@article{WendtLoewWeymaretal.2017,
  author    = {Wendt, Julia and Loew, Andreas and Weymar, Mathias and Lotze, Martin and Hamm, Alfons O.},
  title     = {Active avoidance and attentive freezing in the face of approaching threat},
  series = {NeuroImage : a journal of brain function},
  volume    = {158},
  journal   = {NeuroImage : a journal of brain function},
  publisher = {Elsevier},
  address   = {San Diego},
  issn      = {1053-8119},
  doi       = {10.1016/j.neuroimage.2017.06.054},
  pages     = {196 -- 204},
  year      = {2017},
  abstract  = {Defensive behaviors in animals and humans vary dynamically with increasing proximity of a threat and depending upon the behavioral repertoire at hand. The current study investigated physiological and behavioral adjustments and associated brain activation when participants were exposed to dynamically approaching threat that was either inevitable or could be avoided by motor action. When the approaching threat was inevitable, attentive freezing was observed as indicated by fear bradycardia, startle potentiation, and a dynamic increase in activation of the anterior insula and the periaqueductal grey. In preparation for active avoidance a switch in defensive behavior was observed characterized by startle inhibition and heart rate acceleration along with potentiated activation of the amygdala and the periaqueductal grey. Importantly, the modulation of defensive behavior according to threat imminence and the behavioral option at hand was associated with activity changes in the ventromedial prefrontal cortex. These findings improve our understanding of brain mechanisms guiding human behavior during approaching threat depending on available resources.},
  language  = {en}
}
@article{WirknerVenturaBortSchwabeetal.2019,
  author    = {Wirkner, Janine and Ventura-Bort, Carlos and Schwabe, Lars and Hamm, Alfons O. and Weymar, Mathias},
  title     = {Chronic stress and emotion: Differential effects on attentional processing and recognition memory},
  series = {Psychoneuroendocrinology},
  volume    = {107},
  journal   = {Psychoneuroendocrinology},
  publisher = {Elsevier},
  address   = {Oxford},
  issn      = {0306-4530},
  doi       = {10.1016/j.psyneuen.2019.05.008},
  pages     = {93 -- 97},
  year      = {2019},
  abstract  = {Previous research indicates that acute stress around the time of learning facilitates attention and memory for emotionally salient information. Despite accumulating evidence for these acute stress effects, less is known about the role of chronic stress. In the present study, we therefore tested emotional and neutral scene processing and later recognition memory in female participants using hair cortisol concentrations as a biological marker for chronic stress. Event-related potentials recorded during picture viewing indicated enhanced late positive potentials (LPPs) for emotional, relative to neutral contents. These brain potentials varied as a function of long-term hair cortisol levels: hair-cortisol levels were positively related to overall LPP amplitudes. Results from recognition memory testing one week after encoding revealed better memory for emotional relative to neutral scenes. Hair-cortisol levels, however, were related to poorer memory accuracy. Taken together, our results indicate that chronic stress enhanced attentional processing during encoding of new stimuli and impaired later recognition memory. Results are discussed with regard to putatively opposite effects of chronic stress on certain brain regions (e.g., amygdala and hippocampus).},
  language  = {en}
}
@article{WirknerWeymarLoewetal.2017,
  author    = {Wirkner, Janine and Weymar, Mathias and Loew, Andreas and Hamm, Carmen and Struck, Anne-Marie and Kirschbaum, Clemens and Hamm, Alfons O.},
  title     = {Cognitive functioning and emotion processing in breast cancer survivors and controls: An ERP pilot study},
  series = {Psychophysiology : journal of the Society for Psychophysiological Research},
  volume    = {54},
  journal   = {Psychophysiology : journal of the Society for Psychophysiological Research},
  publisher = {Wiley},
  address   = {Hoboken},
  issn      = {0048-5772},
  doi       = {10.1111/psyp.12874},
  pages     = {1209 -- 1222},
  year      = {2017},
  abstract  = {Diagnosis and treatment of breast cancer is a very emotionally aversive and stressful life event, which can lead to impaired cognitive functioning and mental health. Breast cancer survivors responding with repressive emotion regulation strategies often show less adaptive coping and adverse outcomes. We investigated cognitive functioning and neural correlates of emotion processing using ERPs. Self-report measures of depression, anxiety, and fatigue, as well as hair cortisol as an index of chronic stress, were assessed. Twenty breast cancer survivors (BCS) and 31 carefully matched healthy controls participated in the study. After neuropsychological testing and subjective assessments, participants viewed 30 neutral, 30 unpleasant, and 30 pleasant pictures, and ERPs were recorded. Recognition memory was tested 1 week later. BCS reported stronger complaints about cognitive impairments and more symptoms of depression, anxiety, and fatigue. Moreover, they showed elevated hair cortisol levels. Except for verbal memory, cognitive functioning was predominantly in the normative range. Recognition memory performance was decreased in cancer survivors, especially for emotional contents. In ERPs, survivors showed smaller late positive potential amplitudes for unpleasant pictures relative to controls in a later time window, which may indicate less elaborative processing of this material. Taken together, we found cognitive impairments in BCS in verbal memory, impaired emotional picture memory accuracy, and reduced neural activity when breast cancer survivors were confronted with unpleasant materials. Further studies and larger sample sizes, however, are needed to evaluate the relationship between altered emotion processing and reduced memory in BCS in order to develop new treatment strategies.},
  language  = {en}
}
@misc{WirknerLowStrucketal.2017,
  author    = {Wirkner, Janine and Low, Andreas and Struck, Anne-Marie and Hamm, Alfons O. and Weymar, Mathias},
  title     = {DOES AGE INFLUENCE BRAIN POTENTIALS DURING AFFECTIVE PICTURE PROCESSING IN MIDDLE-AGED WOMEN?},
  series = {Psychophysiology : journal of the Society for Psychophysiological Research},
  volume    = {54},
  journal   = {Psychophysiology : journal of the Society for Psychophysiological Research},
  publisher = {Wiley},
  address   = {Hoboken},
  issn      = {0048-5772},
  pages     = {S40 -- S40},
  year      = {2017},
  language  = {en}
}
@misc{WeymarVenturaBortWirkneretal.2019,
  author    = {Weymar, Mathias and Ventura-Bort, Carlos and Wirkner, Janine and Genheimer, Hannah and Wendt, Julia and Hamm, Alfons O.},
  title     = {Effects of Transcutaneous Vagus Vagus Nerve Stimulation (TVNS) on selective attentions and emotional episodic memory : findings from ERP research},
  series = {Psychophysiology : journal of the Society for Psychophysiological Research},
  volume    = {56},
  journal   = {Psychophysiology : journal of the Society for Psychophysiological Research},
  publisher = {Wiley},
  address   = {Hoboken},
  issn      = {0048-5772},
  doi       = {10.1111/psyp.13501},
  pages     = {S12 -- S12},
  year      = {2019},
  abstract  = {Recent research indicates that non- invasive stimulation of the afferent auricular vagal nerve (tVNS) may modulate various cognitive and affec-tive functions, likely via activation of the locus coeruleus- norepinephrine (LC- NE) system. In a series of ERP studies we found that the attention- related P300 component is enhanced during continuous vagal stimula-tion, compared to sham, which is also related to increased salivary alpha amylase levels (a putative indirect marker for central NE activation). In another study, we investigated the effect of continuous tVNS on the late positive potential (LPP), an electrophysiological index for motivated atten-tion toward emotionally evocative cues, and the effects of tVNS on later recognition memory (1- week delay). Here, vagal stimulation prompted earlier LPP differences (300- 500 ms) between unpleasant and neutral scenes. During retrieval, vagal stimulation significantly improved memory performance for unpleasant, but not neutral pictures, compared to sham stimulation, which was also related to enhanced salivary alpha amylase levels. In line, unpleasant images encoded under tVNS compared to sham stimulation also produced enhanced ERP old/new differences (500- 800 ms) during retrieval indicating better recollection. Taken together, our studies suggest that tVNS facilitates attention, learning and episodic memory, likely via afferent projections to the arousal- modulated LC- NE system. We will, however, also show data that point to critical stimulation parameters (likely duration and frequency) that need to be considered when applying tVNS},
  language  = {en}
}
@misc{VenturaBortWirknerGenheimeretal.2018,
  author    = {Ventura-Bort, Carlos and Wirkner, Janine and Genheimer, Hannah and Wendt, Julia and Hamm, Alfons O. and Weymar, Mathias},
  title     = {Effects of Transcutaneous Vagus Nerve Stimulation (tVNS) on the P300 and Alpha-Amylase Level},
  series = {Postprints der Universit{\"a}t Potsdam : Humanwissenschaftliche Reihe},
  journal   = {Postprints der Universit{\"a}t Potsdam : Humanwissenschaftliche Reihe},
  number    = {473},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-419259},
  pages     = {12},
  year      = {2018},
  abstract  = {Recent research suggests that the P3b may be closely related to the activation of the locus coeruleus-norepinephrine (LC-NE) system. To further study the potential association, we applied a novel technique, the non-invasive transcutaneous vagus nerve stimulation (tVNS), which is speculated to increase noradrenaline levels. Using a within-subject cross-over design, 20 healthy participants received continuous tVNS and sham stimulation on two consecutive days (stimulation counterbalanced across participants) while performing a visual oddball task. During stimulation, oval non-targets (standard), normal-head (easy) and rotated-head (difficult) targets, as well as novel stimuli (scenes) were presented. As an indirect marker of noradrenergic activation we also collected salivary alpha-amylase (sAA) before and after stimulation. Results showed larger P3b amplitudes for target, relative to standard stimuli, irrespective of stimulation condition. Exploratory post hoc analyses, however, revealed that, in comparison to standard stimuli, easy (but not difficult) targets produced larger P3b (but not P3a) amplitudes during active tVNS, compared to sham stimulation. For sAA levels, although main analyses did not show differential effects of stimulation, direct testing revealed that tVNS (but not sham stimulation) increased sAA levels after stimulation. Additionally, larger differences between tVNS and sham stimulation in P3b magnitudes for easy targets were associated with larger increase in sAA levels after tVNS, but not after sham stimulation. Despite preliminary evidence for a modulatory influence of tVNS on the P3b, which may be partly mediated by activation of the noradrenergic system, additional research in this field is clearly warranted. Future studies need to clarify whether tVNS also facilitates other processes, such as learning and memory, and whether tVNS can be used as therapeutic tool.},
  language  = {en}
}
@article{VenturaBortWirknerGenheimeretal.2018,
  author    = {Ventura-Bort, Carlos and Wirkner, Janine and Genheimer, Hannah and Wendt, Julia and Hamm, Alfons O. and Weymar, Mathias},
  title     = {Effects of Transcutaneous Vagus Nerve Stimulation (tVNS) on the P300 and Alpha-Amylase Level},
  series = {Frontiers in Human Neuroscience},
  volume    = {12},
  journal   = {Frontiers in Human Neuroscience},
  publisher = {Frontiers Research Foundation},
  address   = {Lausanne},
  issn      = {1662-5161},
  doi       = {10.3389/fnhum.2018.00202},
  pages     = {1 -- 12},
  year      = {2018},
  abstract  = {Recent research suggests that the P3b may be closely related to the activation of the locus coeruleus-norepinephrine (LC-NE) system. To further study the potential association, we applied a novel technique, the non-invasive transcutaneous vagus nerve stimulation (tVNS), which is speculated to increase noradrenaline levels. Using a within-subject cross-over design, 20 healthy participants received continuous tVNS and sham stimulation on two consecutive days (stimulation counterbalanced across participants) while performing a visual oddball task. During stimulation, oval non-targets (standard), normal-head (easy) and rotated-head (difficult) targets, as well as novel stimuli (scenes) were presented. As an indirect marker of noradrenergic activation we also collected salivary alpha-amylase (sAA) before and after stimulation. Results showed larger P3b amplitudes for target, relative to standard stimuli, irrespective of stimulation condition. Exploratory post hoc analyses, however, revealed that, in comparison to standard stimuli, easy (but not difficult) targets produced larger P3b (but not P3a) amplitudes during active tVNS, compared to sham stimulation. For sAA levels, although main analyses did not show differential effects of stimulation, direct testing revealed that tVNS (but not sham stimulation) increased sAA levels after stimulation. Additionally, larger differences between tVNS and sham stimulation in P3b magnitudes for easy targets were associated with larger increase in sAA levels after tVNS, but not after sham stimulation. Despite preliminary evidence for a modulatory influence of tVNS on the P3b, which may be partly mediated by activation of the noradrenergic system, additional research in this field is clearly warranted. Future studies need to clarify whether tVNS also facilitates other processes, such as learning and memory, and whether tVNS can be used as therapeutic tool.},
  language  = {en}
}
@article{WendtHufenbachKoenigetal.2020,
  author    = {Wendt, Julia and Hufenbach, Miriam Catrin and K{\"o}nig, J{\"o}rg and Hamm, Alfons O.},
  title     = {Effects of verbal instructions and physical threat removal prior to extinction training on the return of conditioned fear},
  series = {Scientific Reports},
  volume    = {10},
  journal   = {Scientific Reports},
  publisher = {Macmillan Publishers Limited, part of Springer Nature},
  address   = {London},
  issn      = {2045-2322},
  doi       = {10.1038/s41598-020-57934-7},
  pages     = {14},
  year      = {2020},
  abstract  = {Instructions given prior to extinction training facilitate the extinction of conditioned skin conductance (SCRs) and fear-potentiated startle responses (FPSs) and serve as laboratory models for cognitive interventions implemented in exposure-based treatments of pathological anxiety. Here, we investigated how instructions given prior to extinction training, with or without the additional removal of the electrode used to deliver the unconditioned stimulus (US), affect the return of fear assessed 24 hours later. We replicated previous instruction effects on extinction and added that the additional removal of the US electrode slightly enhanced facilitating effects on the extinction of conditioned FPSs. In contrast, extinction instructions hardly affected the return of conditioned fear responses. These findings suggest that instruction effects observed during extinction training do not extent to tests of return of fear 24 hours later which serve as laboratory models of relapse and improvement stability of exposure-based treatments.},
  language  = {en}
}
@misc{WendtHufenbachKoenigetal.2020,
  author    = {Wendt, Julia and Hufenbach, Miriam Catrin and K{\"o}nig, J{\"o}rg and Hamm, Alfons O.},
  title     = {Effects of verbal instructions and physical threat removal prior to extinction training on the return of conditioned fear},
  series = {Postprints der Universit{\"a}t Potsdam : Humanwissenschaftliche Reihe},
  journal   = {Postprints der Universit{\"a}t Potsdam : Humanwissenschaftliche Reihe},
  number    = {599},
  issn      = {1866-8364},
  doi       = {10.25932/publishup-44479},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-444796},
  pages     = {16},
  year      = {2020},
  abstract  = {Instructions given prior to extinction training facilitate the extinction of conditioned skin conductance (SCRs) and fear-potentiated startle responses (FPSs) and serve as laboratory models for cognitive interventions implemented in exposure-based treatments of pathological anxiety. Here, we investigated how instructions given prior to extinction training, with or without the additional removal of the electrode used to deliver the unconditioned stimulus (US), affect the return of fear assessed 24 hours later. We replicated previous instruction effects on extinction and added that the additional removal of the US electrode slightly enhanced facilitating effects on the extinction of conditioned FPSs. In contrast, extinction instructions hardly affected the return of conditioned fear responses. These findings suggest that instruction effects observed during extinction training do not extent to tests of return of fear 24 hours later which serve as laboratory models of relapse and improvement stability of exposure-based treatments.},
  language  = {en}
}
@article{LischkeJungeHammetal.2018,
  author    = {Lischke, Alexander and Junge, Martin and Hamm, Alfons O. and Weymar, Mathias},
  title     = {Enhanced processing of untrustworthiness in natural faces with neutral expressions},
  series = {Emotion : a new journal from the American Psychological Association},
  volume    = {18},
  journal   = {Emotion : a new journal from the American Psychological Association},
  number    = {2},
  publisher = {American Psychological Association},
  address   = {Washington},
  issn      = {1528-3542},
  doi       = {10.1037/emo0000318},
  pages     = {181 -- 189},
  year      = {2018},
  abstract  = {During social interactions, individuals rapidly and automatically judge others' trustworthiness on the basis of subtle facial cues. To investigate the behavioral and neural correlates of these judgments, we conducted 2 studies: 1 study for the construction and evaluation of a set of natural faces differing in trustworthiness (Study 1: n = 30) and another study for the investigation of event-related potentials (ERPs) in response to this set of natural faces (Study 2: n = 30). Participants of both studies provided highly reliable and nearly identical trustworthiness ratings for the selected faces, supporting the notion that the discrimination of trustworthy and untrustworthy faces depends on distinct facial cues. These cues appear to be processed in an automatic and bottom-up-driven fashion because the free viewing of these faces was sufficient to elicit trustworthiness-related differences in late positive potentials (LPPs) as indicated by larger amplitudes to untrustworthy as compared with trustworthy faces. Taken together, these findings suggest that natural faces contain distinct cues that are automatically and rapidly processed to facilitate the discrimination of untrustworthy and trustworthy faces across various contexts, presumably by enhancing the elaborative processing of untrustworthy as compared with trustworthy faces. (},
  language  = {en}
}