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

Subacute alpha frequency (10Hz) subthalamic stimulation for emotional processing in Parkinson's disease

BACKGROUND

Psychiatric comorbidities are common in Parkinson's disease (PD) and may change with high-frequency stimulation targeting the subthalamic nucleus. Numerous accounts indicate subthalamic alpha-frequency oscillation is implicated in emotional processing. While intermittent alpha-frequency (10Hz) stimulation induces positive emotional effects, with more ventromedial contacts inducing larger effects, little is known about the subacute effect of ventral 10Hz subthalamic stimulation on emotional processing.

OBJECTIVE/HYPOTHESIS

To evaluate the subacute effect of 10Hz stimulation at bilateral ventral subthalamic nucleus on emotional processing in PD patients using an affective task, compared to that of clinical-frequency stimulation and off-stimulation.

METHODS

Twenty PD patients with bilateral subthalamic deep brain stimulation for more than six months were tested with the affective task under three stimulation conditions (10Hz, 130Hz, and off-stimulation) in a double-blinded randomized design.

RESULTS

While 130Hz stimulation reduced arousal ratings in all patients, 10Hz stimulation increased arousal selectively in patients with higher depression scores. Furthermore, 10Hz stimulation induced a positive shift in valence rating to negative emotional stimuli in patients with lower apathy scores, and 130Hz stimulation led to more positive valence to emotional stimuli in the patients with higher apathy scores. Notably, we found correlational relationships between stimulation site and affective rating: arousal ratings increase with stimulation from anterior to posterior site, and positive valence ratings increase with stimulation from dorsal to ventral site of the ventral subthalamic nucleus.

CONCLUSIONS

Our findings highlight the distinctive role of 10Hz stimulation on subjective emotional experience and unveil the spatial organization of the stimulation effect.

[Belief updating and mood congruence in depressive disorder]

Depressive disorder is characterized by a polymorphic symptomatology associating emotional, cognitive and behavioral disturbances. One of the most specific symptoms is negative beliefs, called congruent to mood. Despite the importance of these beliefs in the development, the maintenance, and the recurrence of depressive episodes, little is known about the processes underlying the generation of depressive beliefs. In this paper, we detail the link between belief updating mechanisms and the genesis of depressive beliefs. We show how depression alters information processing, generating cognitive immunization when processing positive information, affective updating bias related to the valence of belief and prediction error, and difficultie to disengage from negative information. We suggest that disruption of belief-updating mechanisms forms the basis of belief-mood congruence in depression.

Serotonergic influence on depressive symptoms and trait anxiety is mediated by negative life events and frontal activation in children and adolescents

Depression and anxiety are common in childhood and adolescence. Even though cardinal symptoms differ, there is a considerable overlap regarding the pathogenic influence of serotonergic innervation, negative life experience, disturbed emotion perception/affect regulation, and impaired neural functioning in the fronto-limbic circuit. In this study, we examined the effect of the 5-HTTLPR/rs25531 genotype on depressive symptoms and trait anxiety under the consideration of the amount of negative life events in healthy children and adolescents (N = 389). In a subsample of 49 subjects, we performed fMRI to add fronto-limbic brain activation as a second interacting factor. Across all subjects, negative life events moderated the influence of the 5-HTTLPR/rs25531 genotype on both depressive symptoms and trait anxiety. In the fMRI subsample, 5-HTTLPR/rs25531 S + S/L_G + S/L_A + L_GL_A + L_GL_G genotype-associated left middle frontal gyrus (MFG) activation mediated the influence of 5-HTTLPR/rs25531 genotype on depressive symptoms, however, only in combination with negative life events. Genetic influence on trait anxiety was predominantly mediated by negative life events; only L_AL_A genotype-specific activation in the right MFG worked as a mediator in combination with negative life events. The present findings hint towards distinct mechanisms mediating the influence of 5-HTTLPR/rs25531 genotype on depressive symptoms and anxiety, with negative life events playing a crucial role in both phenotypes. With regard to depressive symptoms, however, this influence was only visible in combination with MFG activation, whereas, in anxiety, it was independent of brain activation.

Effect of CBT on Biased Semantic Network in Panic Disorder: A Multicenter fMRI Study Using Semantic Priming

OBJECTIVE

Cognitive-behavioral therapy (CBT) has been hypothesized to act by reducing the pathologically enhanced semantic, anxiety-related associations of patients with panic disorder. This study investigated the effects of CBT on the behavioral and neural correlates of the panic-related semantic network in patients with panic disorder.

METHODS

An automatic semantic priming paradigm specifically tailored for panic disorder, in which panic symptoms (e.g., "dizziness") were primed by panic triggers (e.g., "elevator") compared with neutral words (e.g., "bottle"), was performed during functional MRI scanning with 118 patients with panic disorder (compared with 150 healthy control subjects) before and 42 patients (compared with 52 healthy control subjects) after an exposure-based CBT. Neural correlates were investigated by comparing 103 pairs of matched patients and control subjects at the baseline (for patients) or T1 (for control subjects) assessment and 39 pairs at the posttreatment or T2 assessment.

RESULTS

At baseline or T1, patients rated panic-trigger/panic-symptom word pairs with higher relatedness and higher negative valence compared with healthy control subjects. Patients made faster lexical decisions to the panic-symptom words when they were preceded by panic-trigger words. This panic-priming effect in patients (compared with control subjects) was reflected in suppressed neural activation in the left and right temporal cortices and insulae and enhanced activation in the posterior and anterior cingulate cortices. After CBT, significant clinical improvements in the patient group were observed along with a reduction in relatedness and negative valence rating and attenuation of neural activation in the anterior cingulate cortex for processing of panic-trigger/panic-symptom word pairs.

CONCLUSIONS

The findings support a biased semantic network in panic disorder, which is normalized after CBT. Attenuation of anterior cingulate cortex activation for processing of panic-related associations provides a potential mechanism for future therapeutic interventions.

Aberrant attentive and inattentive brain activity to auditory negative words, and its relation to persecutory delusion in patients with schizophrenia

BACKGROUND AND PURPOSE

Previous research has suggested that deficits in emotion recognition are involved in the pathogenesis of persecutory delusion in schizophrenia. Although disruption in auditory and language processing is crucial in the pathophysiology of schizophrenia, the neural basis for the deficits in emotion recognition of auditorily presented language stimuli and its relation to persecutory delusion have not yet been clarified.

PATIENTS AND METHODS

The current functional magnetic resonance imaging study used a dichotic listening task for 15 patients with schizophrenia and 23 healthy controls matched for age, sex, parental socioeconomic background, handedness, dexterous ear, and intelligence quotient. The participants completed a word recognition task on the attended side in which a word with emotionally valenced content (negative/neutral) was presented to one ear and a different neutral word was presented to the other ear. Participants selectively attended to either ear.

RESULTS

The whole brain analysis detected the aberrant neural activity in the right inferior frontal gyrus in the patients with schizophrenia compared to that in the controls (P<0.05, false discovery rate-corrected). Brain activity in the right pars triangularis of the inferior frontal gyrus was significantly reduced when negatively valenced words were presented to the right ear, whereas the activity of the same region was significantly enhanced when these words were presented to the left ear, irrespective of the attended ear, in the participants with schizophrenia compared to the controls. Furthermore, this diminished brain response to auditorily presented negatively valenced words significantly correlated with severe positive symptoms (r=-0.67, P=0.006) and delusional behavior (r=-0.62, P=0.014) in the patients with schizophrenia.

CONCLUSION

The present results indicate that the significantly impaired brain activity in response to auditorily presented negatively valenced words in the right pars triangularis of the inferior frontal gyrus is associated with the pathogenesis of positive symptoms such as persecutory delusion.

The Mnemonic Effects of Novelty and Appropriateness in Creative Chunk Decomposition Tasks

Creativeness has been widely recognized as the ability to generate thoughts that are both novel (new) and appropriate (useful) (Barron, 1955). In this paper, we investigated the mnemonic effects of novelty and appropriateness in chunk decomposition tasks. Studies 1 and 2 utilized classical recognition tasks (explicit memory) and ambiguous word identification tasks (implicit memory) to reveal whether novelty and appropriateness are involved in different mnemonic systems. A 2 (familiarity) × 2 (appropriateness) experimental design was utilized in our experiments, and the four conditions were familiar-appropriate, familiar-inappropriate, novel-appropriate and novel-inappropriate. The results indicated that insight induced by novelty (novel-appropriate condition) has a better performance than other conditions; and further, found an interesting phenomenon of Zeigarnik-like effect which referred to remembering uncompleted tasks better than completed tasks (Zeigarnik, 1927). We further conducted Study 3 to ask participants to recall the encoding process (how the characters had been decomposed in the learning stage), which was more sensitive to Zeigarnik effect and indicated that performance of familiar-appropriate condition (uncompleted tasks) was better than other conditions.

Neural correlates of processing emotional prosody in unipolar depression

Major depressive disorder (MDD) is characterized by a biased emotion perception. In the auditory domain, MDD patients have been shown to exhibit attenuated processing of positive emotions expressed by speech melody (prosody). So far, no neuroimaging studies examining the neural basis of altered processing of emotional prosody in MDD are available. In this study, we addressed this issue by examining the emotion bias in MDD during evaluation of happy, neutral, and angry prosodic stimuli on a five-point Likert scale during functional magnetic resonance imaging (fMRI). As expected, MDD patients rated happy prosody less intense than healthy controls (HC). At neural level, stronger activation in the middle superior temporal gyrus (STG) and the amygdala was found in all participants when processing emotional as compared to neutral prosody. MDD patients exhibited an increased activation of the amygdala during processing prosody irrespective of valence while no significant differences between groups were found for the STG, indicating that altered processing of prosodic emotions in MDD occurs rather within the amygdala than in auditory areas. Concurring with the valence-specific behavioral effect of attenuated evaluation of positive prosodic stimuli, activation within the left amygdala of MDD patients correlated with ratings of happy, but not neutral or angry prosody. Our study provides first insights in the neural basis of reduced experience of positive information and an abnormally increased amygdala activity during prosody processing.

The functional and structural characteristics of the emotion network in alexithymia

BACKGROUND

Alexithymia is a multifaceted personality trait characterized by emotional dysfunction.

METHODS

In this study, the functional and structural features of the emotion network in alexithymia were investigated using resting-state functional MRI (rsfMRI), voxel-based morphometry (VBM), functional connectivity (FC) analysis, and diffusion tensor imaging (DTI). Alexithymic and non-alexithymic students were recruited from the local university. The intrinsic neural activity and gray matter density of the brain regions in the emotion network were measured using rsfMRI and VBM; the FC and structural connectivity of the brain regions in the emotion network were measured using FC analysis and DTI.

RESULTS

The altered intrinsic neural activity in V1, rostral dorsal anterior cingulate cortex, and left amygdala, and the weak FC between V1 and left superior temporal gyrus and V1 and left paracentral lobule in alexithymia subjects were identified. However, no alteration of the structure and structural connectivity of the emotion network was identified.

CONCLUSION

The results indicated that the development of alexithymia might have been caused only by slight alteration of the neural activity. Furthermore, the results suggest that noninvasive treatment technologies for improving the brain activity are suitable for alexithymic individuals.

Neural correlates of individual differences in anxiety sensitivity: an fMRI study using semantic priming

Individuals with high anxiety sensitivity (AS) have an increased risk of developing anxiety disorders and are more biased in how they process fear-related stimuli. This study investigates the neural correlates of fear-related words and word associations in high- and low-AS individuals. We used a semantic priming paradigm during functional magnetic resonance imaging in which three types of target words (fear symptoms, e.g. 'dizziness'; neutral, e.g. 'drink'; and pseudowords, e.g. 'salkom') were preceded by two types of prime words (fear-triggers, e.g. 'elevator'; and neutral, e.g. 'bottle'). Subjects with high AS rated fear-symptom words (vs neutral words) as more unpleasant than low-AS individuals; they also related these words more strongly to fear-triggers and showed prolonged reaction times. During the processing of fear-symptom words, greater activation in the left anterior insula was observed in high-AS subjects than in low-AS subjects. Lower activation in the left inferior frontal gyrus, angular gyrus, fusiform gyrus and bilateral amygdalae was found in high-AS subjects when fear-symptom words were preceded by fear-trigger words. The findings suggest that cognitive biases and the anterior insula play a crucial role in high-AS individuals. Furthermore, semantic processes may contribute to high AS and the risk of developing anxiety disorders.

Effects of empathic social responses on the emotions of the recipient

Empathy is highly relevant for social behavior and can be verbally expressed by voicing sympathy and concern (emotional empathy) as well as by paraphrasing or stating that one can mentally reconstruct and understand another person's thoughts and feelings (cognitive empathy). In this study, we investigated the emotional effects and neural correlates of receiving empathic social responses after negative performance feedback and compared the effects of emotionally vs. cognitively empathic comments. 20 participants (10 male) underwent functional magnetic resonance imaging while receiving negative performance feedback for a cognitive task. Performance feedback was followed by verbal comments either expressing cognitive and emotional empathy or demonstrating a lack of empathy. Empathic comments in general led to less negative self-reported feelings and calmer breathing. At the neural level, empathic comments induced activity in regions associated with social cognition and emotion processing, specifically in right postcentral gyrus and left cerebellum (cognitively empathic comments), right precentral gyrus, the opercular part of left inferior frontal gyrus, and left middle temporal gyrus (emotionally empathic comments), as well as the orbital part of the left middle frontal gyrus and left superior parietal gyrus (emotionally empathic vs. unempathic comments). The study shows that cognitively and emotionally empathic comments appear to be processed in partially separable neural systems. Furthermore, confirming and expanding on another study on the same subject, the present results demonstrate that the social display of cognitive empathy exerts almost as positive effects on the recipient's feelings and emotions in states of distress as emotionally empathic response does. This can be relevant for professional settings in which strong negative emotions need to be de-escalated while maintaining professional impartiality, which may allow the display of cognitive but not emotional empathy.

Influence of Priming on Patient-Reported Outcome Measures: A Randomized Controlled Trial

BACKGROUND

Patient-reported outcome measures (PROMs) are influenced by psychosocial factors, but it is unknown whether we can influence PROM scores by modifying the mindset of the patient.

PURPOSE

We assessed whether priming affects scores on PROMs.

METHODS

In all, 168 patients with musculoskeletal illness participated in this double-blinded, randomized, controlled, parallel study between July 2014 and October 2014 in a level I trauma center. Inclusion criteria were patients aged 18 years or older with English fluency and literacy and the ability to provide informed consent. Priming was performed by means of the Pain Catastrophizing Scale (PCS). The patients were randomized (1:1:1) into 3 groups: intervention group I was negatively primed with the original PCS; intervention group II was positively primed with a positively phrased PCS group; and control group III was not primed. Assessments were performed using PROMs on the domain of physical function, depression, and pain. Bivariate and multivariable regression analyses were conducted.

RESULTS

The intervention and control groups were well balanced in demographic and condition-specific characteristics. The positive PCS was independently associated with higher PROM scores in the physical function domain (Patient-Reported Outcome Measurement Information System Upper Extremity Function: coefficient = 4.7, partial R(2) = 0.042; CI: 1.2-8.2; p < 0.010).

CONCLUSIONS

Patients primed with a positively phrased version of the PCS reported less functional disability as compared with patients who were either negatively primed or not primed at all. This suggests that by influencing the mindset, PROMs can be influenced, resulting in better outcome if positively primed.

LEVEL OF EVIDENCE

Level 1 therapeutic study.

TRIAL REGISTRATION

NCT02209259.

Influence of depressive symptoms on memory in transient global amnesia

INTRODUCTION

Recent studies have shown that patients with transient global amnesia (TGA) experience a depressive mood during the episode. However, little evidence has been found of possible mood congruency effects on memory, which are probably masked by the massive anterograde amnesia. An implicit assessment could provide a means of settling this question.

METHODS

First, we measured patients' emotional states on psychopathological scales. Second, we administered a lexical decision task to assess three priming effects: Semantic priming (SP; table-chair), emotional priming (EP; murder-garbage), and emotional plus semantic priming (ESP; cemetery-coffin).

RESULTS

Patients displayed a more depressed mood than controls. For patients, we found a SP effect in the ESP condition and a striking inhibition effect (i.e., negative target recognized more slowly when preceded by a negative prime rather than a neutral one) in the EP condition. For controls, a priming effect was found in the SP and ESP conditions, but not the EP condition. Finally, whereas the priming effect was greater in SP than in the other two conditions for controls, for patients it was the EP condition that stood out from the other two, being the only condition that led to an inhibition effect.

CONCLUSIONS

We highlighted a mood congruency effect in TGA which could impel patients to focus their attention on negative information. While the negative valence of items always led to a slowdown in reaction times for both patients and controls, attesting to a negativity bias, this bias was greater in patients, leading to an inhibition effect.

An fMRI-study on semantic priming of panic-related information in depression without comorbid anxiety

Depression often involves anxiety symptoms and shows a strong comorbidity with panic disorder. However, the neural basis is unclear. The aim of the current study was to use semantic priming to investigate the neural correlates of panic and anxiety-related information processing in depression. In a lexical decision task, panic/agoraphobia-disorder-related and neutral word-pairs were presented during functional magnetic resonance imaging. Participants comprised 19 patients with major depression but without comorbid anxiety and 19 demographically matched controls. On a behavioral level, comparable significant priming effects were found for the neutral condition, while only patients showed a significant inhibition effect (slower reaction time for panic-related stimuli) for the panic condition. On a neural level, significant group differences emerged in left fronto-parietal (enhanced activation for patients) and left temporo-occipital regions (reduced activation for patients). The results showed that depressed patients recruit not only areas related to the interaction of emotion and semantic processing but also regions that are related to fear circuitry to process panic-related information. Hence, in the context of depression, there seems to be a pathological processing of panic-related information that could play an important role during the disorder and should be considered.

Aberrant interference of auditory negative words on attention in patients with schizophrenia

Previous research suggests that deficits in attention-emotion interaction are implicated in schizophrenia symptoms. Although disruption in auditory processing is crucial in the pathophysiology of schizophrenia, deficits in interaction between emotional processing of auditorily presented language stimuli and auditory attention have not yet been clarified. To address this issue, the current study used a dichotic listening task to examine 22 patients with schizophrenia and 24 age-, sex-, parental socioeconomic background-, handedness-, dexterous ear-, and intelligence quotient-matched healthy controls. The participants completed a word recognition task on the attended side in which a word with emotionally valenced content (negative/positive/neutral) was presented to one ear and a different neutral word was presented to the other ear. Participants selectively attended to either ear. In the control subjects, presentation of negative but not positive word stimuli provoked a significantly prolonged reaction time compared with presentation of neutral word stimuli. This interference effect for negative words existed whether or not subjects directed attention to the negative words. This interference effect was significantly smaller in the patients with schizophrenia than in the healthy controls. Furthermore, the smaller interference effect was significantly correlated with severe positive symptoms and delusional behavior in the patients with schizophrenia. The present findings suggest that aberrant interaction between semantic processing of negative emotional content and auditory attention plays a role in production of positive symptoms in schizophrenia. (224 words).

Emotional verbal fluency: a new task on emotion and executive function interaction

The present study introduces "Emotional Verbal Fluency" as a novel (partially computerized) task, which is aimed to investigate the interaction between emotionally loaded words and executive functions. Verbal fluency tasks are thought to measure executive functions but the interaction with emotional aspects is hardly investigated. In the current study, a group of healthy subjects (n = 21, mean age 25 years, 76% females) were asked to generate items that are either part of a semantic category (e.g., plants, toys, vehicles; standard semantic verbal fluency) or can trigger the emotions joy, anger, sadness, fear and disgust. The results of the task revealed no differences between performance on semantic and emotional categories, suggesting a comparable task difficulty for healthy subjects. Hence, these first results on the comparison between semantic and emotional verbal fluency seem to highlight that both might be suitable for examining executive functioning. However, an interaction was found between the category type and repetition (first vs. second sequence of the same category) with larger performance decrease for semantic in comparison to emotional categories. Best performance overall was found for the emotional category "joy" suggesting a positivity bias in healthy subjects. To conclude, emotional verbal fluency is a promising approach to investigate emotional components in an executive task, which may stimulate further research, especially in psychiatric patients who suffer from emotional as well as cognitive deficits.

Whole-brain functional connectivity identification of functional dyspepsia

Recent neuroimaging studies have shown local brain aberrations in functional dyspepsia (FD) patients, yet little attention has been paid to the whole-brain resting-state functional network abnormalities. The purpose of this study was to investigate whether FD disrupts the patterns of whole-brain networks and the abnormal functional connectivity could reflect the severity of the disease. The dysfunctional interactions between brain regions at rest were investigated in FD patients as compared with 40 age- and gender- matched healthy controls. Multivariate pattern analysis was used to evaluate the discriminative power of our results for classifying patients from controls. In our findings, the abnormal brain functional connections were mainly situated within or across the limbic/paralimbic system, the prefrontal cortex, the tempo-parietal areas and the visual cortex. About 96% of the subjects among the original dataset were correctly classified by a leave one-out cross-validation approach, and 88% accuracy was also validated in a replication dataset. The classification features were significantly associated with the patients' dyspepsia symptoms, the self-rating depression scale and self-rating anxiety scale, but it was not correlated with duration of FD patients (p>0.05). Our results may indicate the effectiveness of the altered brain functional connections reflecting the disease pathophysiology underling FD. These dysfunctional connections may be the epiphenomena or causative agents of FD, which may be affected by clinical severity and its related emotional dimension of the disease rather than the clinical course.