponding to high and low symptom burden. Compared with the high symptom burden group, the low symptom burden group demonstrated significantly greater brain activity within the anterior insula, a key region thought to be involved in monitoring internal bodily sensations (interoception).

Conclusions

This is the largest functional neuroimaging study of COPD to date, and is the first to provide a clear model linking brain, behaviour and breathlessness expectation. Furthermore, it was possible to stratify participants into groups, which then revealed differences in brain activity patterns. Together, these findings highlight the value of multimodal models of breathlessness in identifying behavioural phenotypes and for advancing understanding of differences in breathlessness burden.

Towards individualised treatments for chronic breathlessness with functional neuroimaging: revealing the factors underlying the breathlessness experience in COPDhttps://bit.ly/3a8fXPt

Human perceptual learning is delayed by the N-methyl-D-aspartate receptor partial agonist D-cycloserine

BACKGROUND

The optimisation of learning has long been a focus of scientific research, particularly in relation to improving psychological treatment and recovery of brain function. Previously, partial N-methyl-D-aspartate agonists have been shown to augment reward learning, procedural learning and psychological therapy, but many studies also report no impact of these compounds on the same processes.

AIMS

Here we investigate whether administration of an N-methyl-D-aspartate partial agonist (D-cycloserine) modulates a previously unexplored process - tactile perceptual learning. Further, we use a longitudinal design to investigate whether N-methyl-D-aspartate-related learning effects vary with time, thereby providing a potentially simple explanation for apparent mixed effects in previous research.

METHODS

Thirty-four volunteers were randomised to receive one dose of 250 mg D-cycloserine or placebo 2 h before tactile sensitivity training. Tactile perception was measured using psychophysical methods before and after training, and 24/48 h later.

RESULTS

The placebo group showed immediate within-day tactile perception gains, but no further improvements between-days. In contrast, tactile perception remained at baseline on day one in the D-cycloserine group (no within-day learning), but showed significant overnight gains on day two. Both groups were equivalent in tactile perception by the final testing - indicating N-methyl-D-aspartate effects changed the timing, but not the overall amount of tactile learning.

CONCLUSIONS

In sum, we provide first evidence for modulation of perceptual learning by administration of a partial N-methyl-D-aspartate agonist. Resolving how the effects of such compounds become apparent over time will assist the optimisation of testing schedules, and may help resolve discrepancies across the learning and cognition domains.

D-cycloserine as adjunct to brief computerised CBT for spider fear: Effects on fear, behaviour, and cognitive biases

BACKGROUND AND OBJECTIVES

In anxiety disorders, cognitive behavioural therapy (CBT) improves information-processing biases such as implicit fear evaluations and avoidance tendencies, which predicts treatment response. Thus, these cognitive biases might constitute important treatment targets. This study investigated (i) whether information-processing biases could be changed following single-session computerised CBT for spider fear, and (ii) whether this effect could be augmented by administration of D-cycloserine (DCS).

METHODS

Spider-fearful individuals were randomized to receiving either 250 mg of DCS (n = 21) or placebo (n = 17). Three hours after drug administration, they received single-session computerized CBT, characterized by psychoeducation and exposure elements. Spider fear was assessed using self-report, behavioural, and information processing (Extrinsic Affective Simon Task & Approach Avoidance Task) measures at baseline (before drug administration), post-treatment, 1-day, and 1-month follow-up.

RESULTS

Linear mixed-effects analyses indicated significant improvements on self-report and behavioural spider fear indices following CBT, but not on cognitive bias measures. There was no evidence of an augmentation effect of DCS on any outcome. Cognitive bias measures at 1-day were not predictive of 1-month follow-up spider fear in adjusted linear regression analyses.

LIMITATIONS

Results might be biased by limited representativeness of the sample (high education and intelligence, largely Caucasian ethnicity, young age). The study was also only powered for detection of medium-sized DCS effects.

CONCLUSIONS

These findings do not provide evidence for information-processing biases relating to treatment outcome following computerised CBT for spider fear or augmentation with DCS.

Cognitive Vulnerability in the Context of Panic: Assessment of Panic-Related Associations and Interpretations in Individuals with Varying Levels of Anxiety Sensitivity

Background

Cognitive models of panic disorder (PD) highlight the role of panic-related associations and interpretations. However, results are mixed and rely on specific measures. This study examined panic-related associations and interpretations using established and new paradigms in individuals varying on anxiety sensitivity (AS).

Methods

Associations were measured using a priming task and a novel Single Target Implicit Association Test (STIAT); interpretations were assessed using the Interpretation Bias Questionnaire (IBQ) and a novel Scrambled Sentences Task (SST). Symptoms were assessed via a provocation task (Straw Breathing Task, SBT).

Results

Panic-related interpretations correlated with AS and other PD-related measures. Of the association tasks, only the priming task correlated with one of the other PD-related measures. Panic-related interpretations assessed via the SST, but not priming, STIAT, and IBQ, predicted SBT reactivity. The relationship between AS and SBT reactivity was mediated by panic-related interpretations.

Conclusions

Our data provide support for panic-related interpretations as an important cognitive mechanism.

Neurocognitive processes in d-cycloserine augmented single-session exposure therapy for anxiety: A randomized placebo-controlled trial

Drugs targeting N-methyl-d-aspartate (NMDA) receptors and the ability to learn new associations have been proposed as adjunct treatments to boost the success of exposure therapy for anxiety disorders. However, the effects of the NMDA partial agonist d-cycloserine on psychological treatment have been mixed. We investigated potential neurocognitive mechanisms underlying the clinical effects of d-cycloserine-augmented exposure, to inform the optimal combination of this and similar agents with psychological treatment. Panic disorder patients were randomised to single-dose d-cycloserine (250 mg; N = 17) or matching placebo (N = 16) 2hrs before one session of exposure therapy. Neurocognitive markers were assessed one day after treatment, including reaction-time based threat bias for fearful faces (primary outcome) and amygdala response to threat (secondary outcome). Clinical symptom severity was measured the day before and after treatment, and at 1- and 6-months follow-up (secondary outcome). d-cycloserine was associated with greater clinical recovery at 1-month follow-up than placebo (d-cyloserine 71% vs placebo 25%), with the placebo group matching the clinical gains of the d-cycloserine group during 6-months follow-up (d-cycloserine 71% vs placebo 44%). One day after treatment, threat bias for fearful faces and amygdala threat response was lower in the drug compared to placebo group. Lower amygdala magnitude predicted greater clinical improvement during follow-up across groups. While this experimental study is of a preliminary nature due to the limited sample size, these findings highlight a neurocognitive potential mechanism by which d-cycloserine may exert its augmentative effects on psychological treatment and bring forward a marker that may help understand and facilitate development of combination treatments for anxiety. (d-cycloserine Augmented CBT for Panic Disorder; clinicaltrials.gov; NCT01680107).

Angiotensin involvement in trauma processing-exploring candidate neurocognitive mechanisms of preventing post-traumatic stress symptoms

The angiotensin-II antagonist losartan is a promising candidate that has enhanced extinction in a post-traumatic stress disorder (PTSD) animal model and was related to reducing PTSD symptom development in humans. Here, we investigate the neurocognitive mechanisms underlying these results, testing the effect of losartan on data-driven and contextual processing of traumatic material, mechanisms proposed to be relevant for PTSD development. In a double-blind between-subject design, 40 healthy participants were randomised to a single oral dose of losartan (50 mg) or placebo, 1 h before being exposed to distressing films as a trauma analogue while heart rate (HR) was measured. Peritraumatic processing was investigated using blurry picture stimuli from the films, which transformed into clear images. Data-driven processing was measured by the level of blurriness at which contents were recognised. Contextual processing was measured as the amount of context information retrieved when describing the pictures' contents. Negative-matched control images were used to test perceptual processing of peripheral trauma-cues. Post-traumatic stress symptoms were assessed via self-report questionnaires after analogue trauma and an intrusion diary completed over 4 days following the experiment. Compared to placebo, losartan facilitated contextual processing and enhanced detail perception in the negative-match pictures. During the films, the losartan group recorded lower HR and higher HR variability, reflecting lower autonomic stress responses. We discuss potential mechanisms of losartan in preventing PTSD symptomatology, including the role of reduced arousal and increased contextual processing during trauma exposure, as well as increased threat-safety differentiation when encountering peripheral trauma-cues in the aftermaths of traumatic events.

A lack of differentiation in amygdala responses to fearful expression intensity in panic disorder patients

Patients with panic disorder show abnormalities in threat processing and regulation, both on a behavioural and neural level. Better understanding of the underlying mechanisms could help to develop new treatment strategies. In this study, we investigated brain region activation in 18 patients with untreated panic disorder (PD) and 17 healthy controls (HC) during the processing of emotional faces with fearful, happy and neutral expressions, using functional MRI. The intensity of the expressions was either prototypically high, medium or low. PD patients showed significantly increased activity in the dorso-medial prefrontal cortex (dmPFC) in response to faces in general and specifically for happy faces. While HC showed a decreased amygdala response to medium/low fearful versus high fearful faces, this effect was not present in PD: amygdala activation was stable across all fearful faces in this group. Psycho-physiological interaction analyses indicated more negative connectivity between the amygdala and prefrontal areas in the PD group during the task. Amygdala activation in panic patients appears to be less sensitive to decreasing intensities of fearful facial expressions and salience monitoring areas were less active during fearful faces in general in this group. This suggests PD patients might avoid more extensive processing of fearful faces.

The Effects of the Angiotensin II Receptor Antagonist Losartan on Appetitive Versus Aversive Learning: A Randomized Controlled Trial

BACKGROUND

Exposure therapy is a first-line treatment for anxiety disorders but remains ineffective in a large proportion of patients. A proposed mechanism of exposure involves inhibitory learning whereby the association between a stimulus and an aversive outcome is suppressed by a new association with an appetitive or neutral outcome. The blood pressure medication losartan augments fear extinction in rodents and may have similar synergistic effects on human exposure therapy, but the exact cognitive mechanisms underlying these effects remain unknown.

METHODS

We used a reinforcement learning paradigm with compound rewards and punishments to test the prediction that losartan augments learning from appetitive relative to aversive outcomes. In a double-blind parallel design, healthy volunteers were randomly assigned to single-dose losartan (50 mg) (n = 28) versus placebo (n = 25). Participants then performed a reinforcement learning task, which simultaneously probes appetitive and aversive learning. Participant choice behavior was analyzed using both a standard reinforcement learning model and analysis of choice switching behavior.

RESULTS

Losartan significantly reduced learning rates from aversive events (losses) when participants were first exposed to the novel task environment, while preserving learning from positive outcomes. The same effect was seen in choice switching behavior.

CONCLUSIONS

This study shows that losartan enhances learning from positive relative to negative events. This effect may represent a computationally defined neurocognitive mechanism by which the drug could enhance the effect of exposure in clinical populations.

Early effects of exposure-based cognitive behaviour therapy on the neural correlates of anxiety

Exposure-based cognitive-behaviour therapy (CBT) for anxiety disorders is an effective intervention, but the brain mechanisms driving recovery are largely unknown. In this experimental medicine study, we investigated to what degree CBT affects neural markers of anxiety at an early stage of treatment, to identify dynamic mechanistic changes which might be crucial in the process of recovery as opposed to those seen following full treatment completion. In a randomised controlled trial, unmedicated patients with panic disorder either received four weekly sessions of exposure-based CBT (N = 14) or were allocated to a waiting group (N = 14). Symptom severity was measured before and after the intervention. During functional magnetic resonance imaging (fMRI), patients performed an emotion regulation task, either viewing negative images naturally, or intentionally down-regulating negative affect using previously taught strategies. Four-session CBT led to marked reductions in symptoms and 71% of patients reached recovery status (versus 7% in the control group). This intervention normalised brain hyperactivation previously seen in panic disorder, particularly in areas linked to threat monitoring, fear memory, and maladaptive emotion regulation, such as amygdala, dorsomedial and dorsolateral prefrontal cortex, and temporal gyrus. Our findings suggest that optimal treatment doses for panic disorder might be much lower than previously thought. Furthermore, this is the first study to show that neural markers of anxiety change very early during CBT, highlighting potential neural mechanisms that might drive clinical recovery. Such knowledge is important for the development of more compact combination treatments targeting these mechanisms more effectively. (Neural Effects of Cognitive-behaviour Therapy in Panic Disorder; clinicaltrials.gov; NCT03251235).

Single-dose hydrocortisone administration does not enhance motor sequence learning or reward learning in humans

Despite its physiological and clinical relevance, the influence of hydrocortisone on specific kinds of learning remains relatively unexplored. We measured the effect of hydrocortisone on motor sequence and reward learning under non-stress conditions. For the study, 54 healthy young volunteers were randomly assigned to a dose of 20 mg hydrocortisone versus placebo. Participants performed two well-defined learning tasks. Hydrocortisone did not affect motor sequence or reward learning.

Investigating d-cycloserine as a potential pharmacological enhancer of an emotional bias learning procedure

The partial N-methyl-D-aspartate receptor agonist d-cycloserine may enhance psychological therapies. However, its exact mechanism of action is still being investigated. Cognitive bias modification techniques allow isolation of cognitive processes and thus investigation of how they may be affected by d-cycloserine. We used a cognitive bias modification paradigm targeting appraisals of a stressful event, Cognitive Bias Modification-Appraisal, to investigate whether d-cycloserine enhanced the modification of appraisal, and whether it caused greater reduction in indices of psychopathology. Participants received either 250 mg of d-cycloserine ( n=19) or placebo ( n=19). As a stressor task, participants recalled a negative life event, followed by positive Cognitive Bias Modification-Appraisal training. Before and after Cognitive Bias Modification-Appraisal, appraisals and indices of psychopathology related to the stressor were assessed. Cognitive Bias Modification-Appraisal successfully modified appraisals, but d-cycloserine did not affect appraisals post-training. There were no post-training group differences in frequency of intrusions. Interestingly, d-cycloserine led to a greater reduction in distress and impact on state mood from recalling the event, and lower distress post-training was associated with fewer intrusions. Therefore, d-cycloserine may affect emotional reactivity to recalling a negative event when combined with induction of a positive appraisal style, but via a mechanism other than enhanced learning of the appraisal style.

Stratification of MDD and GAD patients by resting state brain connectivity predicts cognitive bias

Patients with Generalized Anxiety Disorder (GAD) and Major Depressive Disorder (MDD) show between-group comorbidity and symptom overlap, and within-group heterogeneity. Resting state functional connectivity might provide an alternate, biologically informed means by which to stratify patients with GAD or MDD. Resting state functional magnetic resonance imaging data were acquired from 23 adults with GAD, 21 adults with MDD, and 27 healthy adult control participants. We investigated whether within- or between-network connectivity indices from five resting state networks predicted scores on continuous measures of depression and anxiety. Successful predictors were used to stratify participants into two new groups. We examined whether this stratification predicted attentional bias towards threat and whether this varied between patients and controls. Depression scores were linked to elevated connectivity within a limbic network including the amygdala, hippocampus, VMPFC and subgenual ACC. Patients with GAD or MDD with high limbic connectivity showed poorer performance on an attention-to-threat task than patients with low limbic connectivity. No parallel effect was observed for control participants, resulting in an interaction of clinical status by resting state group. Our findings provide initial evidence for the external validity of stratification of MDD and GAD patients by functional connectivity markers. This stratification cuts across diagnostic boundaries and might valuably inform future intervention studies. Our findings also highlight that biomarkers of interest can have different cognitive correlates in individuals with versus without clinically significant symptomatology. This might reflect protective influences leading to resilience in some individuals but not others.

Differential activation of the frontal pole to high vs low calorie foods: The neural basis of food preference in Anorexia Nervosa?

Neuroimaging studies in anorexia nervosa (AN) suggest that altered food reward processing may result from dysfunction in both limbic reward and cortical control centers of the brain. This fMRI study aimed to index the neural correlates of food reward in a subsample of individuals with restrictive AN: twelve currently ill, fourteen recovered individuals and sixteen healthy controls. Participants were shown pictures of high and low-calorie foods and asked to evaluate how much they wanted to eat each one following a four hour fast. Whole-brain task-activated analysis was followed by psychophysiological interaction analysis (PPI) of the amygdala and caudate. In the AN group, we observed a differential pattern of activation in the lateral frontal pole: increasing following presentation of high-calorie stimuli and decreasing in during presentation of low-calorie food pictures, the opposite of which was seen in the healthy control (HC) group. In addition, decreased activation to food pictures was observed in somatosensory regions in the AN group. PPI analyses suggested hypo-connectivity in reward pathways, and between the caudate and both somatosensory and visual processing regions in the AN group. No significant between-group differences were observed between the recovered group and the currently ill and healthy controls in the PPI analysis. Taken together, these findings further our understanding of the neural processes which may underpin the avoidance of high-calorie foods in those with AN and might exacerbate the development of compulsive weight-loss behavior, despite emaciation.

The NMDA receptor partial agonist d-cycloserine does not enhance motor learning

RATIONALE

There has recently been increasing interest in pharmacological manipulations that could potentially enhance exposure-based cognitive behaviour therapy for anxiety disorders. One such medication is the partial NMDA agonist d-cycloserine. It has been suggested that d-cycloserine enhances cognitive behaviour therapy by making learning faster. While animal studies have supported this view of the drug accelerating learning, evidence in human studies has been mixed. We therefore designed an experiment to measure the effects of d-cycloserine on human motor learning.

METHODS

Fifty-four healthy human volunteers were randomly assigned to a single dose of 250mg d-cycloserine versus placebo in a double-blind design. They then performed a motor sequence learning task.

RESULTS

D-cycloserine did not increase the speed of motor learning or the overall amount learnt. However, we noted that participants on d-cycloserine tended to respond more carefully (shifting towards slower, but more correct responses).

CONCLUSION

The results suggest that d-cycloserine does not exert beneficial effects on psychological treatments via mechanisms involved in motor learning. Further studies are needed to clarify the influence on other cognitive mechanisms.

Four-corner fusion: comparison of patient satisfaction and functional outcome of conventional K-wire technique vs. a new locking plate

BACKGROUND

Four-corner fusion is a standard procedure for advanced carpal collapse. Several operative techniques and numerous implants for osseous fixation have been described. Recently, a specially designed locking plate (Aptus©, Medartis, Basel, Switzerland) was introduced. The purpose of this study was to compare functional results after osseous fixation using K-wires (standard of care, SOC) with four-corner fusion and locking plate fixation.

METHODS

21 patients who underwent four-corner fusion in our institution between 2008 and 2013 were included in a retrospective analysis. In 11 patients, osseous fixation was performed using locking plates whereas ten patients underwent bone fixation with conventional K-wires. Outcome parameters were functional outcome, osseous consolidation, patient satisfaction (DASH- and Krimmer Score), pain and perioperative morbidity and the time until patients returned to daily work. Patients were divided in two groups and paired t-tests were performed for statistical analysis.

RESULTS

No implant related complications were observed. Osseous consolidation was achieved in all cases. Differences between groups were not significant regarding active range of motion (AROM), pain and function. Overall patient satisfaction was acceptable in all cases; differences in the DASH questionnaire and the Krimmer questionnaire were not significant. One patient of the plate group required conversion to total wrist arthrodesis without implant-related complications.

CONCLUSION

Both techniques for four-corner fusion have similar healing rates. Using the more expensive locking implant avoids a second operation for K-wire removal, but no statistical differences were detected in functional outcome as well as in patient satisfaction when compared to SOC.

Effective emotion regulation strategies improve fMRI and ECG markers of psychopathology in panic disorder: implications for psychological treatment action

Impairments in emotion regulation are thought to have a key role in the pathogenesis of anxiety disorders, but the neurobiological underpinnings contributing to vulnerability remain poorly understood. It has been a long-held view that exaggerated fear is linked to hyperresponsivity of limbic brain areas and impaired recruitment of prefrontal control. However, increasing evidence suggests that prefrontal-cortical networks are hyperactive during threat processing in anxiety disorders. This study directly explored limbic-prefrontal neural response, connectivity and heart-rate variability (HRV) in patients with a severe anxiety disorder during incidental versus intentional emotion regulation. During 3 Tesla functional magnetic resonance imaging, 18 participants with panic disorder and 18 healthy controls performed an emotion regulation task. They either viewed negative images naturally (Maintain), or they were instructed to intentionally downregulate negative affect using previously taught strategies of cognitive reappraisal (Reappraisal). Electrocardiograms were recorded throughout to provide a functional measure of regulation and emotional processing. Compared with controls, patients showed increased neural activation in limbic-prefrontal areas and reduced HRV during incidental emotion regulation (Maintain). During intentional regulation (Reappraisal), group differences were significantly attenuated. These findings emphasize patients' ability to regulate negative affect if provided with adaptive strategies. They also bring prefrontal hyperactivation forward as a potential mechanism of psychopathology in anxiety disorders. Although these results challenge models proposing impaired allocation of prefrontal resources as a key characteristic of anxiety disorders, they are in line with more recent neurobiological frameworks suggesting that prefrontal hyperactivation might reflect increased utilisation of maladaptive regulation strategies quintessential for anxiety disorders.

Different neural and cognitive response to emotional faces in healthy monozygotic twins at risk of depression

BACKGROUND

Negative cognitive bias and aberrant neural processing of emotional faces are trait-marks of depression. Yet it is unclear whether these changes constitute an endophenotype for depression and are also present in healthy individuals with hereditary risk for depression.

METHOD

Thirty healthy, never-depressed monozygotic (MZ) twins with a co-twin history of depression (high risk group: n = 13) or without co-twin history of depression (low-risk group: n = 17) were enrolled in a functional magnetic resonance imaging (fMRI) study. During fMRI, participants viewed fearful and happy faces while performing a gender discrimination task. After the scan, they were given a faces dot-probe task, a facial expression recognition task and questionnaires assessing mood, personality traits and coping strategies.

RESULTS

High-risk twins showed increased neural response to happy and fearful faces in dorsal anterior cingulate cortex (ACC), dorsomedial prefrontal cortex (dmPFC), pre-supplementary motor area and occipito-parietal regions compared to low-risk twins. They also displayed stronger negative coupling between amygdala and pregenual ACC, dmPFC and temporo-parietal regions during emotional face processing. These task-related changes in neural responses in high-risk twins were accompanied by impaired gender discrimination performance during face processing. They also displayed increased attention vigilance for fearful faces and were slower at recognizing facial expressions relative to low-risk controls. These effects occurred in the absence of differences between groups in mood, subjective state or coping.

CONCLUSIONS

Different neural response and functional connectivity within fronto-limbic and occipito-parietal regions during emotional face processing and enhanced fear vigilance may be key endophenotypes for depression.

Predicting rapid response to cognitive-behavioural treatment for panic disorder: the role of hippocampus, insula, and dorsolateral prefrontal cortex

Although cognitive-behavioural therapy (CBT) is an effective first-line intervention for anxiety disorders, treatments remain long and cost-intensive, difficult to access, and a subgroup of patients fails to show any benefits at all. This study aimed to identify functional and structural brain markers that predict a rapid response to CBT. Such knowledge will be important to establish the mechanisms underlying successful treatment and to develop more effective, shorter interventions. Fourteen unmedicated patients with panic disorder underwent 3 T functional and structural magnetic resonance imaging (MRI) before receiving four sessions of exposure-based CBT. Symptom severity was measured before and after treatment. During functional MRI, patients performed an emotion regulation task, either viewing negative images naturally, or intentionally down-regulating negative affect by using previously taught strategies of cognitive reappraisal. Structural MRI images were analysed including left and right segmentation and volume estimation. Improved response to brief CBT was predicted by increased pre-treatment activation in bilateral insula and left dorsolateral prefrontal cortex (dlPFC) during threat processing, as well as increased right hippocampal gray matter volume. Previous work links these regions to improved threat processing and fear memory activation, suggesting that the activation of such mechanisms is crucial for exposure-based CBT to be effective.

Paradoxical effects of short-term antidepressant treatment in fMRI emotional processing models in volunteers with high neuroticism

BACKGROUND

Short-term antidepressant administration has been reported to decrease amygdala response to threat in healthy volunteers and depressed patients. Neuroticism (N) is a risk factor for depression but has also been associated with slow or incomplete remission with antidepressant drug treatment. Our aim was to investigate early selective serotonin reuptake inhibitor (SSRI) administration neural effects on implicit processing of fearful facial expressions in volunteers with high levels of N.

METHOD

Highly neurotic subjects received 20 mg/day citalopram versus placebo for 7 days in a double-blind, between-groups design. On the last day haemoperfusion and functional magnetic resonance imaging (fMRI) data during a gender discrimination task with fearful and happy faces were acquired. A control group of non-neurotic volunteers was also tested.

RESULTS

High-N volunteers had reduced responses to threatening facial expressions across key neural circuits compared to low-N volunteers. SSRI treatment was found to elevate resting perfusion in the right amygdala, increase bilateral amygdalae activation to positive and negative facial expressions and increase activation to fearful versus happy facial expressions in occipital, parietal, temporal and prefrontal cortical areas.

CONCLUSIONS

These results suggest that 7 days of SSRI administration can increase neural markers of fear reactivity in subjects at the high end of the N dimension and may be related to early increases in anxiety and agitation seen early in treatment. Such processes may be involved in the later therapeutic effects through decreased avoidance and increased learning about social 'threat' cues.

Optimizing the ingredients for imagery-based interpretation bias modification for depressed mood: is self-generation more effective than imagination alone?

Negative interpretation is thought to be crucial in the development and maintenance of depression. Recently developed cognitive bias modification paradigms, intending to change these biases towards a more optimistic interpretation tendency (CBM-I), seem to offer new promising implications for cognitive therapy innovation. This study aimed to increase our knowledge of the underlying mechanisms of action of imagery-based CBM-I in the context of depressed mood. We therefore compared the efficacy of CBM-I requiring participants to imagine standardized positive resolutions to a novel, more active training version that required participants to generate the positive interpretations themselves. Fifty-four participants were randomly allocated to (1) standardized CBM-I, (2) self-generation CBM-I or (3) a control group. Outcome measures included self-report mood measures and a depression-related interpretation bias measure. Both positive training variants significantly increased the tendency to interpret fresh ambiguous material in an optimistic manner. However, only the standardized imagery CBM-I paradigm positively influenced mood.

Intrusive images and voluntary memory for affective pictures: contextualization and dual-task interference

BACKGROUND AND OBJECTIVES

The present study addressed the role of context information and dual-task interference during the encoding of negative pictures on intrusion development and voluntary recall.

METHODS

Healthy participants were shown negative pictures with or without context information. Pictures were either viewed alone or concurrently with a visuospatial or verbal task. Participants reported their intrusive images of the pictures in a diary. At follow-up, perceptual and contextual memory was tested.

RESULTS

Participants in the context group reported more intrusive images and perceptual voluntary memory than participants in the no context group. No effects of the concurrent tasks were found on intrusive image frequency, but perceptual and contextual memory was affected according to the cognitive load of the task.

LIMITATIONS

The analogue method cannot be generalized to real-life trauma and the secondary tasks may differ in cognitive load.

CONCLUSIONS

The findings challenge a dual memory model of PTSD but support an account in which retrieval strategy, rather than encoding processes, accounts for the experience of involuntary versus voluntary recall.

Cognitive-behavioural therapy reduces unwanted thought intrusions in generalized anxiety disorder

BACKGROUND AND OBJECTIVES

Voluntary attempts to suppress certain thoughts can paradoxically increase their intrusive return. Particular impairments in thought suppression are thought to be key mechanisms in the pathogenesis of mental disorders. To assess the role of this processing bias in the maintenance of generalized anxiety disorder (GAD), we investigated whether it is susceptible to cognitive-behavioural treatment (CBT).

METHODS

22 GAD patients and 22 healthy controls (HC) were tested twice within 15 weeks, with patients receiving CBT in between. A subset of patients was additionally tested while waiting for treatment to control for retest effects. Using a mental control paradigm, we measured intrusion frequency during the voluntary suppression of thoughts related to (a) the individual main worry topic, (b) a negative non-worry topic, and (c) a neutral topic. Self-reported worry was measured before and after treatment, and at 6-months follow-up.

RESULTS

Compared to HC, GAD showed specifically more worry-related intrusions. CBT reduced this bias to a healthy level, over and above mere test-retest effects.

LIMITATIONS

This study could not clarify whether the demonstrated effect mediates other changes, or how it relates to other cognitive biases in GAD.

CONCLUSIONS

The results indicate that thought suppression processes are not only impaired in GAD, but that the impairment is specific to the patients' worries, and that it can be successfully targeted by CBT. This highlights the importance of thought suppression processes in the maintenance of GAD.

Acute antidepressant drug administration and autobiographical memory recall: a functional magnetic resonance imaging study

Antidepressants affect memory and neural responses to emotionally valenced stimuli in healthy volunteers. However, it is unclear whether this extends to autobiographical memory for personally experienced events. The current study investigated the effects of acute administration of the antidepressant reboxetine on emotional autobiographical retrieval in healthy volunteers (14 men, 10 women). Functional magnetic resonance imaging was used in a double-blind between-groups investigation with reboxetine (4 mg) and placebo. Consistent with previous reports using lab-based stimuli, neural activation in the processing of positive versus negative memories was reduced following reboxetine compared with placebo in the left frontal lobe (extending into the insula) and the right superior temporal gyrus. This was paired with increased memory speed in volunteers given reboxetine versus placebo. The effect of reboxetine on emotional memory extends to recall of personally experienced events. Such effects may be relevant to the cognitive improvements found with recovery from depression and with the mechanism of action of contemporary antidepressant drugs.

Analogue trauma results in enhanced encoding of threat information at the expense of neutral information

This study investigated whether trauma-related stimuli are preferentially processed at the expense of ongoing processing of neutral stimuli. Participants in the experimental group viewed negative pictures (Trauma) as an analogue trauma induction. Participants in the control group viewed visually similar neutral pictures (Neutral Match). In a Rapid Serial Visual Presentation (RSVP) task participants identified two target pictures. The first target (T1) was a neutral picture, whereas the second target (T2) was a familiar negative or neutral picture or a new neutral or negative picture. In line with hypotheses, only participants in the experimental group showed preferential processing of Trauma pictures. In the experimental group, negative T2 impaired the identification of (neutral) T1 if the T2 immediately followed the T1 in the RSVP stream. The results are consistent with a processing priority of trauma-related information, apparently at the expense of the ongoing processing of neutral information.

Treatment sensitivity of implicit threat evaluation, avoidance tendency and visual working memory bias in specific phobia

Cognitive theories of anxiety postulate that negative processing biases play a causal role in the pathogenesis of a disorder, while a normalisation of bias drives recovery. To test these assumptions it is essential to investigate whether biases seen in anxiety are treatment-sensitive, or whether they instead represent enduring vulnerability factors. Twenty-nine spider fearfuls were tested before and after brief cognitive-behaviour therapy (CBT), with half of them additionally being tested before a waiting period to control for retest effects. Using three cognitive bias tasks, we measured implicit threat evaluation (Extrinsic Affective Simon Task), avoidance tendency (Approach-Avoidance Task), and working memory for threat. CBT significantly enhanced negative implicit evaluation and avoidance. This indicates that these cognitive biases are no stable risk factors and provides further evidence for their potential key role in the development and remission of anxiety.

Outbreak of Salmonella Montevideo associated with a dietary food supplement flagged in the Rapid Alert System for Food and Feed (RASFF) in Germany, 2010

In March 2010 the Rapid Alert System for Food and Feed (RASFF) was used to inform about Salmonella Montevideo in a herbal food supplement, formulated in capsules, distributed under a Dutch label in Germany. Simultaneous to the first RASFF notice, in the last two weeks of March 2010 an unusual number of 15 infections with S. Montevideo was notified within the electronic reporting system for infectious diseases at the Robert Koch Institute. Adult women (median age: 43, range: 1-90 years) were mainly affected. An outbreak was suspected and the food supplement hypothesised to be its vehicle. Cases were notified from six federal states throughout Germany, which required efficient coordination of information and activities. A case-control study (n=55) among adult women showed an association between consumption of the specific food supplement and the disease (odds ratio (OR): 27.5, 95% confidence interval (CI): 3.1-infinity, p-value=0.002). Restricting the case-control study to the period when the outbreak peaked (between 29 March and 11 April 2010) resulted in an OR of 43.5 (95% CI: 4.8-infinity, p-value=0.001). Trace-back of the supplement's main ingredient, hemp seed flour, and subsequent microbiological testing by pulsed-field gel electrophoresis supported its likely role in transmission. This outbreak investigation illustrates that information from RASFF may aid in hypothesis generation in outbreak investigations, though likely late in the outbreak.

Outbreak of Salmonella Montevideo associated with a dietary food supplement flagged in the Rapid Alert System for Food and Feed (RASFF) in Germany, 2010

Binary file ES_Abstracts_Final_ECDC.txt matches

Attentional bias in untreated panic disorder

The role of attentional biases in panic disorder has been well characterised. However, recent studies suggest an important effect of antidepressant and anxiolytic drugs on cognitive bias and most studies have included medicated patients in their sample. This study therefore examined cognitive bias in an untreated sample of participants with panic disorder (PD). A sample of 23 untreated participants with panic disorder with or without agoraphobia (PPD) and 22 healthy controls (HC) were tested with a Facial Expression Recognition task featuring different emotional intensities, a Faces Dot Probe task, a Self Beliefs task and an Emotional Stroop task. PPD showed exaggerated attentional biases to negative face and word stimuli in two different paradigms and endorsed more panic-related and negative self-attributions. They also showed enhanced perception of facial expressions of sadness. These tasks are sensitive to cognitive bias in a community-based sample of untreated PD participants. Attentional biases in panic disorder cannot be explained by the use of medication in this group and may therefore play a critical role in the underlying pathogenesis of the disorder.

[Inappropriate lactation syndrome in goats--case collection and experiences with mastectomy]

OBJECTIVE

Hobby keeping of goats and sheep confronts veterinarians with new challenges that rarely have to be faced in livestock husbandry. During the last five years five goats were presented to the Clinic for Animal Reproduction, Faculty of Veterinary Medicine, Freie Universität Berlin, Germany, with inappropriate lactation syndrome. Four of these animals had been previously treated with cabergoline without enduring success. According to the request of the owners (informed consent) and the clinical severity of the cases, a mastectomy was performed in all five animals.

MATERIAL AND METHODS

Surgery was performed under general anaesthesia using ketamine and xylazine, and with the patients in a recumbent position.

RESULTS

Mastectomy in small ruminants requires knowledge of the anatomy of the udder and the possible positions of the supplying blood vessels. Our patients displayed a variety of dispositions of the Vena epigastrica caudalis superficialis. Special attention should be paid to a careful and blunt dissection of the mammary gland, and immediate control of haemorrhage, to maintain a clear view on the anatomic structures. Furthermore, dissection of the glandular tissue should be strictly avoided to prevent milk contamination of the surgical area. A sufficient skin flap has to be left to cover the surgical area after removal of the udder.

CONCLUSION AND CLINICAL RELEVANCE

Even though udder amputation appears to be a radical and high-risk procedure, all five goats survived the surgery. The wound healing occurred in a reasonable time without any severe complications. In goats that are kept as "hobby animals" and in which an inappropriate lactation syndrome cannot be treated conservatively, mastectomy is a reasonable and promising therapy.

Lactatio falsa bei der Ziege – Fallsammlung und Erfahrungen mit der Amputation des Gesäuges

Gegenstand: Die Haltung von Schafen und Ziegen als Hobbytiere konfrontiert Tierärzte mitunter mit Problemen, die bei einer reinen Nutztierhaltung eher selten vorkommen. In den letzten 5 Jahren wurden der Tierklinik für Fortpflanzung der FU Berlin fünf Ziegen aus Hobbyhaltungen mit rezidivierender Lactatio falsa vorgestellt. Vier Tiere waren in der Vergangenheit bereits mit Cabergolin mit ausbleibendem oder nur kurzfristigem Erfolg behandelt worden. Aufgrund der Größe des Euters wurde auf Wunsch der Besitzer bei allen fünf Ziegen eine Euteramputation vorgenommen. Material und Methoden: Der operative Eingriff erfolgte unter Allgemeinanästhesie mit Ketamin und Xylazin in Rückenlage der Patienten. Ergebnisse: Die durchgeführte Anästhesie erwies sich für den Eingriff als geeignet. Die Mastektomie bei Ziegen erfordert spezielle Kenntnisse hinsichtlich der Anatomie der Milchdrüse und ihrer versorgenden Gefäße. Bei den fünf Patienten war eine teils unterschiedliche Anlage der Vena epigastrica caudalis superficialis festzustellen. Bei der Operation zu beachten sind insbesondere das vorsichtige und stumpfe Präparieren und eine schnelle Blutstillung, um ein übersicht - liches Operationsfeld zu erhalten. Die Eröffnung von Zisternen oder Drüsengewebe sollte vermieden werden, damit keine Milch austritt, da daraus Wundheilungsstörungen entstehen könnten. Ein ausreichender Hautlappen für den späteren Wundverschluss muss belassen werden. Schlussfolgerung und klinische Relevanz: Alle fünf Ziegen überstanden die Operation ohne Komplikationen. Die Wunden heilten schnell und nahezu ohne Probleme. Für als Hobbytiere gehaltene Ziegen mit Lactatio falsa, die konservativ nicht therapiert werden können, stellt die Mastektomie eine sinnvolle, erfolgversprechende Behand - lung dar.