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The core feature of separation anxiety is excessive distress when faced with actual or perceived separation from people to whom the individual has a strong emotional attachment. So far little is known about the neurobiological underpinnings of separation anxiety. Therefore, we investigated functional (amygdala responsiveness and functional connectivity during threat-related emotion processing) and structural (grey matter volume) imaging markers associated with separation anxiety as measured with the Relationship Scale Questionnaire in a large sample of healthy adults from the Münster Neuroimaging Cohort (N = 320). We used a robust emotional face-matching task and acquired high-resolution structural images for morphometric analyses using voxel-based morphometry. The main results were positive associations of separation anxiety scores with amygdala reactivity to emotional faces as well as increased amygdala grey matter volumes. A functional connectivity analysis revealed positive associations between separation anxiety and functional coupling of the amygdala with areas involved in visual processes and attention, including several occipital and somatosensory areas. Taken together, the results suggest a higher emotional involvement in subjects with separation anxiety while watching negative facial expressions, and potentially secondary neuro-structural adaptive processes. These results could help to understand and treat (adult) separation anxiety. [ABSTRACT FROM AUTHOR]

Background Bipolar disorder and Major depressive disorder are difficult to differentiate during depressive episodes, motivating research for differentiating neurobiological markers. Dysfunctional amygdala responsiveness during emotion processing has been implicated in both disorders, but the important rapid and automatic stages of emotion processing in the amygdala have so far never been investigated in bipolar patients. Methods fMRI data of 22 bipolar depressed patients (BD), 22 matched unipolar depressed patients (MDD), and 22 healthy controls (HC) were obtained during processing of subliminal sad, happy and neutral faces. Amygdala responsiveness was investigated using standard univariate analyses as well as pattern-recognition techniques to differentiate the two clinical groups. Furthermore, medication effects on amygdala responsiveness were explored. Results All subjects were unaware of the emotional faces. Univariate analysis revealed a significant group × emotion interaction within the left amygdala. Amygdala responsiveness to sad>neutral faces was increased in MDD relative to BD. In contrast, responsiveness to happy>neutral faces showed the opposite pattern, with higher amygdala activity in BD than in MDD. Most of the activation patterns in both clinical groups differed significantly from activation patterns of HC-and therefore represent abnormalities. Furthermore, pattern classification on amygdala activation to sad>happy faces yielded almost 80% accuracy differentiating MDD and BD patients. Medication had no significant effect on these findings. Conclusions Distinct amygdala excitability during automatic stages of the processing of emotional faces may reflect differential pathophysiological processes in BD versus MDD depression, potentially representing diagnosis-specific neural markers mostly unaffected by current psychotropic medication. Hum Brain Mapp 35:2995-3007, 2014. © 2013 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

Background: Altered memory processes are thought to be a key mechanism in the etiology of anxiety disorders, but little is known about the neural correlates of fear learning and memory biases in patients with social phobia. The present study therefore examined whether patients with social phobia exhibit different patterns of neural activation when confronted with recently acquired emotional stimuli. Methods: Patients with social phobia and a group of healthy controls learned to associate pseudonames with pictures of persons displaying either a fearful or a neutral expression. The next day, participants read the pseudonames in the magnetic resonance imaging scanner. Afterwards, 2 memory tests were carried out. Results: We enrolled 21 patients and 21 controls in our study. There were no group differences for learning performance, and results of the memory tests were mixed. On a neural level, patients showed weaker amygdala activation than controls for the contrast of names previously associated with fearful versus neutral faces. Social phobia severity was negatively related to amygdala activation. Moreover, a detailed psychophysiological interaction analysis revealed an inverse correlation between disorder severity and frontolimbic connectivity for the emotional > neutral pseudonames contrast. Limitations: Our sample included only women. Conclusion: Our results support the theory of a disturbed cortico limbic interplay, even for recently learned emotional stimuli. We discuss the findings with regard to the vigilance-avoidance theory and contrast them to results indicating an oversensitive limbic system in patients with social phobia. [ABSTRACT FROM AUTHOR]

Emotional words-as symbols for biologically relevant concepts-are preferentially processed in brain regions including the visual cortex, frontal and parietal regions, and a corticolimbic circuit including the amygdala. Some of the brain structures found in functional magnetic resonance imaging are not readily apparent in electro- and magnetoencephalographic (EEG; MEG) measures. By means of a combined EEG/MEG source localization procedure to fully exploit the available information, we sought to reduce these discrepancies and gain a better understanding of spatiotemporal brain dynamics underlying emotional-word processing. Eighteen participants read high-arousing positive and negative, and low-arousing neutral nouns, while EEG and MEG were recorded simultaneously. Combined current-density reconstructions (L2-minimum norm least squares) for two early emotion-sensitive time intervals, the P1 (80-120 ms) and the early posterior negativity (EPN, 200-300 ms), were computed using realistic individual head models with a cortical constraint. The P1 time window uncovered an emotion effect peaking in the left middle temporal gyrus. In the EPN time window, processing of emotional words was associated with enhanced activity encompassing parietal and occipital areas, and posterior limbic structures. We suggest that lexical access, being underway within 100 ms, is speeded and/or favored for emotional words, possibly on the basis of an 'emotional tagging' of the word form during acquisition. This gives rise to their differential processing in the EPN time window. The EPN, as an index of natural selective attention, appears to reflect an elaborate interplay of distributed structures, related to cognitive functions, such as memory, attention, and evaluation of emotional stimuli. Hum Brain Mapp 35:875-888, 2014. © 2012 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

Major depression has been repeatedly associated with amygdala hyper-responsiveness to negative (but not positive) facial expressions at early, automatic stages of emotion processing using subliminally presented stimuli. However, it is not clear whether this 'limbic bias' is a correlate of depression or represents a vulnerability marker preceding the onset of the disease. Because childhood maltreatment is a potent risk factor for the development of major depression in later life, we explored whether childhood maltreatment is associated with amygdalar emotion processing bias in maltreated but healthy subjects. Amygdala responsiveness to subliminally presented sad and happy faces was measured by means of fMRI at 3 T in N = 150 healthy subjects carefully screened for psychiatric disorders. Childhood maltreatment was assessed by the 25-item childhood trauma questionnaire (CTQ). A strong association of CTQ-scores with amygdala responsiveness to sad, but not happy facial expressions emerged. This result was further qualified by an interaction of emotional valence and CTQ-scores and was not confounded by trait anxiety, current depression level, age, gender, intelligence, education level, and more recent stressful life-events. Childhood maltreatment is apparently associated with detectable changes in amygdala function during early stages of emotion processing which resemble findings described in major depression. Limbic hyper-responsiveness to negative facial cues could be a consequence of the experience of maltreatment during childhood increasing the risk of depression in later life. Limitation: the present association of limbic bias and maltreatment was demonstrated in the absence of psychopathological abnormalities, thereby limiting strong conclusions. Hum Brain Mapp 34:2899-2909, 2013. © 2012 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

Background: Anhedonia has long been recognized as a key feature of major depressive disorders, but little is known about the association between hedonic symptoms and neurobiological processes in depressed patients. We investigated whether amygdala mood congruent responses to emotional stimuli in depressed patients are correlated with anhedonic symptoms at automatic levels of processing. Methods: We measured amygdala responsiveness to subliminally presented sad and happy facial expressions in depressed patients and matched healthy controls using functional magnetic resonance imaging. Amygdala responsiveness was compared between patients and healthy controls within a 2 (group) × 2 (emotion) design. In addition, we correlated patients' amygdala responsiveness to sad and happy facial stimuli with self-report questionnaire measures of anhedonia. Results: We included 35 patients and 35 controls in our study. As in previous studies, we observed a strong emotion × group interaction in the bilateral amygdala: depressed patients showed greater amygdala responses to sad than happy faces, whereas healthy controls responded more strongly to happy than sad faces. The lack of automatic right amygdala responsiveness to happy faces in depressed patients was associated with higher physical anhedonia scores. Limitations: Almost all depressed patients were taking antidepressant medications. Conclusion: We replicated our previous finding of depressed patients showing automatic amygdala mood-congruent biases in terms of enhanced reactivity to negative emotional stimuli and reduced activity to positive emotional stimuli. The altered amygdala processing of positive stimuli in patients was associated with anhedonia scores. The results indicate that reduced amygdala responsiveness to positive stimuli may contribute to anhedonic symptoms due to reduced/inappropriate salience attribution to positive information at very early processing levels. [ABSTRACT FROM AUTHOR]

We report two picture-word interference experiments investigating conceptual and lexical activation, and response selection, in speaking. We varied stimulus onset asynchrony to investigate potential fine-grained activation and competition effects. Morphologically related existing and pseudoword adjectives, as well as associatively related adjectives, served as context stimuli in Experiment 1. In Experiment 2, we focused on semantic interference by using morphologically related and unrelated subordinates of the target concept as context stimuli. Morphologically complex pseudowords were also included as context stimuli. Pseudowords should not interfere, given that they have no lexical or conceptual representation. We consistently obtained facilitation with all morphologically related context stimuli, irrespective of their lexical status. We argue that effects originate at the word-form level, and discuss how our results may help decide among the many explanations of semantic interference in picture naming. [ABSTRACT FROM AUTHOR]

Processing non-adjacent dependencies is considered to be one of the hallmarks of human language. Assuming that sequence-learning tasks provide a useful way to tap natural-language-processing mechanisms, we cross-modally combined serial reaction time and artificial-grammar learning paradigms to investigate the processing of multiple nested (A1A2A3B3B2B1) and crossed dependencies (A1A2A3B1B2B3), containing either three or two dependencies. Both reaction times and prediction errors highlighted problems with processing the middle dependency in nested structures (A1A2A3B3_B1), reminiscent of the 'missing-verb effect' observed in English and French, but not with crossed structures (A1A2A3B1_B3). Prior linguistic experience did not play a major role: native speakers of German and Dutch-which permit nested and crossed dependencies, respectively- showed a similar pattern of results for sequences with three dependencies. As for sequences with two dependencies, reaction times and prediction errors were similar for both nested and crossed dependencies. The results suggest that constraints on the processing of multiple non-adjacent dependencies are determined by the specific ordering of the non-adjacent dependencies (i.e. nested or crossed), as well as the number of non-adjacent dependencies to be resolved (i.e. two or three). Furthermore, these constraints may not be specific to language but instead derive from limitations on structured sequence learning. [ABSTRACT FROM AUTHOR]

The present ERP study investigated individual differences in the integration of verbal descriptions and visual object representations. Participants saw pictures of objects (e.g., a swimming duck) after listening to noun phrases describing the same object in the identical state, a shape-mismatching state ('flying duck'), or an incongruent object (e.g., 'sliced bread'). Individual differences in the vividness of mental imagery and preference for mental imagery were assessed after the experiment. ERP effects of context arose 170 ms after picture onset, differentiating the incongruent-object context from the other two. The N400 mirrored these context effects. Self-rated vividness of imagery affected responses to pictures already after 100 ms, and modulated the N400 effect. Participants with highly vivid imagery showed larger context effects than participants low in imagery. The context effects at 170 ms were not modulated by individual differences. [ABSTRACT FROM AUTHOR]

We investigated the impact of derived German verbs on the production and recognition of morphologically related simple verbs. In order to disentangle effects of morphological, semantic, and phonological relatedness, target verbs were combined (e.g., zählen - to count) with four context verbs: Two morphologically related context verbs that were either semantically transparent (verzählen - to miscount) or semantically opaque (erzählen - to tell), a semantically related (rechnen - to calculate) and a phonologically related (zähmen - to tame) context verb. Morphologically related complex verbs reduced picture naming latencies as well as lexical decision latencies. Semantically related verbs did not show any reliable effects. In production, morphological facilitation was almost four times larger than phonological facilitation. In comprehension, pure form overlap produced inhibition. We argue that in German, production and comprehension processes operate on morphologically decomposed lexical form representations. Independent from semantic transparency, complex verbs are broken down into their morphemes during comprehension and are assembled during production. [ABSTRACT FROM AUTHOR]