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Michael Niedeggen

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5 papers
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5

YNICL Journal 2018 Journal Article

Feeling excluded no matter what? Bias in the processing of social participation in borderline personality disorder

  • Anna Weinbrecht
  • Michael Niedeggen
  • Stefan Roepke
  • Babette Renneberg

Background: Patients with Borderline Personality Disorder (BPD) feel ostracized even when they are included. This might be due to a biased processing of social participation in BPD. We examined whether patients with BPD also process social overinclusion in a biased manner, i.e., whether they feel ostracized even when the degree of social participation is increased. Methods: An EEG-compatible version of Cyberball was used to investigate the effects of inclusion and overinclusion (33% vs. 45% ball receipt) on perceived ostracism, need threat and P3 amplitude, an EEG indicator for expectancy violation. Twenty-nine patients with BPD, 28 patients with Social Anxiety Disorder (SAD) and 28 healthy controls (HC) participated. Results: The P3 amplitude was enhanced for patients with BPD and SAD compared to HCs independent of condition. Both patient groups reported more perceived ostracism relative to HCs in the inclusion but not in the overinclusion condition. Only patients with BPD reported stronger need threat in both conditions. Conclusions: The EEG results imply that being socially included violates the expectations of patients with BPD, irrespective of the actual degree of social participation. However, when overincluded, patients with BPD no longer feel ostracized. Except for need threat, patients with SAD might show a comparable bias in the processing of social participation as patients with BPD.

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YNIMG Journal 2007 Journal Article

Timing of V1/V2 and V5+ activations during coherent motion of dots: An MEG study

  • Esther Alonso Prieto
  • Utako B. Barnikol
  • Ernesto Palmero Soler
  • Kevin Dolan
  • Guido Hesselmann
  • Hartmut Mohlberg
  • Katrin Amunts
  • Karl Zilles

In order to study the temporal activation course of visual areas V1 and V5 in response to a motion stimulus, a random dots kinematogram paradigm was applied to eight subjects while magnetic fields were recorded using magnetoencephalography (MEG). Sources generating the registered magnetic fields were localized with Magnetic Field Tomography (MFT). Anatomical identification of cytoarchitectonically defined areas V1/V2 and V5 was achieved by means of probabilistic cytoarchitectonic maps. We found that the areas V1/V2 and V5+ (V5 and other adjacent motion sensitive areas) exhibited two main activations peaks at 100–130 ms and at 140–200 ms after motion onset. The first peak found for V1/V2, which corresponds to the visual evoked field (VEF) M1, always preceded the peak found in V5+. Additionally, the V5+ peak was correlated significantly and positively with the second V1/V2 peak. This result supports the idea that the M1 component is generated not only by the visual area V1/V2 (as it is usually proposed), but also by V5+. It reflects a forward connection between both structures, and a feedback projection to V1/V2, which provokes a second activation in V1/V2 around 200 ms. This second V1/V2 activation (corresponding to motion VEF M2) appeared earlier than the second V5+ activation but both peaked simultaneously. This result supports the hypothesis that both areas also generate the M2 component, which reflects a feedback input from V5+ to V1/V2 and a crosstalk between both structures. Our study indicates that during visual motion analysis, V1/V2 and V5+ are activated repeatedly through forward and feedback connections and both contribute to m-VEFs M1 and M2.

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YNIMG Journal 2006 Journal Article

Pattern reversal visual evoked responses of V1/V2 and V5/MT as revealed by MEG combined with probabilistic cytoarchitectonic maps

  • Utako B. Barnikol
  • Katrin Amunts
  • Jürgen Dammers
  • Hartmut Mohlberg
  • Thomas Fieseler
  • Aleksandar Malikovic
  • Karl Zilles
  • Michael Niedeggen

Pattern reversal stimulation provides an established tool for assessing the integrity of the visual pathway and for studying early visual processing. Numerous magnetoencephalographic (MEG) and electroencephalographic (EEG) studies have revealed a three-phasic waveform of the averaged pattern reversal visual evoked potential/magnetic field, with components N75(m), P100(m), and N145(m). However, the anatomical assignment of these components to distinct cortical generators is still a matter of debate, which has inter alia connected with considerable interindividual variations of the human striate and extrastriate cortex. The anatomical variability can be compensated for by means of probabilistic cytoarchitectonic maps, which are three-dimensional maps obtained by an observer-independent statistical mapping in a sample of ten postmortem brains. Transformed onto a subject's brain under consideration, these maps provide the probability with which a given voxel of the subject's brain belongs to a particular cytoarchitectonic area. We optimize the spatial selectivity of the probability maps for V1 and V2 with a probability threshold which optimizes the self- vs. cross-overlap in the population of postmortem brains used for deriving the probabilistic cytoarchitectonic maps. For the first time, we use probabilistic cytoarchitectonic maps of visual cortical areas in order to anatomically identify active cortical generators underlying pattern reversal visual evoked magnetic fields as revealed by MEG. The generators are determined with magnetic field tomography (MFT), which reconstructs the current source density in each voxel. In all seven subjects, our approach reveals generators in V1/V2 (with a greater overlap with V1) and in V5 unilaterally (right V5 in three subjects, left V5 in four subjects) and consistent time courses of their stimulus-locked activations, with three peak activations in V1/V2 (contributing to C1m/N75m, P100m, and N145m) and two peak activations in V5 (contributing to P100m and N145m). The reverberating V1/V2 and V5 activations demonstrate the effect of recurrent activation mechanisms including V1 and extrastriate areas and/or corticofugal feedback loops. Our results demonstrate that the combined investigation of MEG signals with MFT and probabilistic cytoarchitectonic maps significantly improves the anatomical identification of active brain areas.

Details DOI
v2026.09.13