@phdthesis{SchelpgebTheis2023,
  author    = {Schelp [geb. Theis], Leonie},
  title     = {Zielorientierung am Arbeitsplatz - Ans{\"a}tze f{\"u}r die Mitarbeiterentwicklung},
  doi       = {10.25972/OPUS-20160},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-201602},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2023},
  abstract  = {Die aktuellen Ver{\"a}nderungen der Arbeitswelt erfordern eine stetige Anpassung an immer neue Herausforderungen seitens der Arbeitgeber und Arbeitnehmer. Lebenslanges Lernen und damit eine kontinuierliche Weiterbildung der Mitarbeiter ist essentiell f{\"u}r Unternehmen, um auf dem schnelllebigen Arbeitsmarkt wettbewerbsf{\"a}hig zu sein. Die Bereitschaft und die Motivation von Menschen, dazuzulernen, ist jedoch sehr unterschiedlich. Eine m{\"o}gliche Erkl{\"a}rung daf{\"u}r liefert die dispositionelle Zielorientierung, welche der Achievement-Goal-Theorie entstammt. Das Konstrukt beschreibt, ob Menschen eine individuelle Pr{\"a}ferenz f{\"u}r Lernziele (z.B. Kompetenzzuwachs) oder Leistungsziele (z.B. gute Beurteilungen bekommen oder schlechte Beurteilungen vermeiden) haben. Neben den Pers{\"o}nlichkeitsaspekten konzentriert sich die Forschung im Rahmen der Achievement-Goal-Theorie auch auf den Einfluss der Umgebung auf Lern- und Leistungsprozesse. Die sogenannte arbeitsplatzbezogene Zielorientierung beschreibt die wahrgenommene Zielstruktur der Arbeitsumgebung und stellt das situationsbedingte Gegenst{\"u}ck der Dispositionen dar. Zahlreiche Befunde aus dem Bereich der p{\"a}dagogischen Psychologie zu Zielstrukturen der Umgebung zeigen einen Einfluss auf beispielsweise Lernerfolg, Motivation, Selbstregulationsprozesse oder Leistung. Zielstrukturen im Arbeitskontext stellen hingegen ein bisher wenig beachtetes Konstrukt dar. Ausgehend von den aktuellen Befunden zu Zielstrukturen, k{\"o}nnte die arbeitsplatzbezogene Zielorientierung jedoch einen wichtigen Beitrag leisten, wenn es um die Frage geht, wie Mitarbeiter unterst{\"u}tzt und zu Lernprozessen angeregt werden k{\"o}nnen. Die Identifizierung von lern- und leistungsf{\"o}rderlichen Zielstrukturen der Arbeitsumgebung w{\"u}rde wertvolle Ansatzpunkte f{\"u}r die Mitarbeiterentwicklung in der betrieblichen Praxis liefern. Im Rahmen von drei empirischen Studien wird der Relevanz der Zielorientierung im Arbeits-kontext nachgegangen. Neben der {\"U}berpr{\"u}fung eines ins Deutsche {\"u}bertragenen und angepassten Mess-instruments zur Erhebung der arbeitsplatzbezogenen Zielorientierung (Studie 1) steht vor allem die Untersuchung m{\"o}glicher Einfl{\"u}sse des Konstrukts auf arbeitsrelevante Variablen im Vordergrund, um f{\"o}rderliche Zielstrukturen zu identifizieren (Studie 1 \& 2). Dar{\"u}ber hinaus werden erstmalig m{\"o}gliche Person-Situation-Interaktionen in diesem Zusammenhang untersucht (Studie 2). Abschließend erfolgt eine Untersuchung m{\"o}glicher Antezedenten der arbeitsplatzbezogenen Zielorientierung, woraus sich erste wichtige Anhaltspunkte f{\"u}r Interventionsmaßnahmen am Arbeitsplatz ableiten lassen (Studie 3). Die Ergebnisse der Studien zeigen, dass insbesondere ein lernzielorientierter Arbeitsplatz f{\"o}rderlich f{\"u}r die untersuchten Variablen wie Lernerfolg, Leistung oder auch berufliche Selbstwirksamkeit ist. In Bezug auf die Interaktion von Person und Situation ergaben sich gemischte Befunde, die kein eindeutiges Interaktionsmuster aufweisen. Bei der Frage, wie ein lernzielorientierter Arbeitsplatz gef{\"o}rdert werden kann, erwies sich vor allem die Art und Weise, wie F{\"u}hrungskr{\"a}fte mit Fehlern umgehen, als relevant. Die Studien liefern demnach wichtige erste Ans{\"a}tze f{\"u}r theoretische und praktische Implikationen, wie Mitarbeiter in Lern- und Leistungsprozessen unterst{\"u}tzt werden k{\"o}nnen.},
  subject      = {Handlung},
  language  = {de}
}
@phdthesis{Klinke2022,
  author    = {Klinke, Christopher Matthias},
  title     = {Experimental investigation of the effect of distal stress induction on threat conditioning in humans},
  doi       = {10.25972/OPUS-22556},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-225562},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2022},
  abstract  = {Stress constitutes a major risk factor for the development of psychiatric disorders, such as PTSD and anxiety disorders, by shifting the brain into a state of sensitization and makes it more vulnerable when being exposed to further aversive events. This was experimentally in-vestigated in rodents by examining the effect of a distal stress induction on threat conditioning, where stress impaired extinction learning and caused spontaneous recovery. However, this effect has never been experimentally investigated in humans, so far. Thus, the aim of this dissertation was to investigate the effect of distal stress on threat conditioning in humans. Therefore, two subsequent studies were conducted. For both studies, the threat conditioning paradigm comprised threat acquisition, extinction learning, and re-extinction. In the threat acquisition phase, two geometrical shapes were used as conditioned stimulus (CS), from which one (CS+) was paired with a painful electric stimulus (unconditioned stimulus, US), but not the other one (CS-). During extinction learning 24 h later and re-extinction seventeen days later, CSs were again presented but without any US delivery. In Study 1, 69 participants underwent either a stress (socially evaluated cold pressor test; SECPT) or sham protocol 10 days prior to threat conditioning. Furthermore, context effects were examined by placing the stress protocol in the same context (context-A stress, and sham group) or a different context (context-B stress group) than conditioning. Results revealed that the context-A, but not context-B, stress group displayed impaired safety learning (i.e. potenti-ation towards CS-) for startle response during threat acquisition. Moreover, the same stress group showed impaired threat extinction, evident in sustained CS discrimination in valence and arousal ratings during extinction learning, and memory recall. In sum, distal stress on the one hand impaired safety learning during threat conditioning on a level of startle response. On the other hand, stress impaired threat extinction on a level of ratings. Noteworthy, the effect of distal stress was only found when the stressor was placed in the same context as later threat learning. Hence, suggesting that the combination of stressor and stressor-associated context exerted the effect on threat extinction. In Study 2, it was examined if distal stress induction could also have an impact on threat and extinction processes without the necessity of context association. Therefore, the same stress (n = 45) or sham protocol (n = 44) as in Study 1 was conducted in a different context than and 24 h prior to a threat conditioning paradigm. Similar to Study 1, weakened extinction learning was found in fear ratings for the stress (vs. sham) group, which was indicated by persistent CS+/CS- differentiation after the first block of extinction trials. Alterations in safety learning towards the CS- during threat acquisition were only supported by significant correlations between stress measures on the stress day and conditioned startle response of the CS- during acquisition. Taken together, in two subsequent studies this dissertation provided first evidence of impaired threat extinction after distal stress induction in humans. Furthermore, impairments in safety learning, as can be observed in PTSD, were additionally demonstrated. Interestingly, the effects were boosted and more profound when associating the stressor to the later learning context. These results have clinical implications as they can be translated to the notion that prior stress exposure makes an individual more vulnerable for later aversive events.},
  subject      = {Stress},
  language  = {en}
}
@phdthesis{RuedtvonCollenberg2021,
  author    = {R{\"u}dt von Collenberg, Cora Freifrau},
  title     = {The role of Ciliary Neurotrophic Factor in hippocampal synaptic plasticity and learning},
  doi       = {10.25972/OPUS-20664},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-206646},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2021},
  abstract  = {Ciliary neurotrophic factor (Cntf) acts as a differentiation and survival factor for different types of neurons and glial cells. It is expressed by peripheral Schwann cells and astrocytes in the central nervous system and mediates its effects via a receptor complex involving CntfRα, LifRß and gp130, leading to downstream activation of Stat3. Recent studies by our group have shown that Cntf modulates neuronal microtubule dynamics via Stat3/stathmin interaction. In a mouse model for motor neuron disease, i.e. pmn, Cntf is able to rescue axonal degeneration through Stat3/stathmin signaling. While these findings suggest a role of Cntf in controlling axonal functions in the neuromuscular system, additional data indicate that Cntf might also play a role in synaptic plasticity in the hippocampus. Electrophysiological recordings in hippocampal organotypic cultures and acute slices revealed a deficit in long-term potentiation (LTP) in Cntf -/- mice. This deficit was rescued by 24 h stimulation with Cntf, combined with an acute application of Cntf during LTP-measurements indicating that Cntf is both necessary and sufficient for hippocampal LTP, and possibly synaptic plasticity. Therefore, Cntf knockout mice were investigated to elucidate this possible role of Cntf in hippocampal LTP and synaptic plasticity. First, we validated the presence of Cntf in the target tissue: in the hippocampus, Cntf was localized in Gfap-positive astrocytes surrounding small blood vessels in the fissure and in meningeal areas close to the dentate gyrus. Laser micro-dissection and qPCR analysis showed a similar distribution of Cntf-coding mRNA validating the obtained immunofluorescent results. Despite the strong LTP deficit in organotypic cultures, in vivo behavior of Cntf -/- mice regarding hippocampus-dependent learning and anxiety-related paradigms was largely inconspicuous. However, western blot analysis of hippocampal organotypic cultures revealed a significant reduction of pStat3 levels in Cntf -/- cultures under baseline conditions, which in turn were elevated upon Cntf stimulation. In order to resolve and examine synaptic structures we turned to in vitro analysis of cultured hippocampal neurons which indicated that pStat3 is predominantly located in the presynapse. In line with these findings, presynapses of Cntf -/- cultures were reduced in size and when in contact to astrocytes, contained less pStat3 immunoreactivity compared to presynapses in wildtype cultures. In conclusion, our findings hypothesize that despite of a largely inconspicuous behavioral phenotype of Cntf -/- mice, Cntf appears to have an influence on pStat3 levels at hippocampal synapses. In a next step these two key questions need to be addressed experimentally: 1) is there a compensatory mechanism by members of the Cntf family, possibly downstream of pStat3, which explains the in vivo behavioral results of Cntf -/- mice and can likewise account for the largely inconspicuous phenotype in CNTF-deficient humans? 2) How exactly does Cntf influence LTP through Stat3 signaling? To unravel the underlying mechanism further experiments should therefore investigate whether microtubule dynamics downstream of Stat3 and stathmin signaling are involved in the Cntf-induced modulation of hippocampal synaptic plasticity, similar to as it was shown in motoneurons.},
  subject      = {Hippocampus},
  language  = {en}
}
@phdthesis{Oberdoerfer2021,
  author    = {Oberd{\"o}rfer, Sebastian},
  title     = {Better Learning with Gaming: Knowledge Encoding and Knowledge Learning Using Gamification},
  doi       = {10.25972/OPUS-21970},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-219707},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2021},
  abstract  = {Computer games are highly immersive, engaging, and motivating learning environments. By providing a tutorial at the start of a new game, players learn the basics of the game's underlying principles as well as practice how to successfully play the game. During the actual gameplay, players repetitively apply this knowledge, thus improving it due to repetition. Computer games also challenge players with a constant stream of new challenges which increase in difficulty over time. As a result, computer games even require players to transfer their knowledge to master these new challenges. A computer game consists of several game mechanics. Game mechanics are the rules of a computer game and encode the game's underlying principles. They create the virtual environments, generate a game's challenges and allow players to interact with the game. Game mechanics also can encode real world knowledge. This knowledge may be acquired by players via gameplay. However, the actual process of knowledge encoding and knowledge learning using game mechanics has not been thoroughly defined, yet. This thesis therefore proposes a theoretical model to define the knowledge learning using game mechanics: the Gamified Knowledge Encoding. The model is applied to design a serious game for affine transformations, i.e., GEtiT, and to predict the learning outcome of playing a computer game that encodes orbital mechanics in its game mechanics, i.e., Kerbal Space Program. To assess the effects of different visualization technologies on the overall learning outcome, GEtiT visualizes the gameplay in desktop-3D and immersive virtual reality. The model's applicability for effective game design as well as GEtiT's overall design are evaluated in a usability study. The learning outcome of playing GEtiT and Kerbal Space Program is assessed in four additional user studies. The studies' results validate the use of the Gamified Knowledge Encoding for the purpose of developing effective serious games and to predict the learning outcome of existing serious games. GEtiT and Kerbal Space Program yield a similar training effect but a higher motivation to tackle the assignments in comparison to a traditional learning method. In conclusion, this thesis expands the understanding of using game mechanics for an effective learning of knowledge. The presented results are of high importance for researches, educators, and developers as they also provide guidelines for the development of effective serious games.},
  subject      = {Serious game},
  language  = {en}
}
@phdthesis{Lyutova2019,
  author    = {Lyutova, Radostina},
  title     = {Functional dissection of recurrent feedback signaling within the mushroom body network of the Drosophila larva},
  doi       = {10.25972/OPUS-18728},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-187281},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2019},
  abstract  = {Behavioral adaptation to environmental changes is crucial for animals' survival. The prediction of the outcome of one owns action, like finding reward or avoiding punishment, requires recollection of past experiences and comparison with current situation, and adjustment of behavioral responses. The process of memory acquisition is called learning, and the Drosophila larva came up to be an excellent model organism for studying the neural mechanisms of memory formation. In Drosophila, associative memories are formed, stored and expressed in the mushroom bodies. In the last years, great progress has been made in uncovering the anatomical architecture of these brain structures, however there is still a lack of knowledge about the functional connectivity. Dopamine plays essential roles in learning processes, as dopaminergic neurons mediate information about the presence of rewarding and punishing stimuli to the mushroom bodies. In the following work, the function of a newly identified anatomical connection from the mushroom bodies to rewarding dopaminergic neurons was dissected. A recurrent feedback signaling within the neuronal network was analyzed by simultaneous genetic manipulation of the mushroom body Kenyon cells and dopaminergic neurons from the primary protocerebral anterior (pPAM) cluster, and learning assays were performed in order to unravel the impact of the Kenyon cells-to-pPAM neurons feedback loop on larval memory formation. In a substitution learning assay, simultaneous odor exposure paired with optogenetic activation of Kenyon cells in fruit fly larvae in absence of a rewarding stimulus resulted in formation of an appetitive memory, whereas no learning behavior was observed when pPAM neurons were ablated in addition to the KC activation. I argue that the activation of Kenyon cells may induce an internal signal that mimics reward exposure by feedback activation of the rewarding dopaminergic neurons. My data further suggests that the Kenyon cells-to-pPAM communication relies on peptidergic signaling via short neuropeptide F and underlies memory stabilization.},
  subject      = {Lernen},
  language  = {en}
}
@phdthesis{Pieger2017,
  author    = {Pieger, Elisabeth},
  title     = {Metacognition and Disfluency - The Effects of Disfluency on Monitoring and Performance},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-155362},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2017},
  abstract  = {In this thesis, metacognition research is connected with fluency research. Thereby, the focus lies on how disfluency can be used to improve metacognitive monitoring (i.e., students` judgments during the learning process). Improving metacognitive monitoring is important in educational contexts in order to foster performance. Theories about metacognition and self-regulated learning suppose that monitoring affects control and performance. Accurate monitoring is necessary to initiate adequate control and better performance. However, previous research shows that students are often not able to accurately monitor their learning with meaningful text material. Inaccurate monitoring can result in inadequate control and low performance. One reason for inaccurate monitoring is that students use cues for their judgments that are not valid predictors of their performance. Because fluency might be such a cue, the first aim of this thesis is to investigate under which conditions fluency is used as a cue for judgments during the learning process. A fluent text is easy to process and, hence, it should be judged as easy to learn and as easy to remember. Inversely, a disfluent text is difficult to process, for example because of a disfluent font type (e.g., Mistral) or because of deleted letters (e.g., l_tt_rs). Hence, a disfluent text should be judged as difficult to learn and as difficult to remember. This assumption is confirmed when students learn with both fluent and disfluent material. When fluency is manipulated between persons, fluency seems to be less obvious as a cue for judgments. However, there are only a few studies that investigated the effects of fluency on judgments when fluency is manipulated between persons. Results from Experiment 1 (using deleted letters for disfluent text) and from Experiment 4 (using Mistral for disfluent text) in this thesis support the assumption that fluency is used as a cue for judgments in between-person designs. Thereby, however, the interplay with the type of judgment and the learning stage seems to matter. Another condition when fluency affects judgments was investigated in Experiment 2 and 3. The aim of these experiments was to investigate if disfluency leads to analytic monitoring and if analytic monitoring sustains for succeeding fluent material. If disfluency activates analytic monitoring that remains for succeeding fluent material, fluency should no longer be used as a cue for judgments. Results widely support this assumption for deleted letters (Experiment 2) as well as for the font type Mistral (Experiment 3). Thereby, again the interplay between the type of judgment and the learning stage matters. Besides the investigation of conditions when fluency is used as a cue for different types of judgments during the learning process, another aim of this thesis is to investigate if disfluency leads to accurate monitoring. Results from Experiment 3 and 4 support the assumption that Mistral can reduce overconfidence. This is the case when fluency is manipulated between persons or when students first learn with a fluent and then with a disfluent text. Dependent from the type of judgment and the learning stage, disfluency can lead even to underconfidence or to improved relative monitoring accuracy (Experiment 4). Improving monitoring accuracy is only useful when monitoring is implemented into better control and better performance. The effect of monitoring accuracy on control and performance was in the focus of Experiment 4. Results show that accurate monitoring does not result in improved control and performance. Thus, further research is required to develop interventions that do not only improve monitoring accuracy but that also help students to implement accurate monitoring into better control and performance. Summing up, the aim of this thesis is to investigate under which conditions fluency is used as a cue for judgments during the learning process, how disfluency can be used to improve monitoring accuracy, and if improved monitoring accuracy leads to improved performance. By connecting metacognition research and fluency research, further theories about metacognition and theories about fluency are specified. Results show that not only the type of fluency and the design, but also the type of judgment, the type of monitoring accuracy, and the learning stage should be taken into account. Understanding conditions that affect the interplay between metacognitive processes and performance as well as understanding the underlying mechanisms is necessary to enable systematic research and to apply findings into educational settings.},
  subject      = {Metakognition},
  language  = {en}
}
@phdthesis{GoebelgebAichele2016,
  author    = {G{\"o}bel [geb. Aichele], Thorsten Philipp},
  title     = {Marginalien als Explikation der lokalen Makrostruktur beim Lernen mit Hypertext},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-148136},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2016},
  abstract  = {Im Rahmen der vorliegenden Arbeit wurden vier Experimente zur Eignung von Marginalien als Lernhilfen im Hypertext durchgef{\"u}hrt. Die grundlegende Annahme lautet dabei, dass Marginalien als Kommentar zum Text aufgefasst werden und somit im Vergleich zu intratextuellen Lernhilfen wie {\"U}berschriften oder absatzeinleitenden Makropropositionen zu einer interaktiven und tieferen Verarbeitung der Lerninhalte f{\"u}hren. Als Lernmedium wurden eine hierarchische Hypertextumgebung zum Thema Fragebogenkonstruktion und eine netzf{\"o}rmige Hypertextumgebung zur Bedeutung des Buchdrucks in der Medientheorie eingesetzt. Experiment 1 (N= 41) verglich mittels between-Design die Lernleistung bei Marginalien mit einer Pr{\"a}sentation derselben Makropropositionen als absatzeinleitende Topic-S{\"a}tze und einer Platzierung der Makropropositionen am Absatzende. Die Ergebnisse zeigen, dass absatzweise Marginalien im Vergleich zu absatzeinleitenden Makropropositionen und der Kontrollgruppe zu einem besseren Abschneiden bei geschlossenen Inferenzfragen f{\"u}hren. Hinsichtlich geschlossener Fragen zur Textbasis konnten jedoch die absatzeinleitenden Makropropositionen im Vergleich mit den beiden anderen Bedingungen die besten Ergebnisse erzielen. Experiment 2 (N= 105) verglich den Einfluss von Marginalien mit {\"U}berschriften und einer Kontrollgruppe ohne absatzweise Explikation der Makrostruktur auf das Schreiben einer Zusammenfassung des Lerntextes. Zus{\"a}tzlich wurden erneut geschlossene Inferenzfragen pr{\"a}sentiert. Erg{\"a}nzend wurde das Rezeptionsverhalten mittels Blickbewegungsmessung ermittelt. Dabei zeigten sich signifikante Unterschiede zwischen {\"U}berschriften und Marginalien. Marginalien wurden in der hierarchischen Hypertextumgebung allgemein seltener gelesen als {\"U}berschriften und zeigten auch hinsichtlich der Anzahl der strategischen Rezeptionen und der absatzeinleitenden Rezeption geringere Werte. Einzig nach der Rezeption des zugeh{\"o}rigen Absatzes wurden Marginalien h{\"a}ufiger konsultiert als {\"U}berschriften. Diese Unterschiede gingen einher mit signifikanten Einbußen der Lernleistung der Marginalienbedingung im Vergleich zur {\"U}berschriftenbedingung. So erinnerten Lerner mit Marginalien weniger explizite Makropropositionen des Lerntextes, weniger Fakteninformationen, sowie weniger Inhalte verschiedener Hypertextknoten und bildeten außerdem weniger eigene Makropropositionen. Hinsichtlich der letzten beiden Variablen war die Marginalienbedingung sogar der Kontrollbedingung unterlegen. Experiment 3 (N = 54) verwendete im Gegensatz zu den Experimenten 1 und 2 einen netzf{\"o}rmig organisierten Hypertext mit embedded Links anstelle eines Navigationsmen{\"u}s. Die untersuchten Versuchsbedingungen sowie die Messung der Lernleistung waren jedoch analog zu Experiment 1. Auch hier konnte ein Effekt von Marginalien auf die Inferenzleistung nachgewiesen werden. Allerdings schnitten Marginalien nur besser als die absatzeinleitenden Makropropositionen ab, wohin-gegen kein Unterschied zur Kontrollbedingung festgestellt werden konnten. Hinsichtlich der Leistung bei geschlossenen Faktenfragen konnte die {\"U}berlegenheit absatzeinleitender Makropropositionen gegen{\"u}ber den anderen beiden Pr{\"a}sentationsformen der Makrostruktur erneut best{\"a}tigt werden. Experiment 4 (N= 75) verglich analog zu Experiment 2 unter Verwendung der netzf{\"o}rmigen Lernumgebung aus Experiment 3 erneut den Einfluss von Marginalien, {\"U}berschriften und einer Kontrollbedingung ohne explizite absatzweise Makropropositionen auf das Schreiben einer Zusammenfassung sowie die Beantwortung geschlossener Inferenzfragen. Auch die Blickbewegungsmessung kam wieder zum Einsatz. Die Ergebnisse von Experiment 2 konnten jedoch nicht best{\"a}tigt werden. Es fanden sich keine signifikanten Unterschiede hinsichtlich der Lernleistung zwischen den drei Versuchsbedingungen und auch hinsichtlich des Rezeptionsverhaltens konnte eine Angleichung von Marginalien und {\"U}berschriften festgestellt werden. Hinsichtlich der Lernleistung wird angenommen, dass die embedded Links in Kombination mit der Instruktion, eine Zusammenfassung zu schreiben mit den {\"U}berschriften und den Marginalien, die jedoch im Vergleich zu Experiment 2 fast vollst{\"a}ndig wie {\"U}berschriften genutzt wurden, interferiert haben und somit eine Hemmung dieser Lernhilfen stattgefunden hat. Anhand der vier durchgef{\"u}hrten Experimente wird gefolgert, dass Marginalien als Explikation der lokalen Makrostruktur sowohl bei hierarchisch strukturiertem Hypertext als auch bei netzf{\"o}rmig organisiertem Hypertext unter der Instruktion eines verstehenden Lernens eine Verbesserung der Inferenzleistung bewirken k{\"o}nnen. Lautet die Instruktion jedoch, eine Zusammenfassung der In-halte zu schreiben, sind Marginalien speziell bei hierarchisch strukturiertem Hypertext wenig geeignet, die Lernleistung zu f{\"o}rdern.},
  subject      = {Hypertext},
  language  = {de}
}
@phdthesis{Scholl2015,
  author    = {Scholl, Christina},
  title     = {Cellular and molecular mechanisms contributing to behavioral transitions and learning in the honeybee},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-115527},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2015},
  abstract  = {The honeybee Apis mellifera is a social insect well known for its complex behavior and the ability to learn tasks associated with central place foraging, such as visual navigation or to learn and remember odor-reward associations. Although its brain is smaller than 1mm² with only 8.2 x 105 neurons compared to ~ 20 x 109 in humans, bees still show amazing social, cognitive and learning skills. They express an age - related division of labor with nurse bees staying inside the hive and performing tasks like caring for the brood or cleaning, and foragers who collect food and water outside the hive. This challenges foragers with new responsibilities like sophisticated navigation skills to find and remember food sources, drastic changes in the sensory environment and to communicate new information to other bees. Associated with this plasticity of the behavior, the brain and especially the mushroom bodies (MBs) - sensory integration and association centers involved in learning and memory formation - undergo massive structural and functional neuronal alterations. Related to this background my thesis on one hand focuses on neuronal plasticity and underlying molecular mechanisms in the MBs that accompany the nurse - forager transition. In the first part I investigated an endogenous and an internal factor that may contribute to the nurse - forager phenotype plasticity and the correlating changes in neuronal network in the MBs: sensory exposure (light) and juvenile hormone (JH). Young bees were precociously exposed to light and subsequently synaptic complexes (microglomeruli, MG) in the MBs or respectively hemolymph juvenile hormone (JH) levels were quantified. The results show that light input indeed triggered a significant decrease in MG density, and mass spectrometry JH detection revealed an increase in JH titer. Interestingly light stimulation in young bees (presumably nurse bees) triggered changes in MG density and JH levels comparable to natural foragers. This indicates that both sensory stimuli as well as the endocrine system may play a part in preparing bees for the behavioral transition to foraging. Considering a connection between the JH levels and synaptic remodeling I used gene knockdown to disturb JH pathways and artificially increase the JH level. Even though the knockdown was successful, the results show that MG densities remained unchanged, showing no direct effect of JH on synaptic restructuring. To find a potential mediator of structural synaptic plasticity I focused on the calcium-calmodulin-dependent protein kinase II (CaMKII) in the second part of my thesis. CaMKII is a protein known to be involved in neuronal and behavioral plasticity and also plays an important part in structural plasticity reorganizing synapses. Therefore it is an interesting candidate for molecular mechanisms underlying MG reorganization in the MBs in the honeybee. Corresponding to the high abundance of CaMKII in the learning center in vertebrates (hippocampus), CaMKII was shown to be enriched in the MBs of the honeybee. Here I first investigated the function of CaMKII in learning and memory formation as from vertebrate work CaMKII is known to be associated with the strengthening of synaptic connections inducing long term potentiation and memory formation. The experimental approach included manipulating CaMKII function using 2 different inhibitors and a specific siRNA to create a CaMKII knockdown phenotype. Afterwards bees were subjected to classical olfactory conditioning which is known to induce stable long-term memory. All bees showed normal learning curves and an intact memory acquisition, short-term and mid-term memory (1 hour retention). However, in all cases long-term memory formation was significantly disrupted (24 and 72 hour retention). These results suggests the necessity of functional CaMKII in the MBs for the induction of both early and late phases of long-term memory in honeybees. The neuronal and molecular bases underlying long-term memory and the resulting plasticity in behavior is key to understanding higher brain function and phenotype plasticity. In this context CaMKII may be an important mediator inducing structural synaptic and neuronal changes in the MB synaptic network.},
  subject      = {Biene},
  language  = {en}
}
@phdthesis{Hlubucek2016,
  author    = {Hlubucek, Lena},
  title     = {Kritische Lebensereignisse als Potenzial f{\"u}r biographische Lernprozesse. Lernprozesse im Kontext eines nicht bestandenen F{\"u}hrungskr{\"a}fte-Assessment-Centers},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-134960},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2016},
  abstract  = {Die hier vorliegende Arbeit leistet einen Beitrag zur Erforschung von Lernprozessen in biographischen Zusammenh{\"a}ngen. Im Zentrum der Betrachtung stehen kritische Lebensereignisse als Impulsgeber. Konkret wird die Untersuchung an dem kritischen Lebensereignis ‚Nichtbestehen eines Assessment Centers (ACs) zur Zulassung einer F{\"u}hrungsaufgabe' durchgef{\"u}hrt. Ziel der Untersuchung ist es, herauszufinden, welche Lernprozesse bei unterschiedlichen Individuen in Folge des Nichtbestehens des ACs zu beobachten sind. Im Rahmen der Untersuchung stehen dabei drei unterschiedliche Analyseebenen im Fokus: die Einzelfallanalyse, die fall{\"u}bergreifende und die fallvergleichende Analyse. Dar{\"u}ber hinaus ist die Untersuchung in einem Paneldesign angelegt, um zus{\"a}tzlich einen Beitrag {\"u}ber die Ver{\"a}nderungen jener Lernprozesse im zeitlichen Verlauf leisten zu k{\"o}nnen. Im Rahmen der Datenerhebung sind daf{\"u}r zw{\"o}lf Interviews in der Panelwelle t1 und aufgrund der Panelmortalit{\"a}t elf Interviews in der Panelwelle t2 mit AC-Teilnehmer(inne)n, die das Verfahren nicht bestanden haben, gef{\"u}hrt worden. F{\"u}r alle drei Ebenen gilt, dass Lernprozesse sowohl auf mentaler als auch auf aktionaler Ebene eintreten und zudem im zeitlichen Verlauf und durch weitere (Lebens-) Ereignisse einer Ver{\"a}nderungsdynamik unterliegen.},
  subject      = {Life-event-Forschung},
  language  = {de}
}
@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}
}