@phdthesis{Stegmann2021,
  author    = {Stegmann, Yannik},
  title     = {Electrocortical mechanisms of sustained attention during the acquisition and interaction of conditioned fear and anxiety},
  doi       = {10.25972/OPUS-23770},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-237700},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2021},
  abstract  = {Adapting defensive behavior to the characteristics of a threatening situation is a fundamental function of the brain. Particularly, threat imminence plays a major role for the organization of defensive responses. Acute threat prompts phasic physiological responses, which are usually associated with an intense feeling of fear. In contrast, diffuse and potentially threatening situations elicit a sustained state of anxious apprehension. Detection of the threatening stimulus defines the key event in this framework, initiating the transition from potential to acute threat. Consequently, attention to threat is crucial for supporting defensive behavior. The functions of attention are finely tuned to the characteristics of a threatening situation. Potential threat is associated with hypervigilance, in order to facilitate threat detection. Once a threatening stimulus has been identified, attention is selectively focused on the source of danger. Even though the concepts of selective attention and hypervigilance to threat are well established, evidence for their neural correlates remain scarce. Therefore, a major goal of this thesis is to elucidate the neural correlates of selective attention to acute threat and hypervigilance during potential threat. A second aim of this thesis is to provide a mechanistic account for the interaction of fear and anxiety. While contemporary models view fear and anxiety as mutually exclusive, recent findings for the neural networks of fear and anxiety suggest potential interactions. In four studies, aversive cue conditioning was used to induce acute threat, while context conditioning served as a laboratory model of potential threat. To quantify neural correlates of selective attention and hypervigilance, steady-state visual evoked potentials (ssVEPs) were measured as an index of visuocortical responding. Study 1 compared visuocortical responses to acute and potential threat for high versus low trait-anxious individuals. All individuals demonstrated enhanced electrocortical responses to the central cue in the acute threat condition, suggesting evidence for the neural correlate of selective attention. However, only low anxious individuals revealed facilitated processing of the contexts in the potential threat condition, reflecting a neural correlate of hypervigilance. High anxious individuals did not discriminate among contexts. These findings contribute to the notion of aberrational processing of potential threat for high anxious individuals. Study 2 and 3 realized orthogonal combinations of cue and context conditioning to investigate potential interactions of fear and anxiety. In contrast to Study 1 and 2, Study 3 used verbal instructions to induce potentially threatening contexts. Besides ssVEPs, threat ratings and skin conductance responses (SCRs) were recorded as efferent indices of defensive responding. None of these studies found further evidence for the neural correlates of hypervigilance and selective attention. However, results for ratings and SCRs revealed additive effects of fear and anxiety, suggesting that fear and anxiety are not mutually exclusive, but interact linearly to organize and facilitate defensive behavior. Study 4 tested ssVEPs to more ecologically valid forms of context conditioning, using flickering video stimuli of virtual offices to establish context representations. Contrary to expectations, results revealed decreased visuocortical responses during sustained presentations of anxiety compared to neutral contexts. A disruption of ssVEP signals eventually suggests interferences by continuously changing video streams which are enhanced as a function of motivational relevance. In summary, this thesis provided evidence for the neural correlates of attention only for isolated forms of fear and anxiety, but not for their interaction. In contrast, an additive interaction model of fear and anxiety for measures of defensive responding offers a new perspective on the topography of defensive behavior.},
  subject      = {Furcht},
  language  = {en}
}
@phdthesis{Genheimer2020,
  author    = {Genheimer, Hannah},
  title     = {The acquisition of anxiety and the impact of transcutaneous vagus nerve stimulation on extinction learning in virtual contexts},
  doi       = {10.25972/OPUS-20639},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-206390},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2020},
  abstract  = {This thesis aims for a better understanding of the mechanisms underlying anxiety as well as trauma- and stressor-related disorders and the development of new therapeutic approaches. I was first interested in the associative learning mechanisms involved in the etiology of anxiety disorders. Second, I explored the therapeutic effects of transcutaneous vagus nerve stimulation (tVNS) as a promising new method to accelerate and stabilize extinction learning in humans. For these purposes, I applied differential anxiety conditioning protocols realized by the implementation of virtual reality (VR). Here, a formerly neutral virtual context (anxiety context, CTX+) is presented whereby the participants unpredictably receive mildly aversive electric stimuli (unconditioned stimulus, US). Another virtual context (safety context, CTX-) is never associated with the US. Moreover, extinction of conditioned anxiety can be modeled by presenting the same contexts without US delivery. When unannounced USs were administered after extinction, i.e. reinstatement, the strength of the "returned" conditioned anxiety can provide information on the stability of the extinction memory. In Study 1, I disentangled the role of elemental and conjunctive context representations in the acquisition of conditioned anxiety. Sequential screenshots of two virtual offices were presented like a flip-book so that I elicited the impression of walking through the contexts. Some pictures of CTX+ were paired with an US (threat elements), but not some other screenshots of the same context (non-threat elements), nor the screenshots depicting CTX- (safety elements). Higher contingency ratings for threat compared to non-threat elements revealed elemental representation. Electro-cortical responses showed larger P100 and early posterior negativity amplitudes elicited by screenshots depicting CTX+ compared to CTX- and suggested conjunctive representation. These results support the dual context representation in anxiety acquisition in healthy individuals. Study 2 addressed the effects of tVNS on the stabilization of extinction learning by using a context conditioning paradigm. Potentiated startle responses as well as higher aversive ratings in CTX+ compared to CTX- indicate successful anxiety conditioning. Complete extinction was found in startle responses and valence ratings as no differentiation between CTX+ and CTX- suggested. TVNS did not affect extinction or reinstatement of anxiety which may be related to the inappropriate transferability of successful stimulation parameters from epilepsy patients to healthy participants during anxiety extinction. Therefore, in Study 3 I wanted to replicate the modulatory effects of tVNS on heart rate and pain perception by the previously used parameters. However, no effects of tVNS were observed on subjective pain ratings, on pain tolerance, or on heart rate. This led to the conclusion that the modification of stimulation parameters is necessary for a successful acceleration of anxiety extinction in humans. In Study 4, I prolonged the tVNS and, considering previous tVNS studies, I applied a cue conditioning paradigm in VR. Therefore, during acquisition a cue (CS+) presented in CTX+ predicted the US, but not another cue (CS-). Both cues were presented in a second context (CTX-) and never paired with the US. Afterward, participants received either tVNS or sham stimulation and underwent extinction learning. I found context-dependent cue conditioning only in valence ratings, which was indicated by lower valence for CS+ compared to CS- in CTX+, but no differential ratings in CTX-. Successful extinction was indicated by equal responses to CS+ and CS-. Interestingly, I found reinstatement of conditioned fear in a context-dependent manner, meaning startle response was potentiated for CS+ compared to CS- only in the anxiety context. Importantly, even the prolonged tVNS had no effect, neither on extinction nor on reinstatement of context-dependent cue conditioning. However, I found first evidence for accelerated physiological contextual extinction due to less differentiation between startles in CTX+ compared to CTX- in the tVNS than in the sham stimulated group. In sum, this thesis first confirms the dual representation of a context in an elemental and a conjunctive manner. Second, though anxiety conditioning and context-dependent cue conditioning paradigms worked well, the translation of tVNS accelerated extinction from rats to humans needs to be further developed, especially the stimulation parameters. Nevertheless, tVNS remains a very promising approach of memory enhancement, which can be particularly auspicious in clinical settings.},
  subject      = {Angst},
  language  = {en}
}
@phdthesis{Karl2019,
  author    = {Karl, Christian},
  title     = {Kontextuelle und differentielle Einfl{\"u}sse auf die neurophysiologische Verarbeitung w{\"u}tender und neutraler Gesichter},
  doi       = {10.25972/OPUS-18306},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-183067},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2019},
  abstract  = {In dieser EEG Untersuchung wurde der Einfluss von zuvor pr{\"a}sentierten Abfolgen w{\"u}tender und neutraler Gesichtsausdr{\"u}cke auf die neurokognitive Verarbeitung eines aktuell wahrgenommenen Gesichts unter Ber{\"u}cksichtigung des modulierenden Effekts der individuellen {\"A}ngstlichkeit, sowie eines sozial stressenden Kontextes und einer erh{\"o}hten kognitiven Auslastung erforscht. Die Ergebnisse lieferten bereits auf der Ebene der basalen visuellen Gesichtsanalyse Belege f{\"u}r eine parallele Verarbeitung und Integration von strukturellen und emotionalen Gesichtsinformationen. Zudem konnte schon in dieser fr{\"u}hen Phase ein genereller kontextueller Einfluss von Gesichtssequenzen auf die kognitive Gesichtsverarbeitung nachgewiesen werden, welcher sogar in sp{\"a}teren Phasen der kognitiven Verarbeitung noch zunahm. Damit konnte nachgewiesen werden, dass die zeitliche Integration, d.h. die spezifische Abfolge wahrgenommener Gesichter eine wichtige Rolle f{\"u}r die kognitive Evaluation des aktuell perzipierten Gesichtes spielt. Diese Ergebnisse wurden zudem in einer Revision des Gesichtsverarbeitungsmodells von Haxby und Kollegen verordnet und in einer sLORETA Analyse dargestellt. Die Befunde zur individuellen {\"A}ngstlichkeit und kognitiven Auslastung best{\"a}tigten außerdem die Attentional Control Theorie und das Dual Mechanisms of Control Modell.},
  subject      = {Visuelle Wahrnehmung},
  language  = {de}
}
@phdthesis{Kastner2015,
  author    = {Kastner, Anna Katharina},
  title     = {Attention mechanisms in contextual anxiety and cued fear and their influence on processing of social cues},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-123747},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2015},
  abstract  = {Anxiety is an affective state characterized by a sustained, long-lasting defensive response, induced by unpredictable, diffuse threat. In comparison, fear is a phasic response to predictable threat. Fear can be experimentally modeled with the help of cue conditioning. Context conditioning, in which the context serves as the best predictor of a threat due to the absence of any conditioned cues, is seen as an operationalization of sustained anxiety. This thesis used a differential context conditioning paradigm to examine sustained attention processes in a threat context compared to a safety context for the first time. In three studies, the attention mechanisms during the processing of contextual anxiety were examined by measuring heart rate responses and steady-state-visually evoked potentials (ssVEPs). An additional focus was set on the processing of social cues (i.e. faces) and the influence of contextual information on these cues. In a last step, the correlates of sustained anxiety were compared to evoked responses by phasic fear, which was realized in a previously established paradigm combining predictable and unpredictable threat. In the first study, a contextual stimulus was associated with an aversive loud noise, while a second context remained unpaired. This conditioning paradigm created an anxiety context (CTX+) and a safety context (CTX-). After acquisition, a social agent vs. an object was presented as a distractor in both contexts. Heart rate and cortical responses, with ssVEPs by using frequency tagging, to the contexts and the distractors were assessed. Results revealed enhanced ssVEP amplitudes for the CTX+ compared to the CTX- during acquisition and during presentation of distractor stimuli. Additionally, the heart rate was accelerated in the acquisition phase, followed by a heart rate deceleration as a psychophysiological marker of contextual anxiety. Study 2 used the same context conditioning paradigm as Study 1. In contrast to the first study, persons with different emotional facial expressions were presented in the anxiety and safety contexts in order to compare the differential processing of these cues within periods of threat and safety. A similar anxiety response was found in the second study, although only participants who Abstract VIII were aware of the contingency between contexts and aversive event showed a sensory amplification of the threat context, indicated by heart rate response and ssVEP activation. All faces irrespective of their emotional expression received increased attentional resources when presented within the anxiety context, which suggests a general hypervigilance in anxiety contexts. In the third study, the differentiation of predictable and unpredictable threat as an operationalization of fear and anxiety was examined on a cortical and physiological level. In the predictable condition, a social cue was paired with an aversive event, while in the unpredictable condition the aversive event remained unpaired with the respective cue. A fear response to the predictable cue was found, indicated by increased oscillatory response and accelerated heart rate. Both predictable and unpredictable threat yielded increased ssVEP amplitudes evoked by the context stimuli, while the response in the unpredictable context showed longer-lasting ssVEP activation to the threat context. To sum up, all three studies endorsed anxiety as a long-lasting defensive response. Due to the unpredictability of the aversive events, the individuals reacted with hypervigilance in the anxiety context, reflected in a facilitated processing of sensory information and an orienting response. This hypervigilance had an impact on the processing of novel cues, which appeared in the anxiety context. Considering the compared stimuli categories, the stimuli perceived in a state of anxiety received increased attentional resources, irrespective of the emotional arousal conveyed by the facial expression. Both predictable and unpredictable threat elicited sensory amplification of the contexts, while the response in the unpredictable context showed longer-lasting sensory facilitation of the threat context.},
  subject      = {Angst},
  language  = {en}
}
@phdthesis{Ewald2014,
  author    = {Ewald, Heike},
  title     = {Influence of context and contingency awareness on fear conditioning - an investigation in virtual reality},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-111226},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2014},
  abstract  = {Fear conditioning is an efficient model of associative learning, which has greatly improved our knowledge of processes underlying the development and maintenance of pathological fear and anxiety. In a differential fear conditioning paradigm, one initially neutral stimulus (NS) is paired with an aversive event (unconditioned stimulus, US), whereas another stimulus does not have any consequences. After a few pairings the NS is associated with the US and consequently becomes a conditioned stimulus (CS+), which elicits a conditioned response (CR). The formation of explicit knowledge of the CS/US association during conditioning is referred to as contingency awareness. Findings about its role in fear conditioning are ambiguous. The development of a CR without contingency awareness has been shown in delay fear conditioning studies. One speaks of delay conditioning, when the US coterminates with or follows directly on the CS+. In trace conditioning, a temporal gap or "trace interval" lies between CS+ and US. According to existing evidence, trace conditioning is not possible on an implicit level and requires more cognitive resources than delay conditioning. The associations formed during fear conditioning are not exclusively associations between specific cues and aversive events. Contextual cues form the background milieu of the learning process and play an important role in both acquisition and the extinction of conditioned fear and anxiety. A common limitation in human fear conditioning studies is the lack of ecological validity, especially regarding contextual information. The use of Virtual Reality (VR) is a promising approach for creating a more complex environment which is close to a real life situation. I conducted three studies to examine cue and contextual fear conditioning with regard to the role of contingency awareness. For this purpose a VR paradigm was created, which allowed for exact manipulation of cues and contexts as well as timing of events. In all three experiments, participants were guided through one or more virtual rooms serving as contexts, in which two different lights served as CS and an electric stimulus as US. Fear potentiated startle (FPS) responses were measured as an indicator of implicit fear conditioning. To test whether participants had developed explicit awareness of the CS-US contingencies, subjective ratings were collected. The first study was designed as a pilot study to test the VR paradigm as well as the conditioning protocol. Additionally, I was interested in the effect of contingency awareness. Results provided evidence, that eye blink conditioning is possible in the virtual environment and that it does not depend on contingency awareness. Evaluative conditioning, as measured by subjective ratings, was only present in the group of participants who explicitly learned the association between CS and US. To examine acquisition and extinction of both fear associated cues and contexts, a novel cue-context generalization paradigm was applied in the second study. Besides the interplay of cues and contexts I was again interested in the effect of contingency awareness. Two different virtual offices served as fear and safety context, respectively. During acquisition, the CS+ was always followed by the US in the fear context. In the safety context, none of the lights had any consequences. During extinction, a additional (novel) context was introduced, no US was delivered in any of the contexts. Participants showed enhanced startle responses to the CS+ compared to the CS- in the fear context. Thus, discriminative learning took place regarding both cues and contexts during acquisition. This was confirmed by subjective ratings, although only for participants with explicit contingency awareness. Generalization of fear to the novel context after conditioning did not depend on awareness and was observable only on trend level. In a third experiment I looked at neuronal correlates involved in extinction of fear memory by means of functional magnetic resonance imaging (fMRI). Of particular interest were differences between extinction of delay and trace fear conditioning. I applied the paradigm tested in the pilot study and additionally manipulated timing of the stimuli: In the delay conditioning group (DCG) the US was administered with offset of one light (CS+), in the trace conditioning group (TCG) the US was presented 4s after CS+ offset. Most importantly, prefrontal activation differed between the two groups. In line with existing evidence, the ventromedial prefrontal cortex (vmPFC) was activated in the DCG. In the TCG I found activation of the dorsolateral prefrontal cortex (dlPFC), which might be associated with modulation of working memory processes necessary for bridging the trace interval and holding information in short term memory. Taken together, virtual reality proved to be an elegant tool for examining human fear conditioning in complex environments, and especially for manipulating contextual information. Results indicate that explicit knowledge of contingencies is necessary for attitude formation in fear conditioning, but not for a CR on an implicit level as measured by FPS responses. They provide evidence for a two level account of fear conditioning. Discriminative learning was successful regarding both cues and contexts. Imaging results speak for different extinction processes in delay and trace conditioning, hinting that higher working memory contribution is required for trace than for delay conditioning.},
  subject      = {Klassische Konditionierung},
  language  = {en}
}
@phdthesis{Shiban2013,
  author    = {Shiban, Youssef},
  title     = {Attenuating Renewal following Exposure Therapy : Mechanisms of Exposure in Multiple Contexts and its Influence on the Renewal of Fear: Studies in Virtual Reality},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-76673},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2013},
  abstract  = {„Renewal" bezeichnet das Wiederauftreten von Angst nach erfolgreicher Expositionstherapie in Folge einer erneuten Konfrontation mit dem phobischen Stimulus in einem neuen, sich vom Expositionskontext unterscheidenden Kontext. Bouton (1994) zufolge deutet diese Angstr{\"u}ckkehr durch einen Kontextwechsel darauf hin, dass die Angst nicht gel{\"o}scht wurde. Stattdessen wurde w{\"a}hrend der Expositionssitzung eine neue Assoziation gelernt, die das gef{\"u}rchtete Objekt mit „keiner Angst", also den konditionierten Reiz (conditioned stimulus, CS) mit „keinem unkonditionierten Reiz" (no unconditioned stimulus, no US), verbindet. Bouton argumentiert weiter, dass diese Assoziation kontextabh{\"a}ngig ist, wodurch Effekte wie Angst-Renewal erkl{\"a}rt werden k{\"o}nnen. Da in einem neuen Kontext die CS-no US-Assoziation nicht aktiviert wird, wird die Angst auch nicht gehemmt. Die Kontextabh{\"a}ngigkeit der CS-no US-Assoziation wurde in mehreren Studien belegt (Balooch \& Neumann, 2011; Siavash Bandarian Balooch, Neumann, \& Boschen, 2012; Culver, Stoyanova, \& Craske, 2011; Kim \& Richardson, 2009; Neumann \& Kitlertsirivatana, 2010). Aktuell konzentriert sich die Forschung zur Therapie von Angstst{\"o}rungen auf die Frage, wie Angst reduziert und gleichzeitig ein R{\"u}ckfall verhindert werden kann. Hierzu werden verschiedene Expositionsprotokolle untersucht, wie zum Beispiel (1) Exposition in mehreren Kontexten (multiple contexts exposure, MCE), um Renewal zu reduzieren (z.B. Balooch \& Neumann, 2011); (2) verl{\"a}ngerte Exposition (prolonged exposure, PE), um die hemmende Assoziation w{\"a}hrend des Extinktionslernes zu st{\"a}rken (z.B. Thomas, Vurbic, \& Novak, 2009) und (3) Rekonsolidierungs-Updates (reconsolidation update, RU), die den Rekonsolidierungsprozess durch eine kurze Exposition des CS+ vor der eigentlichen Exposition aktualisieren sollen (Schiller et al., 2010). Bisher liegen jedoch nur sehr wenige Studien vor, die diese neuen Expositionsprotokolle an klinischen Stichproben untersucht haben, und - soweit bekannt - keine Studie, welche die Wirkmechanismen dieser Protokolle an einer klinischen Stichprobe erforscht. Die vorliegende Dissertation hat drei Ziele. Das erste Ziel besteht darin zu pr{\"u}fen, ob Expositionstherapie in multiplen Kontexten die Wahrscheinlichkeit von Renewal reduziert. Das zweite Ziel ist die Untersuchung der Mechanismen, die dem Effekt der Exposition in multiplen Kontexten zugrunde liegen und das dritte ist den Kontext im Zusammenhang mit Konditionierung und Extinktion zu konzeptualisieren. Insgesamt wurden drei Studien durchgef{\"u}hrt. Die erste Studie untersuchte den Effekt von Exposition in multiplen Kontexten auf Renewal, die zweite und dritte Studie die Wirkmechanismen von MCE. In der ersten Studie wurden spinnenphobische Probanden (N = 30) viermal mit einer virtuellen Spinne konfrontiert. Die Expositionstrials wurden entweder in einem gleichbleibenden Kontext oder in vier verschiedenen Kontexten durchgef{\"u}hrt. Am Ende der Sitzung absolvierten alle Teilnehmer einen virtuellen Renewaltest, bei dem die virtuelle Spinne in einem neuen Kontext gezeigt wurde, und einen in vivo Verhaltensvermeidungstest (behavioral avoidance test, BAT) mit einer echten Spinne. Die Ergebnisse zeigten, dass Probanden, welche die vier Expositionstrials in unterschiedlichen Kontexten erfuhren, weniger Angst, sowohl im virtuellen Renewaltest als auch im BAT, erlebten. In dieser Studie konnte die Wirksamkeit von MCE f{\"u}r die Reduktion von Renewal erfolgreich nachgewiesen werden. Studie 2 (N = 35) untersuchte die Wirkmechanismen von MCE in einem differentiellen Konditionierungsparadigma. Die Extinktion wurde in multiplen Kontexten durchgef{\"u}hrt. Hierbei war das Ziel, eine {\"a}hnliche Verminderung von Renewal wie in Studie 1 nachzuweisen. Der Extinktion folgten zwei Tests, mit dem Ziel m{\"o}gliche hemmende Effekte des Kontexts, die w{\"a}hrend der Extinktionsphase erworben wurden, aufzudecken. Bez{\"u}glich des Effektes von MCE wurden drei Hypothesen aufgestellt: (1) Der Extinktionskontext wird mit der Exposition assoziiert, fungiert folglich w{\"a}hrend der Extinktion als Sicherheitssignal und konkurriert daher mit dem Sicherheitslernen des CS. Dies f{\"u}hrt zu einem verminderten Extinktionseffekt auf den CS, wenn die Extinktion nur in einem Kontext durchgef{\"u}hrt wird. (2) Die Elemente im Extinktionskontext (z.B. Raumfarbe, M{\"o}bel) stehen im Zusammenhang mit der CS-no US-Assoziation und erinnern daher an die Extinktion, was zu einer gr{\"o}ßeren Angsthemmung f{\"u}hrt, wenn sie w{\"a}hrend eines Tests gezeigt werden. (3) Nach der emotionalen Prozesstheorie (emotional process theory; Bouton, 1994; Foa et al., 1996) bestimmen die Therapieprozessfaktoren die St{\"a}rke des Renewals. Beispielsweise korrelieren initiale Angstaktivierung, Aktivierung in und zwischen den Sitzungen mit der St{\"a}rke des Renewals. Jedoch waren in dieser Studie keine Unterschiede zwischen den Gruppen im Renewaltest zu beobachten, weswegen die Ergebnisse der zwei Nachtests nicht zu interpretieren sind. Das Ziel von Studie 3 (N = 61) war es, das Konzept des Kontexts im Rahmen von Konditionierung und Exposition zu definieren. In Studie 3 wurde das Auftreten der Generalisierungsabnahme (generalization decrement) genutzt, bei der eine konditionierte Reaktion infolge eines Kontextwechsels nur reduziert auftritt. Auf diesem Weg kann Kontext{\"a}hnlichkeit quantifiziert werden. Nach einer Akquisitonsphase in einem Kontext wurden die Teilnehmer in einem von drei verschiedenen Kontexten getestet. Zwei dieser Kontexte unterschieden sich nur in einer Dimension (Anordnung der Objekte vs. Objekteigenschaften). Die dritte Gruppe wurde im Akquisitonskontext getestet und diente als Kontrollgruppe. Es fanden sich jedoch keine Unteschiede zwischen den Gruppen in den Testphasen. Eine m{\"o}gliche Erkl{\"a}rung ist die Neuartigkeit des Testkontextes. Teilnehmer, die nach der Extinktion einem neuen Kontext ausgesetzt waren, erwarteten in einem anderen Kontext eine zweite Extinktionsphase und zeigten daher mehr statt weniger Angst als erwartet.},
  subject      = {Angst},
  language  = {en}
}
@phdthesis{Bruetting2013,
  author    = {Br{\"u}tting, Johanna},
  title     = {Psychotherapie spezifischer Phobien: Die Bedeutung der Angstaktivierung f{\"u}r Therapieprozess und Therapieerfolg},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-80578},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2013},
  abstract  = {In der vorliegenden Arbeit wurde untersucht, inwiefern die Angstaktivierung Einfluss auf den Therapieprozess und den Therapieerfolg bei der Behandlung spezifischer Phobien hat. Obwohl expositionsbasierte Therapieverfahren nachweislich effektiv sind und vor allem bei der Behandlung spezifischer Phobien als die Methode der Wahl gelten, sind deren genauen Wirkmechanismen doch noch nicht v{\"o}llig gekl{\"a}rt. In zwei empirischen Studien wurde hier die von Foa und Kozak (1986, 1991) in der „Emotional Processing Theory" als notwendig postulierte Rolle der Angstaktivierung w{\"a}hrend der Exposition untersucht. In der ersten Studie wurde auf Grundlage tier- und humanexperimenteller Befunde untersucht, ob durch eine Reaktivierung der Angst und darauffolgende Exposition innerhalb eines bestimmten Zeitfensters (= Rekonsolidierungsfenster) die R{\"u}ckkehr der Angst verhindert werden kann. Ziel dieser Untersuchung war die {\"U}bertragung bisheriger Ergebnisse aus Konditionierungsstudien auf eine klinische Stichprobe. Die spinnenphobischen Untersuchungsteilnehmer (N = 36) wurden randomisiert entweder der Reaktivierungsgruppe (RG) oder einer Standardexpositionsgruppe (SEG) zugewiesen. Die RG bekam vor der Exposition in virtueller Realit{\"a}t (VRET) f{\"u}nf Sekunden lang einen Reaktivierungsstimulus - eine virtuelle Spinne - dargeboten, woraufhin zehn Minuten standardisierte Wartezeit folgte. In der SEG wurde die Angst vor der Exposition nicht reaktiviert. 24 Stunden nach der VRET wurde in einem Test die spontane R{\"u}ckkehr der Angst erfasst. Entgegen der Annahmen f{\"u}hrte die Reaktivierung vor der VRET nicht zu einer geringeren R{\"u}ckkehr der Angst in der Testsitzung 24 Stunden sp{\"a}ter. Die Angst kehrte in keiner der beiden Versuchsgruppen zur{\"u}ck, was sich bez{\"u}glich subjektiver Angstratings, f{\"u}r Verhaltensdaten und auch f{\"u}r physiologische Maße zeigte. Auch zeigte sich ein grunds{\"a}tzlich positiver Effekt der Behandlung, bei der im Anschluss noch eine Exposition in vivo stattfand. Ein Follow-Up nach sechs Monaten ergab eine weitere Reduktion der Spinnenangst. Die Ergebnisse legen nahe, dass sich die experimentellen Befunde zu Rekonsolidierungsprozessen aus Konditionierungsstudien nicht einfach auf ein Therapiesetting und die Behandlung spezifischer Phobien {\"u}bertragen lassen. Die zweite Studie befasste sich mit der Frage, ob Koffein die initiale Angstaktivierung erh{\"o}hen kann und ob sich dies positiv auf den Therapieerfolg auswirkt. Die spinnenphobischen Studienteilnehmer (N = 35) wurden in einem doppelblinden Versuchsdesign entweder der Koffeingruppe (KOFG) oder der Placebogruppe (PG) zugeordnet. Die KOFG erhielt eine Stunde vor Beginn der VRET eine Koffeintablette mit 200 mg Koffein, die PG erhielt als {\"A}quivalent zur gleichen Zeit eine Placebotablette. Eine Analyse der Speichelproben der Probanden ergab, dass sich die Koffeinkonzentration durch die Koffeintablette signifikant erh{\"o}hte. Dies f{\"u}hrte jedoch nicht, wie erwartet, zu einer h{\"o}heren Angstaktivierung w{\"a}hrend der VRET, weshalb unter anderem diskutiert wird, ob evtl. die Koffeinkonzentration zu niedrig war, um anxiogen zu wirken. Dennoch profitierten die Teilnehmer beider Versuchsgruppen von unserem Behandlungsangebot. Die Spinnenangst reduzierte sich signifikant {\"u}ber vier Sitzungen hinweg. Diese Reduktion blieb stabil bis zum Follow-Up drei Monate nach Studienende. Zusammengefasst l{\"a}sst sich zur optimalen H{\"o}he der Angstaktivierung aufgrund der hier durchgef{\"u}hrten beiden Studien keine exakte Aussage machen, da sich die Versuchsgruppen in beiden Studien hinsichtlich der H{\"o}he der Angstaktivierung zu Beginn (und auch w{\"a}hrend) der Exposition nicht unterschieden. Es l{\"a}sst sich aber festhalten, dass die VRET und auch die in vivo Exposition in beiden Studien effektiv Angst ausl{\"o}sten und dass sich die Angst in beiden Gruppen signifikant bis zu den Follow-Ups (sechs bzw. drei Monate nach Studienende) signifikant reduzierte. Die Behandlung kann also als erfolgreich angesehen werden. M{\"o}gliche andere Wirkfaktoren der Expositionstherapie, wie z.B. die Rolle der wahrgenommenen Kontrolle werden neben der H{\"o}he der Angstaktivierung diskutiert.},
  subject      = {Psychotherapie},
  language  = {de}
}
@phdthesis{Gerdes2008,
  author    = {Gerdes, Antje B. M.},
  title     = {Preferential Processing of Phobic Cues : Attention and Perception in Spider Phobic Patients},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-28684},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2008},
  abstract  = {Cognitive views of the psychopathology of anxiety propose that attentional biases toward threatening information play a substantial role in the disorders' etiology and maintenance. For healthy subjects, converging evidence show that threatening stimuli attract attention and lead to enhanced activation in visual processing areas. It is assumed that this preferential processing of threat occurs at a preattentive level and is followed by fast attentional engagement. High-anxious individuals show augmented tendencies to selectively attend toward fear-relevant cues (Mathews, 1990) and exhibit elevated neural processing of threatening cues compared to non-anxious individuals (Dilger et al., 2003). Regarding attentional biases in high-anxious subjects, it remains unanswered up to now whether initial engagement of attention toward threat or difficulties to disengage from threat is an underlying mechanism. Furthermore, little is known whether the preferential (attentive) processing of threatening cues does influence perceptional outcomes of anxious subjects. In order to directly study separate components of attentional bias the first study of this dissertation was a combined reaction time and eye-tracking experiment. Twenty one spider phobic patients and 21 control participants were instructed to search for a neutral target while ignoring task-irrelevant abrupt-onset distractor circles which contained either a small picture of a spider (phobic), a flower (non-phobic, but similar to spiders in shape), a mushroom (non-phobic, and not similar to spiders in shape), or small circles with no picture. As expected, patients' reaction times to targets were longer on trials with spider distractors. However, analyses of eye movements revealed that this was not due to attentional capture by spider distractors; patients more often fixated on all distractors with pictures. Instead, reaction times were delayed by longer fixation durations on spider distractors. This result does not support automatic capture of attention by phobic cues but suggests that phobic patients fail to disengage attention from spiders. To assess whether preferential processing of phobic cues differentially affects visual perception in phobic patients compared to healthy controls, the second study of this dissertation used a binocular rivalry paradigm, where two incompatible pictures were presented to each eye. These pictures cannot be merged to a meaningful percept and temporarily, one picture predominates in conscious perception whereas the other is suppressed. 23 spider phobic patients and 20 non-anxious control participants were shown standardized pictures of spiders or flowers, each paired with a neutral pattern under conditions of binocular rivalry. Their task was to continuously indicate the predominant percept by key presses. Analyses show that spider phobic patients perceived the spider picture more often and longer as dominant compared to non-anxious control participants. Thus, predominance of phobic cues in binocular rivalry provides evidence that preferential processing of fear-relevant cues in the visual system actually leads to superior perception. In combination both studies support the notion that phobic patients process phobic cues preferentially within the visual system resulting in enhanced attention and perception. At early stages of visual processing, this is mainly reflected by delayed attentional disengagement and across time, preferential processing leads to improved perception of threat cues.},
  subject      = {Phobie},
  language  = {en}
}