@phdthesis{Chiossi2013, author = {Chiossi, Clarissa}, title = {Neuronale Grundlagen der Pers{\"o}nlichkeit nach Gray: Ein Vergleich von Ego-Shooter-Spielern und -Nicht-Spielern}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-93090}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2013}, abstract = {Hintergrund: Das Spielen von Computerspielen ist ein viel diskutiertes Thema. Auf der Suche nach Auswirkungen des Spielens lassen sich einige Studien finden, die Ver{\"a}nderungen im Erleben und Verhalten zeigen [6-8]. Bei der Frage nach der Ursache hierf{\"u}r, m{\"u}ssen Aspekte wie Pers{\"o}nlichkeit, Hirnphysiologie, neuronale Grundlagen und Genetik untersucht und diskutiert werden. Der bekannte Pers{\"o}nlichkeitsforscher J. Alan Gray beschreibt in seiner Reinforcement Sensitivity Theory (RST) drei verschiedene Hirnsysteme, die das Ann{\"a}herungs- und Vermeidungsverhalten regulieren. Eines dieser Systeme, das Behavioral Inhibition System (BIS) wird ganz besonders h{\"a}ufig beim Spielen von sogenannten Ego-Shooter Spielen aktiviert. Ziel: Ziel der Untersuchung war es, herauszufinden, ob das Spielen dieser Computerspiele einen Trainingseffekt auf neurophysiologische Grundlagen der Pers{\"o}nlichkeit, genauer des BIS nach Gray, hat. Wenn es einen erlernten Effekt gibt, m{\"u}sste ein signifikanter Unterschied zwischen den BIS scores der Spieler und Nicht-Spieler erkennbar sein. Sollte es keinen signifikanten Unterschied geben, kann es dennoch sein, dass sich das neuronale Substrat (also die physiologische Grundlage) des BIS durch das Training ver{\"a}ndert, auch wenn dies dann nicht zu einem anderem Verhalten f{\"u}hrt. Methoden: Es wurden die Ergebnisse von jeweils 17 Ego-Shooter-Spielern und Nicht-Spielern aus dem Fragebogen SPSRQ bez{\"u}glich Unterschieden in den Mittelwerten der BIS scores mithilfe eines t-Tests miteinander verglichen. Außerdem wurde von allen Probanden fMRT - Datenmaterial gewonnen und zun{\"a}chst eine zweifaktorielle ANOVA durchgef{\"u}hrt: die Faktoren waren Spieler (Ja/Nein) und BIS score und gemessen wurde die neuronale Aktivit{\"a}t in Amygdala und Hippocampus im resting state. Um den bekannten St{\"o}rfaktor Genetik miteinzubeziehen, erfolgte anschließend eine dreifaktorielle ANOVA mit der Kovariate TPH2. F{\"u}r die Bestimmung dieser Kovariate wurde jedem Probanden ein R{\"o}hrchen Blut entnommen und eine Genotypisierung durchgef{\"u}hrt. Ergebnisse: Der Vergleich der BIS scores mittels t-Test liefert keinen signifikanten Unterschied zwischen Spielern und Nicht-Spielern. In der zweifaktoriellen Varianzanalyse zeigen sich signifikante Unterschiede und eine unterschiedliche Richtung der Korrelation. W{\"a}hrend die Korrelation von neuronaler Aktivit{\"a}t und BIS score bei den Spielern positiv ist, ist sie bei den Nicht-Spielern negativ. Der Unterschied verliert in der dreifaktoriellen ANOVA mit der Kovariate TPH2 seine Signifikanz. Schlussfolgerung: Die Ergebnisse der Arbeit f{\"u}hren zu der entscheidenden Frage, wie unterschiedliche neuronale Aktivit{\"a}ten entstehen. Zwei sehr kontroverse Ans{\"a}tze stehen sich dabei gegen{\"u}ber: 1. Der Genotyp hat einen Einfluss auf die neuronale Plastizit{\"a}t w{\"a}hrend der Entwicklung. Die vorliegende Arbeit, wie auch fr{\"u}here Studien -wie die von Hahn et al. [58] - geben Hinweise darauf, dass der Genotyp diesen Einfluss besitzt. Die Tendenz, die bei der Genotypisierung zu sehen ist, l{\"a}sst die Spekulation zu, dass Personen mit einem bestimmten Genotyp eher zu Spielern werden, als Personen mit einer anderen Auspr{\"a}gung. Um diese Frage zu kl{\"a}ren, sind Untersuchungen mit einem gr{\"o}ßeren Stichprobenumfang notwendig. 2. Die Unterschiede sind das Ergebnis eines sogenannten Trainingseffektes, entstehen also durch Einfluss von außen und h{\"a}ngen ab von den jeweiligen Erlebnissen, die im Laufe eines Lebens gemacht werden. Trotz der Ergebnisse, die den starken Einfluss des Genotyps aufzeigen, bleibt eine Restwahrscheinlichkeit f{\"u}r den Trainingseffekt und der Anreiz f{\"u}r weitere Studien mit dieser Fragestellung.}, subject = {Pers{\"o}nlichkeitstheorie}, language = {de} } @phdthesis{Slyschak2022, author = {Slyschak, Anna}, title = {Fear conditioning, its generalization and extinction in children and adolescents under consideration of trait anxiety and anxiety sensitivity}, doi = {10.25972/OPUS-26780}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-267806}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2022}, abstract = {The propounded thesis investigated fear learning including fear conditioning, its generalization as well as its extinction in 133 healthy children and adolescents aged 8 to 17 years. The main goal was to analyze these processes also in the course of childhood and adolescence due to far less research in this age span compared to adults. Of note, childhood is the typical period for the onset of anxiety disorders. To achieve this, an aversive discriminative fear conditioning, generalization and extinction paradigm, which based on the "screaming lady paradigm" from Lau et al. (2008) and was adapted by Schiele \& Reinhard et al. (2016), was applied. All probands traversed the pre-acquisition (4 x CS-, 4 x CS+, no US), the acquisition (12 x CS-, 12 x CS+, reinforcement rate: 83\%), the generalization (12 x CS-, 12 x GS4, 12 x GS3, 12 x GS2, 12 x GS1, 12 x CS+, reinforcement rate: 50\%) and the extinction (18 x CS-, 18 x CS+, no US). The generalization stimuli, i.e. GS1-GS4, were built out of CS- and CS+ in different mixtures on a percentage basis in steps of 20\% from CS- to CS+. Pictures of faces of two actresses with a neutral expression were used for the discriminative conditioning, whereby the CS+ was paired with a 95-dB loud female scream at the same time together with a fearful facial expression (US). CS- and GS1-GS4 were never followed by the US. Subjective ratings (arousal, valence and US expectancy) were collected and further the psychophysiological measure of the skin conductance response (SCR). The hypotheses were 1) that underage probands show a negative correlation between age and overgeneralization and 2) that anxiety is positively correlated with overgeneralization in the same sample. ANOVAs with repeated measures were conducted for all four dependent variables with phase (pre-acquisition phase, 1. + 2. acquisition phase, 1. + 2. generalization phase, 1. - 3. extinction phase) and stimulus type (CS-, CS+, GS1-GS4) as within-subject factors. For the analyses of the modulatory effects of age and anxiety in additional separate ANCOVAs were conducted including a) age, b) the STAIC score for trait anxiety and c) the CASI score for anxiety sensitivity as covariates. Sex was always included as covariate of no interest. On the one hand, findings indicated that the general extent of the reactions (arousal, valence and US expectancy ratings and the SCR) decreased with growing age, i.e. the older the probands the lower their reactions towards the stimuli regardless of the type of dependent variable. On the other hand, ratings of US expectancy, i.e. the likelihood that a stimulus is followed by a US (here: female scream coupled with a fearful facial expression), showed better discrimination skills the older the probands were, resulting in a smaller overgeneralization within older probands. It must be emphasized very clearly that no causality can be derived. Thus, it was only an association revealed between 15 age and generalization of conditioned fear, which is negative. Furthermore, no obvious impact of trait anxiety could be detected on the different processes of fear learning. Especially, no overgeneralization was expressed by the probands linked to higher trait anxiety. In contrast to trait anxiety, for anxiety sensitivity there was an association between its extent and the level of fear reactions. This could be described best with a kind of parallel shifts: the higher the anxiety sensitivity, the stronger the fear reactions. Likewise, for anxiety sensitivity no overgeneralization due to a stronger extent of anxiety sensitivity could be observed. Longitudinal follow-up examinations and, furthermore, neurobiological investigations are needed for replication purposes and purposes of gaining more supporting or opposing insights, but also for the profound exploration of the impact of hormonal changes during puberty and of the maturation processes of different brain structures. Finally, the question whether enhanced generalization of conditioned fear facilitates the development of anxiety disorders or vice versa remains unsolved yet.}, subject = {Furcht}, language = {en} } @phdthesis{Holweck2022, author = {Holweck, Julia}, title = {Putative Biomarker neuropsychiatrischer Entwicklungskomorbidit{\"a}ten beim Deletionssyndrom 22q11.2}, doi = {10.25972/OPUS-29291}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-292915}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2022}, abstract = {Vom Deletionssyndrom 22q11.2 Betroffene sind einem {\"u}berdurchschnittlich hohen Risiko ausgesetzt im Entwicklungsverlauf psychisch zu erkranken. H{\"a}ufige St{\"o}rungsbilder sind unter anderem ADHS, Angsterkrankungen, affektive St{\"o}rungen, Erkrankungen aus dem schizophrenen Formenkreis und Morbus Parkinson. Ziel der Studie war es, ph{\"a}notypische Auff{\"a}lligkeiten beim DS22q11 zu identifizieren, die dabei helfen k{\"o}nnten, Hochrisikogruppen innerhalb des Syndroms fr{\"u}hzeitig identifizieren zu k{\"o}nnen und in Form von Biomarkern messbar sind. Hierzu wurden die bereits in Forschung und teilweise auch in der Klinik etablierten Verfahren der transkraniellen Sonographie und der standardisierten Riechtestung eingesetzt.}, subject = {Mikrodeletionssyndrom 22q11}, language = {de} } @phdthesis{vonSchoenfeld2022, author = {von Sch{\"o}nfeld, Cornelia}, title = {Universal prevention of nonsuicidal self-injury for children and adolescents - A systematic review -}, doi = {10.25972/OPUS-28702}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-287020}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2022}, abstract = {In a synopsis of the current state of research regarding NSSI, there are two key findings of this thesis: Firstly, there is a severe scarcity of studies and currently no evidence base for effective universal prevention of NSSI in youth. Secondly, not only the number but also quality of those few studies found was considered too low to draw wide-ranging conclusions and no meta-analysis could be conducted. This conclusion based - among other factors listed in chapter six - on the application of the EPHPP quality assessment tool (Evans, Lasen et al. 2015), which revealed distinct deficiencies and a weak overall study quality for all seven studies. Even if the high prevalence of NSSI among adolescents and the importance of this field of research is increasingly emphasized in contemporary literature (Muehlenkamp, Walsh et al. 2010, Wasserman, Carli et al. 2010, Brunner, Kaess et al. 2014, Plener, Schumacher et al. 2015), the shortage of concrete programs addressing the issue is manifest. The potential to tackle NSSI via prevention is underlined in view of the fact that many recent studies prove the high potential of primary prevention regarding NSSI incidences (Evans, Hawton et al. 2005, Fortune, Sinclair et al. 2008). From the studies included for this review, it can be concluded that most interventions show positive effects in raising awareness, knowledge, understanding of risk factors and help-seeking attitudes among school staff or students, particularly when starting with low knowledge at baseline (Robinson, Gook et al. 2008). Yet, most studies focus on training of gatekeepers and only two programmes address students directly and primarily measure actual NSSI behaviour. This finding highlights the importance of more investigation into concrete NSSI measurement targeting mainly the group of youth. There is a severe lack of literature on primary prevention with suitable contexts and target groups, while reviews on secondary targeted prevention deliver much more potential in the quantity of research (Kothgassner, Robinson et al. 2020, Kothgassner, Goreis et al. 2021). Until that changes, secondary prevention approaches of NSSI should be relied upon first. Looking into the future, several considerations may help advance universal approaches to NSSI. Regarding study planning, it is crucial for future research to pursue a thorough background research, examine the feasibility of interventions, and evaluate the appropriateness of study samples chosen. Moreover, research groups are expected to ensure a close observation of participants in cases of adverse events, in order to offer support, but also detect potential deficiencies in the study organisation. Additionally - in accordance with other research in this field (Plener, Brunner et al. 2010) - findings of this review highlight the necessity to expand fundamental research on functions of NSSI and its (neurobiological) mechanism of formation in order to enhance the knowledge of correlations and improve effective preventive approaches. As psychoeducational methods have shown risks of iatrogenic effects (e.g. in patients with eating disorders) (Stice, 2007 \#10063), it might be worthwhile to focus on improving emotion regulation in order to strengthen protective factors and improve adolescents' management of their everyday lives rather than on merely mitigating possible risk factors. Regarding intervention costs, it appears indispensable to include more cost calculations in the study planning of future research. In contrast to therapeutic interventions of NSSI, which are usually conducted in an in-patient setting and entail high measurable expenses as compared to preventive interventions, preventive approaches may in case of success result in a reduction of clinical presentation (O'Connell, Boat et al. 2009). A promising outlook is entailed by study protocol presenting a skills-based universal prevention program of NSSI "DUDE", a cluster randomized controlled trial scheduled for 16 German schools with a total of 3.200 adolescents (Buerger, Emser et al. 2022). The program is tailored to decrease the incidence of NSSI and avert potential and associated long-term consequences like suicidality among adolescents. It is aimed to provide easy access for adolescents due to its implementation during lesson time at school and is declared cost-effective. Furthermore, DUDE is a promising approach to effective NSSI prevention, as it is intended to improve mental health through the pathway of emotion regulation. It remains to await the implementation of the protocol, which is currently delayed due to the SARS-CoV-19 pandemic. In sum, initial research is promising and suggests that the approach to tackle NSSI via prevention is meaningful. Yet, high-quality studies on the development and evaluation of universal NSSI prevention in adolescents are urgently needed.}, language = {en} } @phdthesis{Lueffe2023, author = {L{\"u}ffe, Teresa Magdalena}, title = {Behavioral and pharmacological validation of genetic zebrafish models for ADHD}, doi = {10.25972/OPUS-25716}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-257168}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2023}, abstract = {Attention-deficit/hyperactivity disorder (ADHD) is the most prevalent neurodevelopmental disorder described in psychiatry today. ADHD arises during early childhood and is characterized by an age-inappropriate level of inattention, hyperactivity, impulsivity, and partially emotional dysregulation. Besides, substantial psychiatric comorbidity further broadens the symptomatic spectrum. Despite advances in ADHD research by genetic- and imaging studies, the etiopathogenesis of ADHD remains largely unclear. Twin studies suggest a heritability of 70-80 \% that, based on genome-wide investigations, is assumed to be polygenic and a mixed composite of small and large, common and rare genetic variants. In recent years the number of genetic risk candidates is continuously increased. However, for most, a biological link to neuropathology and symptomatology of the patient is still missing. Uncovering this link is vital for a better understanding of the disorder, the identification of new treatment targets, and therefore the development of a more targeted and possibly personalized therapy. The present thesis addresses the issue for the ADHD risk candidates GRM8, FOXP2, and GAD1. By establishing loss of function zebrafish models, using CRISPR/Cas9 derived mutagenesis and antisense oligonucleotides, and studying them for morphological, functional, and behavioral alterations, it provides novel insights into the candidate's contribution to neuropathology and ADHD associated phenotypes. Using locomotor activity as behavioral read-out, the present work identified a genetic and functional implication of Grm8a, Grm8b, Foxp2, and Gad1b in ADHD associated hyperactivity. Further, it provides substantial evidence that the function of Grm8a, Grm8b, Foxp2, and Gad1b in activity regulation involves GABAergic signaling. Preliminary indications suggest that the three candidates interfere with GABAergic signaling in the ventral forebrain/striatum. However, according to present and previous data, via different biological mechanisms such as GABA synthesis, transmitter release regulation, synapse formation and/or transcriptional regulation of synaptic components. Intriguingly, this work further demonstrates that the activity regulating circuit, affected upon Foxp2 and Gad1b loss of function, is involved in the therapeutic effect mechanism of methylphenidate. Altogether, the present thesis identified altered GABAergic signaling in activity regulating circuits in, presumably, the ventral forebrain as neuropathological underpinning of ADHD associated hyperactivity. Further, it demonstrates altered GABAergic signaling as mechanistic link between the genetic disruption of Grm8a, Grm8b, Foxp2, and Gad1b and ADHD symptomatology like hyperactivity. Thus, this thesis highlights GABAergic signaling in activity regulating circuits and, in this context, Grm8a, Grm8b, Foxp2, and Gad1b as exciting targets for future investigations on ADHD etiopathogenesis and the development of novel therapeutic interventions for ADHD related hyperactivity. Additionally, thigmotaxis measurements suggest Grm8a, Grm8b, and Gad1b as interesting candidates for prospective studies on comorbid anxiety in ADHD. Furthermore, expression analysis in foxp2 mutants demonstrates Foxp2 as regulator of ADHD associated gene sets and neurodevelopmental disorder (NDD) overarching genetic and functional networks with possible implications for ADHD polygenicity and comorbidity. Finally, with the characterization of gene expression patterns and the generation and validation of genetic zebrafish models for Grm8a, Grm8b, Foxp2, and Gad1b, the present thesis laid the groundwork for future research efforts, for instance, the identification of the functional circuit(s) and biological mechanism(s) by which Grm8a, Grm8b, Foxp2, and Gad1b loss of function interfere with GABAergic signaling and ultimately induce hyperactivity.}, language = {en} } @phdthesis{Akhrif2023, author = {Akhrif, Atae}, title = {The BOLD Signal is more than a Brain Activation Index}, doi = {10.25972/OPUS-32287}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-322879}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2023}, abstract = {In the recent years, translational studies comparing imaging data of animals and humans have gained increasing scientific interests with crucial findings stemming from both, human and animal work. In order to harmonize statistical analyses of data from different species and to optimize the transfer of knowledge between them, shared data acquisition protocols and combined statistical approaches have to be identified. Following this idea, methods of data analysis, which have until now mainly been used to model neural responses of electrophysiological recordings from rodent data, were applied on human hemodynamic responses (i.e. Blood-Oxygen-Level- Dependent BOLD signal) as measured via functional magnetic resonance imaging (fMRI). At the example of two attention and impulsivity networks, timing dynamics and amplitude of the fMRI signal were determined (study 1). Study 2 described the same parameters frequency-specifically, and in study 3, the complexity of neural processing was quantified in terms of fractality. Determined parameters were compared with regard to the subjects' task performance / impulsivity to validate findings with regard to reports of the current scientific debate. In a general discussion, overlapping as well as additional information of methodological approaches were discussed with regard to its potential for biomarkers in the context of neuropsychiatric disorders.}, subject = {funktionelle Kernspintomographie}, language = {en} } @phdthesis{HeingebGienk2021, author = {Hein [geb. Gienk], Stella Anneliese}, title = {Die Auswirkung der ADHS Erkrankung auf die Bearbeitung einer kognitiven „Set Shifting" Aufgabe}, doi = {10.25972/OPUS-23750}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-237504}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2021}, abstract = {Das Ziel der vorliegenden Arbeit war die Untersuchung der Impulsivit{\"a}t bei adulten Patienten mit ADHS. Es wurden 19 adulte Patienten mit ADHS und 20 gesunde Kontrollprobanden, die nach Alter, Geschlecht und Schulabschluss vergleichbar waren, untersucht. Wir nutzten ein kognitives Set Shifting Paradigma und erfassten die Verhaltensdaten (Reaktionszeit und Fehler) sowie hirnphysiologische {\"A}nderungen mittels funktioneller Nahinfrarotspektroskopie (fNIRS). Als „Region of Interest" (ROI) legten wir den dorsolateralen pr{\"a}frontalen Kortex (dlPFC) fest. Zus{\"a}tzlich erfolgte eine Selbsterfassung der Impulsivit{\"a}t mittels BIS 11, SPSRQ und UPPS Fragebogen. Auf der Verhaltensebene zeigten die Patienten mit ADHS im Vergleich zu den gesunden Kontrollprobanden eine verl{\"a}ngerte Reaktionszeit. Die Bearbeitung einer Shift Aufgabe f{\"u}hrte bei beiden Probandengruppen zu einer verl{\"a}ngerten Reaktionszeit sowie einer erh{\"o}hten Fehlerzahl im Verh{\"a}ltnis zu einer No Shift Aufgabe. In der Erhebung der funktionellen Daten konnten wir einen signifikanten Unterschied zwischen den Gruppen im Bereich der ROI feststellen. Die gesunden Kontrollprobanden wiesen eine erh{\"o}hte Hirnaktivit{\"a}t im dlPFC auf. In den Frageb{\"o}gen zur Selbsterfassung der Impulsivit{\"a}t erreichten die Patienten in den meisten Unterskalen Werte, die mit erh{\"o}hter Impulsivit{\"a}t einhergehen.}, subject = {Aufmerksamkeitsdefizit-Syndrom}, language = {de} } @phdthesis{Daub2023, author = {Daub, Jonas}, title = {Der Einfluss von Alter und {\"A}ngstlichkeit auf die Furchtgeneralisierung und die Aufmerksamkeitslenkung bei gesunden Kindern und Jugendlichen}, doi = {10.25972/OPUS-30010}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-300100}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2023}, abstract = {Mittels einer klinischen Studie wurden die Furchtgeneralisierung und Aufmerksamkeitslenkung von 44 gesunden Kindern und Jugendlichen im Alter von 9-17 Jahren untersucht. Eine {\"U}bergeneralisierung konditionierter Furcht sowie ver{\"a}nderte Aufmerksamkeitsprozesse werden in zahlreichen Arbeiten mit der Entstehung und Aufrechterhaltung von Angsterkrankungen in Verbindung gebracht. Der Hauptteil der Forschung beschr{\"a}nkte sich bislang auf die Untersuchung von erwachsenen Probanden. Da Angsterkrankungen jedoch h{\"a}ufig bereits im Kindes- und Jugendalter entstehen und sich in der Erforschung psychiatrischer Erkrankungen zunehmend eine dimensionale Betrachtungsweise durchsetzt, bestand das Ziel der Studie darin, etwaige Alterseffekte und den Einfluss der {\"A}ngstlichkeit auf die genannten Ph{\"a}nomene bei gesunden Probanden zu untersuchen. Dar{\"u}ber hinaus wurde ein potentiell pr{\"a}ventiver Ansatz erforscht. Im Ergebnis zeigten sich in den Gruppenvergleichen keine relevanten Differenzen. Interessanterweise deutete sich in der Gruppe der {\"a}lteren Probanden entgegen der Erwartung eine verst{\"a}rkte Furchtgeneralisierung an, die wom{\"o}glich mit einer ver{\"a}nderten Beziehung zu Furcht und Risiko in der Adoleszenz zusammenh{\"a}ngt. Aus den Befunden ergibt sich die Notwendigkeit weiterer, prospektiver Arbeiten, um unser Verst{\"a}ndnis der {\"A}tiologie von Angsterkrankungen zu verbessern. Weiterhin ist noch offen, inwiefern es sich bei der {\"U}bergeneralisierung und einer ver{\"a}nderten Aufmerksamkeitslenkung um Risikofaktoren f{\"u}r die Entwicklung von Angsterkrankungen oder vielmehr um Epiph{\"a}nomene handelt, die erst mit Ausbruch der Erkrankung auftreten. Der Einsatz von Methoden der virtuellen Realit{\"a}t erscheint besonders geeignet, diese Prozesse zuk{\"u}nftig noch besser zu erforschen.}, subject = {Angst}, language = {de} } @phdthesis{Reuter2020, author = {Reuter, Isabel}, title = {Development and function of monoaminergic systems in the brain of zebrafish}, doi = {10.25972/OPUS-20408}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-204089}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2020}, abstract = {This thesis explores the development of monoaminergic systems in the central nervous system (CNS) of zebrafish. The serotonergic cells of the hypothalamus pose the main focus of the present work. Most vertebrates except for mammals possess serotonin (5-HT) synthesising cells in more than one region of the CNS. In zebrafish such regions are, e.g. the hypothalamus, the raphe nuclei and the spinal cord. Serotonin functions as a neurotransmitter and neuromodulator in the CNS. Presumably due to its neuromodulatory tasks hypothalamic serotonergic cells are in contact with the cerebrospinal fluid (CSF), which expands the field of potential serotonergic targets tremendously. This highlights that serotonergic CSF-contacting (CSF-c) cells are vital for the execution of many functions and behaviours. Further, the hypothalamic serotonergic clusters constitute the largest population of serotonergic cells in the CNS of zebrafish. Together, these facts emphasise the need to understand the development and function of serotonergic CSF-c cells in the hypothalamus. Few studies have dealt with this subject, hence, information about the development of these cells is scarce. The zinc-finger transcription factor fezf2, and Fibroblast growth factor (Fgf)-signalling via the ETS-domain transcription factor etv5b are known to regulate serotonergic cell development in the hypothalamus (Bosco et al., 2013; Rink and Guo, 2004). However, the main Fgf ligand responsible for this mediation has not been determined prior to this work. The present thesis identifies Fgf3 as a crucial Fgf ligand. To achieve this result three independent strategies to impair Fgf3 activity have been applied to zebrafish embryos: the fgf3t24152 mutant, an fgf3 morpholino-based knock-down and the CRISPR/Cas9 technique. The investigations show that Fgf3 regulates the development of monoaminergic CSF-c cells in the hypothalamus. Additionally, Fgf3 impacts on cells expressing the peptide hormone arginine vasopressin (avp). Most interestingly, the requirement for Fgf3 by these cells follows a caudo-rostral gradient with a higher dependence on Fgf3 by caudal cells. This also seems to be the case for dopaminergic CSF-c cells in the hypothalamus (Koch et al., 2014). Moreover, etv5b a downstream target of Fgf-signalling is demonstrated to be under the control of Fgf3. With regard to serotonergic CSF-c cell development, it is shown that fgf3 is expressed several hours before tph1a and 5-HT (Bellipanni et al., 2002; Bosco et al., 2013). Together with the result that the hypothalamus is already smaller before mature serotonergic CSF-c cells appear, this argues for an early impact of Fgf3 on serotonergic specification. This hypothesis is supported by several findings in this study: the universal decrease of proliferating cells in the hypothalamus and simultaneous increase of cell death after fgf3 impairment. Complementary cell fate experiments confirm that proliferating serotonergic progenitors need Fgf3 to commit serotonergic specification. Further, these results corroborate findings of an earlier study stating that hypothalamic serotonergic progenitors require Fgf-signalling via etv5b to maintain the progenitor pool (Bosco et al., 2013). Additionally, the transcriptome of the hypothalamus has been analysed and 13 previously overlooked transcripts of Fgf ligands are expressed at developmental stages. The transcriptome analysis provides evidence for a self-compensatory mechanism of fgf3 since expression of fgf3 is upregulated as a consequence of its own impairment. Moreover, the Fgf-signalling pathway appears to be mildly affected by fgf3 manipulation. Together, Fgf-signalling and especially Fgf3 are established to be of critical importance during hypothalamic development with effects on serotonergic, dopaminergic CSF-c and avp expressing cells. Furthermore, this thesis provides two strategies to impair the tph1a gene. Both strategies will facilitate investigations regarding the function of hypothalamic serotonergic CSF-c cells. Finally, the presented findings in this study provide insights into the emergence of the posterior recess region of the hypothalamus, thereby, contributing to the understanding of the evolution of the vertebrate hypothalamus.}, subject = {Hypothalamus}, language = {en} } @phdthesis{Kneer2022, author = {Kneer, Katharina Johanna}, title = {The association of three anxiety dimensions in children and adolescents: their influence on the brain and malleability by a prevention program}, doi = {10.25972/OPUS-25746}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-257468}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2022}, abstract = {Anxiety disorders are the most prevalent group of neuropsychiatric disorders and go along with high personal suffering. They often arise during childhood and show a progression across the life span, thus making this age a specific vulnerable period during development. Still most research about these disorders is done in adults. In light of this, it seems of utmost importance to identify predictive factors of anxiety disorders in children and adolescents. Temperament or personality traits have been proclaimed as risk markers for the development of subsequent anxiety disorders, but their exact interplay is not clear. In this dissertation an effort is made to contribute to the understanding of how risk markers of early temperamental traits, in this case Trait Anxiety, Anxiety Sensitivity and Separation Anxiety are interplaying. While Trait Anxiety is regarded as a more general tendency to react anxiously to threatening situations or stimuli (Unnewehr, Joormann, Schneider, \& Margraf, 1992), Anxiety Sensitivity is the tendency to react with fear to one's own anxious sensations (Allan et al., 2014; S. Reiss, Peterson, Gursky, \& McNally, 1986), and Separation Anxiety is referring to the extent to which the child is avoiding certain situations because of the fear of being separated from primary care givers (In-Albon \& Schneider, 2011). In addition, it will be addressed how these measurements are associated with negative life events, as well as brain functioning and if they are malleable by a prevention program in children and adolescents. In study 1 the aim was to extend the knowledge about the interrelations of this anxiety dimensions and negative life events. Results indicated positive correlations of all three anxiety traits as well as with negative life events. Thus, a close connection of all three anxiety measures as well as with negative life events could be indicated. The closest association was found between Anxiety Sensitivity and Trait Anxiety and between Separation Anxiety and Anxiety Sensitivity. Furthermore, negative life events functioned as mediator between Anxiety Sensitivity and Trait Anxiety, indicating that a part of the association was explained by negative life events. In study 2 we extended the findings from study 1 with neurobiological parameters and examined the influence of anxiety traits on emotional brain activation by administering the "emotional face matching task". This task activated bilateral prefrontal regions as well as both hippocampi and the right amygdala. Further analyses indicated dimension-specific brain activations: Trait Anxiety was associated with a hyperactivation of the left inferior frontal gyrus (IFG) and Separation Anxiety with a lower activation bilaterally in the IFG and the right middle frontal gyrus (MFG). Furthermore, the association between Separation Anxiety and Anxiety Sensitivity was moderated by bi-hemispheric Separation-Anxiety-related IFG activation. Thus, we could identify distinct brain activation patterns for the anxiety dimensions (Trait Anxiety and Separation Anxiety) and their associations (Separation Anxiety and Anxiety Sensitivity). The aim of study 3 was to probe the selective malleability of the anxiety dimensions via a prevention program in an at-risk population. We could identify a reduction of all three anxiety traits from pre- to post-prevention-assessment and that this effect was significant in Anxiety Sensitivity and Trait Anxiety scores. Furthermore, we found that pre-intervention Separation Anxiety and Anxiety Sensitivity post-intervention were associated. In addition, pre-interventive scores were correlated with the intervention-induced change within the measure (i.e., the higher the score before the intervention the higher the prevention-induced change) and pre-intervention Anxiety Sensitivity correlated with the change in Separation Anxiety scores. All relations, seemed to be direct, as mediation/moderation analyses with negative life events did not reveal any significant effect. These results are very promising, because research about anxiety prevention in children and adolescents is still rare and our results are indicating that cognitive-behavioural-therapy based prevention is gilding significant results in an indicated sample even when samples sizes are small like in our study. In sum the present findings hint towards distinct mechanisms underlying the three different anxiety dimensions on a phenomenological and neurobiological level, though they are highly overlapping (Higa-McMillan, Francis, Rith-Najarian, \& Chorpita, 2016; Taylor, 1998). Furthermore, the closest associations were found between Anxiety Sensitivity and Trait Anxiety, as well as between Separation Anxiety and Anxiety Sensitivity. Specifically, we were able to find a neuronal manifestation of the association between Separation Anxiety and Anxiety Sensitivity (Separation Anxiety-specific IFG activation) and a predictive potential on prevention influence. The results of these studies lead to a better understanding of the etiology of anxiety disorders and the interplay between different anxiety-related temperamental traits and could lead to further valuable knowledge about the intervention as well as further prevention strategies.}, subject = {Pr{\"a}vention}, language = {en} }