Social trauma : psychophysiological correlates and time course of social threat processing in social anxiety disorder

Wabnitz P. Social trauma : psychophysiological correlates and time course of social threat processing in social anxiety disorder. Bielefeld: Bielefeld University; 2013

Micro-combs: a novel generation of optical sources

The quest towards the integration of ultra-fast, high-precision optical clocks is reflected in the large number of high-impact papers on the topic published in the last few years. This interest has been catalysed by the impact that high-precision optical frequency combs (OFCs) have had on metrology and spectroscopy in the last decade [1–5]. OFCs are often referred to as optical rulers: their spectra consist of a precise sequence of discrete and equally-spaced spectral lines that represent precise marks in frequency. Their importance was recognised worldwide with the 2005 Nobel Prize being awarded to T.W. Hänsch and J. Hall for their breakthrough in OFC science [5]. They demonstrated that a coherent OFC source with a large spectrum – covering at least one octave – can be stabilised with a self-referenced approach, where the frequency and the phase do not vary and are completely determined by the source physical parameters. These fully stabilised OFCs solved the challenge of directly measuring optical frequencies and are now exploited as the most accurate time references available, ready to replace the current standard for time. Very recent advancements in the fabrication technology of optical micro-cavities [6] are contributing to the development of OFC sources. These efforts may open up the way to realise ultra-fast and stable optical clocks and pulsed sources with extremely high repetition-rates, in the form of compact and integrated devices. Indeed, the fabrication of high-quality factor (high-Q) micro-resonators, capable of dramatically amplifying the optical field, can be considered a photonics breakthrough that has boosted not only the scientific investigation of OFC sources [7–13] but also of optical sensors and compact light modulators [6,14]

Written threat: electrophysiological evidence for an attention bias to affective words in social anxiety disorder

Wabnitz P, Martens U, Neuner F. Written threat: electrophysiological evidence for an attention bias to affective words in social anxiety disorder. Cognition & Emotion. 2016;30(3):516-538.Social anxiety disorder (SAD) is associated with heightened sensitivity to threat cues, typically represented by emotional facial expressions. To examine if this bias can be transferred to a general hypersensitivity or whether it is specific to disorder relevant cues, we investigated electrophysiological correlates of emotional word processing (alpha activity and event-related potentials) in 20 healthy participants and 20 participants with SAD. The experimental task was a silent reading of neutral, positive, physically threatening and socially threatening words (the latter were abusive swear words) while responding to a randomly presented dot. Subsequently, all participants were asked to recall as many words as possible during an unexpected recall test. Participants with SAD showed blunted sensory processing followed by a rapid processing of emotional words during early stages (early posterior negativity - EPN). At later stages, all participants showed enhanced processing of negative (physically and socially threatening) compared to neutral and positive words (N400). Moreover, at later processing stages alpha activity was increased specifically for negative words in participants with SAD but not in healthy controls. Recall of emotional words for all subjects was best for socially threatening words, followed by negative and positive words irrespective of social anxiety. The present findings indicate that SAD is associated with abnormalities in emotional word processing characterised by early hypervigilance to emotional cues followed by cognitive avoidance at later processing stages. Most importantly, the specificity of these attentional biases seems to change as a function of time with a general emotional bias at early and a more specific bias at later processing stages

Cortical reactions to verbal abuse: event-related brain potentials reflecting the processing of socially threatening words

Wabnitz P, Martens U, Neuner F. Cortical reactions to verbal abuse: event-related brain potentials reflecting the processing of socially threatening words. Neuroreport. 2012;23(13):774-779.Human information processing is sensitive to aversive stimuli, in particular to negative cues that indicate a threat to physical integrity. We investigated the extent to which these findings can be transferred to stimuli that are associated with a social rather than a physical threat. Event-related potentials were recorded during silent reading of neutral, positive, physically threatening, and socially threatening words, whereby socially threatening words were represented by swear words. We found facilitated processing of positive and physically threatening words in contrast to both neutral and socially threatening words at a first potential that emerged at about 120 ms after stimulus onset At a semantic processing stage reflected by the N400, processing of all classes of affective words, including socially threatening words, differed from neutral words. We conclude that socially threatening words as well as neutral words capture more attentional resources than positive and physically threatening words at early stages. However, social threatening words are processed in a manner similar to other emotional words and different from neutral words at higher levels. NeuroReport 23:774-779 (C) 2012 Wolters Kluwer Health vertical bar Lippincott Williams & Wilkins

Dissociation as a Mediator of the Relationship Between Childhood Trauma and Nonsuicidal Self-Injury in Females: A Path Analytic Approach

Franzke I, Wabnitz P, Catani C. Dissociation as a Mediator of the Relationship Between Childhood Trauma and Nonsuicidal Self-Injury in Females: A Path Analytic Approach. Journal of Trauma & Dissociation. 2015;16(3):286-302.New theoretical models of nonsuicidal self-injury (NSSI) postulate that symptoms subsequent to childhood maltreatment rather than childhood maltreatment itself may lead to engagement in NSSI. However, little is known concerning which specific syndromes serve as underlying mechanisms. In this study we sought to examine the mediating effects of dissociative, posttraumatic, and depressive symptoms, 3 often comorbid syndromes following childhood trauma. In addition, we aimed to assess differences between women with and without NSSI. A sample of 87 female inpatients with a history of childhood abuse and neglect was divided into 2 subgroups (NSSI: n = 42, no NSSI: n = 45). The assessment included measures of NSSI characteristics; adverse childhood experiences; and posttraumatic, dissociative, and depressive symptoms. The NSSI group reported significantly more cases of childhood maltreatment and higher levels of current dissociative, posttraumatic, and depressive symptoms than patients without NSSI. The results of a path analysis showed that only dissociation mediated the relationship between a history of child maltreatment and NSSI when all 3 psychopathological variables were included in the model. The findings point toward a strong and rather specific association between dissociative experiences and NSSI and therefore have important implications for clinical practice

This person is saying bad things about you: The influence of physically and socially threatening context information on the processing of inherently neutral faces

Klein F, Iffland B, Schindler S, Wabnitz P, Neuner F. This person is saying bad things about you: The influence of physically and socially threatening context information on the processing of inherently neutral faces. Cognitive, Affective, & Behavioral Neuroscience. 2015;15(4):736-748

Fibre multi-wave mixing combs reveal the broken symmetry of Fermi-Pasta-Ulam recurrence

In optical fibres, weak modulations can grow at the expense of a strong pump to form a triangular comb of sideband pairs, until the process is reversed. Repeated cycles of such conversion and back-conversion constitute a manifestation of the universal nonlinear phenomenon known as Fermi-Pasta-Ulam recurrence. However, it remains a major challenge to observe the coexistence of different types of recurrences owing to the spontaneous symmetry-breaking nature of such a phenomenon. Here, we implement a novel non-destructive technique that allows the evolution in amplitude and phase of frequency modes to be reconstructed via post-processing of the fibre backscattered light. We clearly observe how control of the input modulation seed results in different recursive behaviours emerging from the phase-space structure dictated by the spontaneously broken symmetry. The proposed technique is an important tool to characterize other mixing processes and new regimes of rogue-wave formation and wave turbulence in fibre optics