@article{PauliGlotzbachSchoonAndreattaetal.2013,
  author    = {Pauli, Paul and Glotzbach-Schoon, Evelyn and Andreatta, Marta and Reif, Andreas and Ewald, Heike and Tr{\"o}ger, Christian and Baumann, Christian and Deckert, J{\"u}rgen and M{\"u}hlberger, Andreas},
  title     = {Contextual fear conditioning in virtual reality is affected by 5HTTLPR and NPSR1 polymorphisms: effects on fear-potentiated startle},
  series = {Frontiers in Behavioral Neuroscience},
  journal   = {Frontiers in Behavioral Neuroscience},
  doi       = {10.3389/fnbeh.2013.00031},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-96516},
  year      = {2013},
  abstract  = {The serotonin (5-HT) and neuropeptide S (NPS) systems are discussed as important genetic modulators of fear and sustained anxiety contributing to the etiology of anxiety disorders. Sustained anxiety is a crucial characteristic of most anxiety disorders which likely develops through contextual fear conditioning. This study investigated if and how genetic alterations of the 5-HT and the NPS systems as well as their interaction modulate contextual fear conditioning; specifically, function polymorphic variants in the genes coding for the 5-HT transporter (5HTT) and the NPS receptor (NPSR1) were studied. A large group of healthy volunteers was therefore stratified for 5HTTLPR (S+ vs. LL carriers) and NPSR1 rs324981 (T+ vs. AA carriers) polymorphisms resulting in four genotype groups (S+/T+, S+/AA, LL/T+, LL/AA) of 20 participants each. All participants underwent contextual fear conditioning and extinction using a virtual reality (VR) paradigm. During acquisition, one virtual office room (anxiety context, CXT+) was paired with an unpredictable electric stimulus (unconditioned stimulus, US), whereas another virtual office room was not paired with any US (safety context, CXT-). During extinction no US was administered. Anxiety responses were quantified by fear-potentiated startle and ratings. Most importantly, we found a gene × gene interaction on fear-potentiated startle. Only carriers of both risk alleles (S+/T+) exhibited higher startle responses in CXT+ compared to CXT-. In contrast, anxiety ratings were only influenced by the NPSR1 polymorphism with AA carriers showing higher anxiety ratings in CXT+ as compared to CXT-. Our results speak in favor of a two level account of fear conditioning with diverging effects on implicit vs. explicit fear responses. Enhanced contextual fear conditioning as reflected in potentiated startle responses may be an endophenotype for anxiety disorders.},
  language  = {en}
}
@article{ManishNueckelMuehlbergeretal.2013,
  author    = {Manish, Asthana and Nueckel, Katharina and M{\"u}hlberger, Andreas and Neueder, Dorothea and Polak, Thomas and Domschke, Katharina and Deckert, J{\"u}rgen and Herrmann, Martin J.},
  title     = {Effects of transcranial direct current stimulation on consolidation of fear memory},
  series = {Frontiers in Neuropsychiatric Imaging and Stimulation},
  journal   = {Frontiers in Neuropsychiatric Imaging and Stimulation},
  doi       = {10.3389/fpsyt.2013.00107},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-97294},
  year      = {2013},
  abstract  = {It has been shown that applying transcranial direct current stimulation (tDCS) over the dorsolateral prefrontal cortex (DLPFC) influences declarative memory processes. This study investigates the efficacy of tDCS on emotional memory consolidation, especially experimental fear conditioning. We applied an auditory fear-conditioning paradigm, in which two differently colored squares (blue and yellow) were presented as conditioned stimuli (CS) and an auditory stimulus as unconditioned stimulus (UCS). Sixty-nine participants were randomly assigned into three groups: anodal, cathodal, and sham stimulation. The participants of the two active groups (i.e., anodal and cathodal) received tDCS over the left DLPFC for 12 min after fear conditioning. The effect of fear conditioning and consolidation (24 h later) was measured by assessing the skin conductance response (SCR) to the CS. The results provide evidence that cathodal stimulation of the left DLPFC leads to an inhibitory effect on fear memory consolidation compared to anodal and sham stimulation, as indicated by decreased SCRs to CS+ presentation during extinction training at day 2. In conclusion, current work suggests that cathodal stimulation interferes with processes of fear memory consolidation.},
  language  = {en}
}
@article{HohoffGorjiKaiseretal.2013,
  author    = {Hohoff, Christa and Gorji, Ali and Kaiser, Sylvia and Willscher, Edith and Korsching, Eberhard and Ambr{\´e}e, Oliver and Arolt, Volker and Lesch, Klaus-Peter and Sachser, Norbert and Deckert, J{\"u}rgen and Lewejohann, Lars},
  title     = {Effect of Acute Stressor and Serotonin Transporter Genotype on Amygdala First Wave Transcriptome in Mice},
  series = {PLoS ONE},
  volume    = {8},
  journal   = {PLoS ONE},
  number    = {3},
  doi       = {10.1371/journal.pone.0058880},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-131040},
  pages     = {e58880},
  year      = {2013},
  abstract  = {The most prominent brain region evaluating the significance of external stimuli immediately after their onset is the amygdala. Stimuli evaluated as being stressful actuate a number of physiological processes as an immediate stress response. Variation in the serotonin transporter gene has been associated with increased anxiety- and depression-like behavior, altered stress reactivity and adaptation, and pathophysiology of stress-related disorders. In this study the instant reactions to an acute stressor were measured in a serotonin transporter knockout mouse model. Mice lacking the serotonin transporter were verified to be more anxious than their wild-type conspecifics. Genome-wide gene expression changes in the amygdala were measured after the mice were subjected to control condition or to an acute stressor of one minute exposure to water. The dissection of amygdalae and stabilization of RNA was conducted within nine minutes after the onset of the stressor. This extremely short protocol allowed for analysis of first wave primary response genes, typically induced within five to ten minutes of stimulation, and was performed using Affymetrix GeneChip Mouse Gene 1.0 ST Arrays. RNA profiling revealed a largely new set of differentially expressed primary response genes between the conditions acute stress and control that differed distinctly between wild-type and knockout mice. Consequently, functional categorization and pathway analysis indicated genes related to neuroplasticity and adaptation in wild-types whereas knockouts were characterized by impaired plasticity and genes more related to chronic stress and pathophysiology. Our study therefore disclosed different coping styles dependent on serotonin transporter genotype even directly after the onset of stress and accentuates the role of the serotonergic system in processing stressors and threat in the amygdala. Moreover, several of the first wave primary response genes that we found might provide promising targets for future therapeutic interventions of stress-related disorders also in humans.},
  language  = {en}
}