@phdthesis{Schwarzmeier2023,
  author    = {Schwarzmeier, Hanna},
  title     = {From fear extinction to exposure therapy: neural mechanisms and moderators of extinction},
  doi       = {10.25972/OPUS-22330},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-223304},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2023},
  abstract  = {Emotional-associative learning processes such as fear conditioning and extinction are highly relevant to not only the development and maintenance of anxiety disorders (ADs), but also to their treatment. Extinction, as the laboratory analogue to behavioral exposure, is assumed a core process underlying the treatment of ADs. Although exposure-based treatments are highly effective for the average patient suffering from an AD, there remains a gap in treatment efficacy with over one third of patients failing to achieve clinically significant symptom relief. There is ergo a pressing need for intensified research regarding the underlying neural mechanisms of aberrant emotional-associative learning processes and the neurobiological moderators of treatment (non-)response in ADs. The current thesis focuses on different applications of the fundamental principles of fear conditioning and extinction by using two example cases of ADs from two different multicenter trials. First, we targeted alterations in fear acquisition, extinction, and its recall as a function of psychopathology in panic disorder (PD) patients compared to healthy subjects using fMRI. Second, exposure-based therapy and pre-treatment patient characteristics exerting a moderating influence on this essential learning process later on (i.e. treatment outcome) were examined using multimodal functional and structural neuroimaging in spider phobia. We observed aberrations in emotional-associative learning processes in PD patients compared to healthy subjects indicated by an accelerated fear acquisition and an attenuated extinction recall. Furthermore, pre-treatment differences related to defensive, regulatory, attentional, and perceptual processes may exert a moderating influence on treatment outcome to behavioral exposure in spider phobia. Although the current results need further replication, on an integrative meta level, results point to a hyperactive defensive network system and deficient emotion regulation processes (including extinction processes) and top-down control in ADs. This speaks in favor of transdiagnostic deficits in important functional domains in ADs. Deficits in transdiagnostic domains such as emotion regulation processes could be targeted by enhancing extinction learning or by means of promising tools like neurofeedback. The detection of pre-treatment clinical response moderators, for instance via machine learning frameworks, may help in supporting clinical decision making on individually tailored treatment approaches or, respectively, to avoid ineffective treatment and its related financial costs. In the long run, the identification of neurobiological markers which are capable of detecting non-responders a priori represents an ultimate goal.},
  subject      = {Extinktion},
  language  = {en}
}
@phdthesis{Aster2023,
  author    = {Aster, Hans-Christoph},
  title     = {Characterization of subgroups in fibromyalgia syndrome},
  doi       = {10.25972/OPUS-31304},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-313049},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2023},
  abstract  = {The present cumulative dissertation summarizes three clinical studies, which examine subgroups of patients within the fibromyalgia syndrome (FMS). FMS entails chronic pain and associated symptoms, and its pathophysiology is incompletely understood (1). Previous studies show that there is a subgroup of patients with FMS with objective histological pathology of the small nerve fibers of the peripheral nervous system (PNS). Another subgroup of FMS patients does not show any signs of pathological changes of the small nerve fibers. The aim of this dissertation was to compare FMS patients with healthy controls, and these two FMS subgroups for differences in the central nervous system (CNS) in order to explore possible interactions between PNS and the CNS. Regarding the CNS, differences of FMS patients with healthy controls have already been found in studies with small sample sizes, but no subgroups have yet been identified. Another aim of this thesis was to test whether the subgroups show a different response to different classes of pain medication. The methods used in this thesis are structural and functional magnetic resonance imaging (MRI), magnetic resonance diffusion imaging and magnetic resonance spectroscopy. For the evaluation of clinical symptoms, we used standardized questionnaires. The subgroups with and without pathologies of the PNS were determined by skin biopsies of the right thigh and lower leg based on the intraepidermal nerve fiber density (IENFD) of the small nerve fibers. 1) In the first MRI study, 43 female patients with the diagnosis of FMS and 40 healthy control subjects, matched in age and body mass index, were examined with different MRI sequences. Cortical thickness was investigated by structural T1 imaging, white matter integrity by diffusion tensor imaging and functional connectivity within neuronal networks by functional resting state MRI. Compared to the controls, FMS patients had a lower cortical volume in bilateral frontotemporoparietal regions and the left insula, but a higher cortical volume in the left pericalcarine cortex. Compared to the subgroup without PNS pathology, the subgroup with PNS pathology had lower cortical volume in both pericalcarine cortices. Diffusion tensor imaging revealed an increased fractional anisotropy (FA) of FMS patients in corticospinal pathways such as the corona radiata, but also in regions of the limbic systems such as the fornix and cingulum. Subgroup comparison again revealed lower mean FA values of the posterior thalamic radiation and the posterior limb of the left internal capsule in the subgroup with PNS pathology. In the functional connectivity analysis FMS patients, compared to controls, showed a hypoconnectivity between the right median frontal gyrus and the posterior cerebellum and the right crus cerebellum, respectively. In the subgroup comparisons, the subgroup with PNS pathology showed a hyperconnectivity between both inferior frontal gyri, the right posterior parietal cortex and the right angular gyrus. In summary, these results show that differences in brain morphology and functional connectivity exist between FMS patients with and without PNS pathology. These differences were not associated with symptom duration or severity and, in some cases, have not yet been described in the context of FMS. The differences in brain morphology and connectivity between subgroups could also lead to a differential response to treatment with centrally acting drugs. Further imaging studies with FMS patients should take into account this heterogeneity of FMS patient cohorts. 2) Following the results from the first MRI study, drug therapies of FMS patients and their treatment response were compared between PNS subgroups. As there is no licensed drug for FMS in Europe, the German S3 guideline recommends amitriptyline, duloxetine and pregabalin for temporary use. In order to examine the current drug use in FMS patients in Germany on a cross-sectional basis, 156 patients with FMS were systematically interviewed. The drugs most frequently used to treat pain in FMS were non-steroidal anti-inflammatory drugs (NSAIDs) (28.9\%), metamizole (15.4\%) and amitriptyline (8.8\%). Pain relief assessed by patients on a numerical rating scale from 0-10 averaged 2.2 points for NSAIDs, 2.0 for metamizole and 1.5 for amitriptyline. Drugs that were discontinued for lack of efficacy and not for side effects were acetaminophen (100\%), flupirtine (91.7\%), selective serotonin reuptake inhibitors (81.8\%), NSAIDs (83.7\%) and weak opioids (74.1\%). Patients were divided into subgroups with and without PNS pathology as determined by skin biopsies. We found no differences in drug use and effect between the subgroups. Taken together, these results show that many FMS patients take medication that is not in accordance with the guidelines. The reduction of symptoms was best achieved with metamizole and NSAIDs. Further longitudinal studies on medication in FMS are necessary to obtain clearer treatment recommendations. 3) Derived from previous pharmacological and imaging studies (with smaller case numbers), there is a hypothesis in the FMS literature that hyperreactivity of the insular cortex may have an impact on FMS. The hyperreactivity seems to be due to an increased concentration of the excitatory neurotransmitter glutamate in the insular cortex of FMS patients. The hypothesis is supported by magnetic resonance spectroscopy studies with small number of cases, as well as results from pharmacological studies with glutamate-inhibiting medication. Studies from animal models have also shown that an artificially induced increase in glutamate in the insular cortex can lead to reduced skin innervation. Therefore, the aim of this study was to compare glutamate and GABA concentrations in the insular cortex of FMS patients with those of healthy controls using magnetic resonance imaging. There was no significant difference of both neurotransmitters between the groups. In addition, there was no correlation between the neurotransmitter concentrations and the severity of clinical symptoms. There were also no differences in neurotransmitter concentrations between the subgroups with and without PNS pathology. In conclusion, our study could not show any evidence of a correlation of glutamate and GABA concentrations with the symptoms of FMS or the pathogenesis of subgroups with PNS pathologies.},
  subject      = {Fibromyalgie},
  language  = {en}
}
@phdthesis{Mittermeier2023,
  author    = {Mittermeier, Anna Barbara},
  title     = {Furchtgeneralisierung bei Kindern und Jugendlichen mit internalisierenden St{\"o}rungen},
  doi       = {10.25972/OPUS-28265},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-282658},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2023},
  abstract  = {In vorgegangenen Studien wurde bei erwachsenen Patienten mit Angstst{\"o}rungen eine verst{\"a}rkte Furchtgeneralisierung, eine eingeschr{\"a}nkte F{\"a}higkeit zur Reizdiskrimination sowie eine ver{\"a}nderte Aufmerksamkeitsverteilung nachgewiesen. In einer gesunden Studienpopulation konnte bei Kindern eine st{\"a}rkere Furchtgeneralisierung nachgewiesen werden als bei Erwachsenen. Ihre Generalisierungsgradienten gleichen denen von Erwachsenen mit Angstst{\"o}rung. M{\"o}glicherweise haben gest{\"o}rte Lernprozesse in der Kindheit somit langfristige Effekte auf die Entwicklung von Angstst{\"o}rungen. Obwohl die Vorg{\"a}nge des Furchtlernens im Kindesalter entscheidend f{\"u}r das Verst{\"a}ndnis von Angstst{\"o}rungen sind, gibt es kaum Studien in dieser Altersgruppe. Die vorliegende Studie untersucht die Zusammenh{\"a}nge von Furchtgeneralisierung und Aufmerksamkeitsprozessen in einer klinischen Population mit internalisierender St{\"o}rung im Kindes- und Jugendalter. Hierzu durchliefen Kinder und Jugendliche mit internalisierender St{\"o}rung (n= 49) sowie gesunde Kontrollen (n=48) im Alter von 9 bis 17 Jahre ein Furcht-generalisierungsparadigma mit Diskriminationstraining sowie einen modifizierten Dotprobe mit integriertem Eyetracking. Die {\"A}ngstlichkeit wurde mittels verschiedener Angstfrageb{\"o}gen gemessen. Im Generalisierungsparadigma wurden zwei weibliche Gesichter mit neutralem Gesichtsausdruck als Stimuli verwendet, die entweder mit (CS+) oder ohne (CS-) einem 95dB lauten Schrei sowie einem angsterf{\"u}llten Gesichtsausdruck gezeigt wurden. Zur Messung der Furchtreaktion wurden subjektive Ratings f{\"u}r Arousal, Valenz und Kontingenz erfasst, zudem wurde die Hautleitf{\"a}higkeit gemessen. Zur Auswertung des Dotprobes wurden die Reaktionszeiten und die Initialsakkade erfasst. Die statistische Analyse des Furchtgeneralisierungsparadigmas sowie des Dotprobe-Paradigmas wurde mittels Multivarianzanalysen mit Messwiederholung durchgef{\"u}hrt, gefolgt von t-Tests zur weiterf{\"u}hrenden Analyse. Desweiteren wurden die Aufmerksamkeitsreaktionen von nicht-{\"a}ngstlichen und {\"a}ngstlichen Teilnehmern in Kategorien eingeteilt und mittels Chi-Quadrat Analysen verglichen. Zur Analyse des Zusammenhangs zwischen Furchtgeneralisierung und Aufmerksamkeitsprozessen erfolgte eine Regressionsanalyse mit einem GS Mittelwert als abh{\"a}ngiger Variable und der {\"A}ngstlichkeit und den Aufmerk-samkeitsprozessen als Pr{\"a}diktoren. Die Ergebnisse best{\"a}tigten eine solide Furchtkonditionierung anhand des „Screaming Lady"-Paradigmas in einer klinischen Population, dies war erkennbar an h{\"o}heren Ratings f{\"u}r den aversiven Stimulus im Vergleich zum sicheren Stimulus in beiden Gruppen. Grunds{\"a}tzlich h{\"o}here Furchtratings sowie h{\"o}here Ratings der Generalisierungsstimuli im Vergleich zum sicheren Stimulus wiesen auf eine st{\"a}rkere Generalisierung in der Untergruppe mit h{\"o}herem Angst-Trait innerhalb der internalisierenden Probandengruppe hin. Die Analyse der Dotprobe Daten ergab schnellere Reaktionszeiten sowie h{\"a}ufigere Initialsakkaden gegen{\"u}ber furchteinfl{\"o}ßenden Stimuli bei Patienten mit internalisierender St{\"o}rung. Des Weiteren zeigten sehr {\"a}ngstliche Probanden h{\"a}ufiger einen Attentional bias im Chi Quadrat Test als nicht-{\"a}ngstliche Probanden. Dies wies daraufhin, dass sowohl bei Patienten mit internalisierender St{\"o}rung als auch bei sehr {\"a}ngstlichen Probanden ein Attentional bias gegen{\"u}ber furchtrelevanten Stimuli vorliegt. Vor allem bei Kindern mit internalisierender St{\"o}rung sagten die {\"A}ngstlichkeit und ver{\"a}nderte Aufmerksamkeitsprozesse die Auspr{\"a}gung der Furchtgeneralisierung voraus. Somit kann ein Zusammenhang von ver{\"a}nderten Aufmerksamkeitsprozessen und Furchtgeneralisierung vermutet werden.},
  subject      = {Kinderpsychiatrie},
  language  = {de}
}
@phdthesis{EttlingergebHaberstumpf2023,
  author    = {Ettlinger [geb. Haberstumpf], Sophia},
  title     = {Pathological cognitive decline in the elderly participants of the Vogel Study},
  doi       = {10.25972/OPUS-26558},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-265582},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2023},
  abstract  = {Due to the global aging society and the enormous global incidence and prevalence rates that will result in the coming years, Alzheimer's Dementia (AD) represents a growing challenge for the health care system. The pathogenesis, which is unclear in parts, the chronic progression of AD, which often lasts for years, as well as insufficient diagnostic and therapeutic options complicate an adequate psychotherapeutic and medical approach to the disease. To date, AD is also considered an incurable disease. Therefore, it is essential to gain deeper insights into the early detection or even prevention of AD. Consideration of prodromal syndromes such as Mild Cognitive Impairment (MCI) can provide significant evidence about high-risk groups for AD progression and differentiate cognitively "normal" aging individuals from those with pathological cognitive decline. Thus, for example, functional Near-Infrared Spectroscopy (fNIRS) imaging helps identify early neurodegenerative processes. In contrast, potential risk factors and predictors of later-onset clinical symptoms of MCI and AD can most often be revealed and quantified via the use of neuropsychiatric test batteries. The present thesis consists of four studies and aimed to assess and describe the pathological cognitive decline in a sample of elderly study participants (age: ≥ 70 years; N = 604 at baseline) of the longitudinal, observational, and prospective "Vogel Study" from W{\"u}rzburg, Germany, who were primarily healthy at baseline, over two measurement time points approximately 3 years apart, to differentiate between healthy and diseased study participants and to define predictors of MCI/AD and longitudinal study dropout. Studies 1 and 2 differentiated healthy study participants from MCI patients based on the baseline hemodynamic response of the parietal cortex recorded by fNIRS during the processing of a paradigm (here: Angle Discrimination Task [ADT]) for visual-spatial processing performance. Neuronal hypoactivity was found in the MCI patients, with both healthy study participants and MCI patients showing higher superior and right hemispheric activation. MCI patients had more difficulty resolving the paradigm. Thus, no evidence of possible compensatory mechanisms was uncovered in the MCI patients. Study 3 first defined the four latent factors declarative memory, working memory, attention, and visual-spatial processing based on structural equation model (SEM) calculations of the sample using adequate measurement (in-)variant confirmatory factor models from the baseline assessment to the first of a total of two follow-up assessments after approximately 3 years. This allowed a dimensional assessment of pathological cognitive decline versus classificatory-categorical assignment (healthy/diseased) of the sample. In addition, the superiority of the latent factor approach over a composite approach was demonstrated. Next, using a mixed-model approach, predictive analyses were calculated for the prediction of latent factors at first follow-up by baseline risk factors. The sex of study participants proved to be the best predictor of cognitive change in all the cognitive domains, with females performing better than men in the memory domains. Specifically, for declarative memory, older age predicted lower performance regardless of sex. Additional predictive evidence emerged for low serum levels of Brain-Derived Neurotrophic Factor (BDNF) on lower attention performance and higher depression symptoms on lower visual-spatial processing performance. Study 4 further reported baseline predictors of study dropout at first follow-up. Cognitive performance, as defined in Study 3 using the four latent cognitive factors, was a predictor of study dropout for cognitive decline in the domains of declarative memory, attention, and visual-spatial processing. Conspicuous dementia screening on the Mini-Mental Status Examination (MMSE) also predicted dropout. Overall, both the use of fNIRS imaging to detect visual-spatial processing performance in the parietal cortex during applying ADT and the dimensional perspective of the neuropsychiatric test battery in the context of prediction and dropout analyses were found to be suitable for early detection research of MCI and AD. Finally, the results will be interpreted in the overall context and implications, limitations, and perspectives will be discussed.},
  language  = {en}
}
@phdthesis{Seeger2023,
  author    = {Seeger, Fabian Reinhard},
  title     = {Moderators of exposure-based treatment outcome in anxiety disorders: an fMRI approach},
  doi       = {10.25972/OPUS-21435},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-214356},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2023},
  abstract  = {Even though exposure-based cognitive behavioral therapy (CBT) constitutes a first-line treatment for anxiety disorders, a substantial proportion of patients does not respond in a clinically significant manner. The identification of pre-treatment patient characteristics that are associated with treatment outcome might aid in improving response rates. Therefore, the present doctoral thesis aimed at investigating moderators of treatment outcome in anxiety disorders: first, we investigated the neural correlates of comorbidity among primary panic disorder/agoraphobia (PD/AG) and secondary social anxiety disorder (SAD) moderating treatment outcome towards exposure-based CBT. Second, pre-treatment functional resting-state connectivity signatures of treatment response in specific phobia were studied. Within the first study, we compared PD/AG patients with or without secondary SAD regarding their clinical and neurofunctional outcome towards a manualized CBT treatment focusing on PD/AG symptoms. Prior to treatment, PD/AG+SAD compared to PD/AG-SAD patients exhibited a specific neural signature within the temporal lobe, which was attenuated to the level of PD/AG-SAD patients afterwards. CBT was equally effective in both groups. Thus, comorbidity among those two anxiety disorders did not alter treatment outcome substantially. This might be due to the high overlap of shared pathophysiological features within both disorders. In the second study, we assessed pre-treatment functional resting-state connectivity within a sample of spider phobic patients that were treated with massed in virtuo exposure. We found responders already prior to treatment to be characterized by stronger inhibitory frontolimbic connectivity as well as heightened connectivity between the amygdala and regions related to the ventral visual stream. Furthermore, patients demonstrating high within-session extinction exhibited pronounced intrinsic prefrontal connectivity. Our results point to responders exhibiting a brain prepared for the mechanism of action of exposure. Taken together, results highlight the major impact of pre-treatment characteristics on treatment outcome. Both, PD/AG+SAD patients as well as responders within the SpiderVR study exhibited heightened activation or connectivity within the ventral visual pathway and the amygdala. Pronounced visual processing together with enhanced executive control and emotion regulation seem to constitute a fruitful soil for successful exposure. The results provide starting points for personalized treatment approaches in order to improve treatment success in the anxiety disorders. Future studies are needed to investigate the benefit of neuroscientifically informed CBT augmentation strategies such as repetitive transcranial magnetic stimulation.},
  subject      = {Angstst{\"o}rung},
  language  = {en}
}
@phdthesis{Siminski2023,
  author    = {Siminski, Niklas},
  title     = {Temporal predictability of threat: Evaluation of differential involvement of amygdala and BNST, and relevance for therapy response prediction in spider phobia},
  doi       = {10.25972/OPUS-24664},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-246643},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2023},
  abstract  = {Predictability of threat is one of the key modulators of neural activity in fear and anxiety-related threat processes and there is a considerable number of studies focusing on the exact contribution of centromedial amygdala and Bed nucleus of stria terminalis (BNST) in animals as well as in humans. In this research field, some studies already investigated the differential involvement of both areas during temporally predictable and unpredictable threat processes in humans. However, these studies showed several limitations e.g. small sample size, no predictable threat conditions, no separation of anticipation and confrontation processes, which should be addressed in future studies. Furthermore, evidence for group-based inter-individual differences of amygdala and BNST activity during predictable and unpredictable threat processes have not been studied extensively. Several studies suggest a relevant role of the amygdala and BNST activity in phobic processes in patients with specific phobia, but no study so far has investigated the exact contribution of centromedial amygdala (CM) and BNST during temporally predictable and unpredictable threat processes in specific phobia. This thesis consisted of three studies and aimed to evaluate the exact contribution of CM and BNST during temporally predictable and unpredictable threat anticipation and confrontation with the use of an optimized functional magnetic resonance imaging (fMRI) paradigm, which aimed to solve methodological limitations of recent studies. Study 1 used a large sample of healthy participants who were grouped based on NPSR1 genotype, and study 2 and study 3 used a sample of patients with spider phobia. In sum, the results of all three studies indicated, that BNST is more relevant for anticipation processes as compared to the CM. Contrary, during the confrontation phase the CM displays a greater relevance for threat confrontation processes. In recent years, various studies have investigated the extent to which treatment success can be predicted in patients with anxiety disorders based on pre-treatment fMRI activity. Therefore, this was investigated for the first time in study 3 in patients with spider phobia during temporally predictable and unpredictable threat processes. Results indicated that independent of temporal predictability lower anterior cingulate cortex (ACC) activity during threat anticipation and engaged BNST during threat confrontation might be benefitting factors for successful therapy response in spider phobia.},
  subject      = {Amygdala},
  language  = {en}
}
@phdthesis{Breil2023,
  author    = {Breil, Christina},
  title     = {Look at me and I will feel you: eye contact and social understandig},
  doi       = {10.25972/OPUS-27802},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-278021},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2023},
  abstract  = {One of the features that defines humans as extraordinarily social beings is their striking susceptibility to the gaze of others. The research reported in this dissertation was undertaken to advance our understanding of the role of gaze cues in low-level attentional and higher-order cognitive processes. In particular, effects of gaze were examined with regard to three aspects of human cognition: (1) social attention, (2) social interaction and (3) social understanding. Chapter 1 consists of three manuscripts that investigate the boundary conditions of attention capture by direct gaze and how gaze direction is integrated with facial context information. Manuscript 1 and 2 suggest two necessary requirements for attention capture by direct gaze: a meaningful holistic facial context and sharp foveal vision, respectively. Manuscript 3 shows approach/avoidance-congruency effects between gaze direction and emotion expression on attention. Chapter 2 of this dissertation explores the role of gaze in more naturalistic social scenarios. Manuscript 4 demonstrates that gaze behavior during a conversation shapes our perception of another person. Manuscript 5 builds on these findings by showing that these perceptions define our willingness to act in a prosocial way towards our interaction partner. Finally, chapter 3 adopts a broader perspective on social cognition research with a special focus on methodological aspects. Manuscript 6 is a review highlighting the significance of methodological aspects in social cognition research and stressing the importance of sophisticated decisions on task and stimulus materials. Manuscript 7 introduces a new instrument for the assessment of social understanding in adolescents. Initial application in a young sample group indicates that an understanding of another person's mental states is a capacity that is still developing throughout adolescence. Both manuscripts of this final chapter include eye tracking data that suggest a relationship between gaze behavior and social understanding, a finding that further emphasizes the complex and multifaceted nature of social cognition. I conclude from the findings of this dissertation that research can benefit from adopting a broad view in terms of methodological as well as temporal aspects in order to capture human social cognition in its entirety.},
  subject      = {Blick},
  language  = {en}
}
@phdthesis{Peters2023,
  author    = {Peters, Katharina},
  title     = {Biological Substrates of Waiting Impulsivity in Children and Adolescents with and without ADHD},
  doi       = {10.25972/OPUS-24636},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-246368},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2023},
  abstract  = {Focus of the present work were the questions whether and how the concept of waiting impulsivity (WI), defined as the ability to regulate a response in anticipation of reward and measured by the 4-choice serial reaction time task (4-CSRTT), may contribute to our understanding of Attention-Deficit/Hyperactivity Disorder (ADHD) and its neurobiological underpinnings. To address this topic, two studies were conducted: in a first study, the relationship be-tween 4-CSRTT behavioral measures, neural correlates and ADHD symptom domains, i.e. inattention (IA) and hyperactivity/impulsivity (H/I) was explored in a pooled sample of 90 children and adolescents with (n=44) and without (n=46) ADHD diagnosis. As ex-pected, IA was associated with dorsolateral prefrontal brain regions linked with executive functions and attentional control, which was evident on the structural and the functional level. Higher levels of both IA and H/I covaried with decreased activity in the right ven-trolateral prefrontal cortex (PFC), a central structure for response inhibition. Moderation analyses revealed that H/I-related decreased activation in this region did not map linearly on difficulties on the behavioral level: brain activation was a significant predictor of task accuracy only, when H/I symptoms were low/absent but not for clinically relevant ADHD symptoms. Further, H/I was implicated in dysfunctional top-down control of reward eval-uation. Both symptom domains correlated positively with hippocampus (HC) activity in anticipation of reward. In addition, for high H/I symptoms, greater activation in the HC was found to correlate with higher motivation on the behavioral level, indicating that rein-forcement-learning and/or contingency awareness may contribute to altered reward pro-cessing in ADHD patients. In a second study, the possible serotonergic modulation of WI and the ADHD-WI relation-ship was addressed in a sub-sample comprising 86 children and adolescents of study I. The effects of a functional variant in the gene coding for the rate-limiting enzyme in the synthesis of brain serotonin on behavior and structure or function of the WI-network was investigated. Moderation analyses revealed that on the behavioral level, a negative corre-lation between accuracy and IA was found only in GG-homozygotes, whereas no signifi-cant relationship emerged for carriers of the T-allele. This is in line with previous reports of differential effects of serotonergic modulation on attentional performance depending on the presence of ADHD symptoms. A trend-wise interaction effect of genotype and IA for regional volume of the right middle frontal gyrus was interpreted as a hint towards an involvement of the PFC in this relationship, although a more complex mechanism includ-ing developmental effects can be assumed. In addition, interaction effects of genotype and IA were found for brain activation in the amygdala (AMY) und HC during perfor-mance of the 4-CSRTT, while another interaction was found for H/I symptoms and geno-type for right AMY volume. These findings indicate a serotonergic modulation of coding of the emotional value of reward during performance of the 4-CSRTT that varies de-pending on the extent of psychopathology-associated traits. Taken together, it was shown that the 4-CSRTT taps distinct domains of impulsivity with relevance to ADHD symptomatology: (proactive) response inhibition difficulties in relation with anticipation of reward. Furthermore, the two symptom domains, IA and H/I, contrib-ute differently to WI, which emphasizes the need to distinguish both in the research of ADHD. The results of study II emphasized the relevance of serotonergic transmission especially for attentional control and emotional processing. Although the present findings need replication and further refinement in more homogenous age groups, the use of the 4-CSRTT with a dimensional approach is a very promising strategy, which will hopefully extend our understanding of impulsivity-related mental disorders in the future.},
  subject      = {Aufmerksamkeitsdefizit-Syndrom},
  language  = {en}
}