The neural bases of regularity learning

The existence of two separate learning and memory systems has been proposed in experimental psychology and cognitive neuroscience: These systems seem to be specialized for complementary functions, namely (1) fast learning unique episodes and (2) gradual learning regularities across multiple episodes (regularity learning). In three experiments, the present thesis aimed at specifying the neural and cognitive bases of regularity learning. Functional magnetic resonance imaging (fMRI) was used as the main method. In all experiments, volunteers had to learn object-position conjunctions in several experimental trials and blocks. The design of the experiments included two conditions, a context-specific (CS) and an invariant learning (IL) condition. In the CS condition, objects and positions were variably mapped across trials. In the IL condition positions (Experiment [Exp] 1A and 3B) or objects (Exp 1B, 2, and 3A) were held constant within blocks, enabling subjects to extract regularities across trials, i.e. invariant positions or objects in object-position conjunctions. In Exp 1A and Exp 1B, performance increased within blocks in the IL condition, but not in the CS condition. In both experiments, hippocampal activity decreased as a function of learning in the IL condition. Conversely, the hippocampus was activated continuously in the CS condition. In contrast to a right-lateralized hippocampal activation decrease during learning spatial regularities (Exp 1A), learning object regularities (Exp 1B) was associated with a decrease of bilateral hippocampal activity. In both experiments, lateral prefrontal and striatal brain regions showed an increase of activity as a function of learning in the IL condition. In Exp 2, the cognitive processes underlying learning object regularities were investigated in more detail. In six behavioral studies, the influence of object distinctiveness (Exp 2A-2B), memory load and learning duration (Exp 2C-2E), and the effect of simultaneous object-position bindings (Exp 2F) on learning invariant objects in object-position conjunctions was examined. The behavioral data indicate that the increase of object distinctiveness mainly affects overall memory performance, whereas manipulation of the learning duration and the memory load affects the learning process. Moreover, a dissociation of two learning mechanisms could be observed: a process operating within learning blocks and a process operating across blocks. Finally, Exp 3 aimed at specifying whether separable brain regions mediate these two learning mechanisms. In contrast to Exp 1A and 1B, trials were blocked by condition to minimize the probability that subjects based their judgment on a common strategy for both conditions. On a behavioral level, subjects showed a performance increase within and across learning blocks in an object IL condition (Exp 3A) and in a spatial IL condition (Exp 3B), but not in the respective CS conditions. On a neural level, within-block learning was associated with a learning-related decrease of hippocampal and a learning-related increase of prefrontal-striatal activity in both experiments. In contrast, distinct prefrontal-striatal regions were selectively involved in across-block learning. To summarize, on a cognitive level regularity learning within the framework of the present thesis can be characterized by the following criteria: (1) the extraction of regularities across input pattern, (2) the gradual nature of the extraction process, (3) the robust maintenance of extracted regularities over time, and (4) the aggregated representational format of the extracted information. On a neural level, the reduced learning-related hippocampal activation presumably reflects lower binding requirements in the IL condition, since variable objects can be bound to invariant positions or vice versa. Furthermore, the imaging results suggest a domain-specific hemispheric specialization of the hippocampus during regularity learning, reflecting hippocampal sensitivity to perceptual stimulus attributes of invariant episodic features (bottom-up mechanism). The learning-related prefrontal modulation seems to reflect the requirement to extract and maintain regularities across trials and the adjustment of object-position conjunctions on the basis of the extracted knowledge, possibly mediated by rule-like prefrontal representations (top-down mechanism). Finally, the striatum might encode the increased predictability of invariant features as a function of learning and possibly provides an internal reinforcement signal to the PFC. In conclusion, the present results provide new insights into the neural bases of regularity learning and point to a transition of the relative roles of distinct neural systems during the time-course of regularity learning, i.e. learning is accompanied by a shift from a hippocampal to a prefrontal-striatal brain system.Zahlreiche experimentalpsychologische und neurowissenschaftliche Modelle nehmen an, dass qualitativ unterschiedliche Lern- und Gedächtnissysteme existieren. Diese Modelle gehen davon aus, dass ein System für das schnelle Lernen singulärer Episoden spezialisiert ist. Ein weiteres System ist für das graduelle Lernen episoden-übergreifender Regularitäten verantwortlich. Die vorliegende Arbeit untersuchte in mehreren fMRT- und behavioralen Experimenten die neuronalen und kognitiven Grundlagen des Lernens episoden-übergreifender Regularitäten. In jedem Durchgang der Experimente mussten die Versuchspersonen (VP) sequentiell verschiedene Objekte an verschiedenen Positionen enkodieren (Sample-Phase) und diese Objekt-Positionsverknüpfungen bei Päsentation eines Probe-Stimulus abrufen. Das experimentelle Design umfasste 2 Bedingungen, eine Kontrollbedingung (context-specific, CS) und eine Lernbedingung (invariant learning, IL). In der IL-Bedingung wurden Regularitäten innerhalb von experimentellen Blöcken eingeführt. Zwei Varianten der IL-Bedingung wurden verwendet. In einer räumlichen IL-Bedingung wurden innerhalb eines experimentellen Blocks variable Objekte an invarianten Positionen präsentiert. In einer Objekt-IL-Bedingung hingegen wurden invariante Objekte an variablen Positionen präsentiert. Im Gegensatz zu diesen konstanten Positionen bzw. Objekten in der IL-Bedingung wurden in der CS-Bedingung sowohl Positionen als auch Objekte variabel gehalten. Zusammengefasst zeigten VP in den Experimenten der vorliegenden Arbeit auf behavioraler Ebene einen Performanzanstieg in den beiden IL-Bedingungen, nicht jedoch in der CS-Bedingung. Auf neuronaler Ebene zeigte der Hippocampus einen lernrelatierten Aktivierungsabfall in der IL-Bedingung und konstante Aktivierung in der CS-Bedingung. Weiterhin ergab sich ein lernrelatierter Aktivierungsanstieg präfrontal-striataler Areale. Die konstante hippocampale Aktivierung in der CS-Bedingung kann auf weitestgehend konstante relationale Bindungsprozesse zurückgeführt werden. In der CS-Bedingung müssen in jedem Durchgang variable Objekte und variable Positionen gebunden werden. In der IL-Bedingung nehmen diese relationalen Bindungsanforderungen als Funktion des Lernens ab, da variable Objekte und invariante Positionen bzw. vice versa gebunden werden. Diese Abnahme relationaler Bindungsanforderungen scheint zu einer Reduktion hippocampaler Aktivierung im Verlauf des Lernens zu führen. Das vorliegende Datenmuster legt weiter nahe, dass der präfrontale Cortex (PFC) eine wesentliche Rolle bei der Extraktion episoden-übergreifender Regularitäten und der Aufrechterhaltung dieser Regularitäten spielt. In Übereinstimmung mit anderen Studien wird angenommen, dass diese Regularitäten in Form von Gedächtniscodes repräsentiert sind. Neu zu enkodierende Episoden werden dann anhand dieses Gedächtniscodes reorganisiert, was zur Realisierung einer effektiveren Enkodierstrategie und damit einhergehend zu erhöhter präfrontaler Aktivierung führt. Schließlich scheint das Striatum die zunehmende Vorhersagbarkeit invarianter episodischer Merkmale zu enkodieren. Zusammengefasst konnten die vorliegenden Experimente zeigen, dass das Lernen episoden-übergreifender Regularitäten von einem graduellen Übergang von einem hippocampalen zu einem präfrontal-striatalen System begleitet ist

Gewaltprävention in der Schule

Das Ziel der vorliegenden Arbeit bestand darin Rechtfertigungen von Tätern nach einer (hypothetischen) moralischen Regelverletzung (z.B. physische oder verbale Gewalt, sozialer Ausschluss) zu untersuchen. Zu diesem Zweck wurden zwei bereits in der Literatur bekannte Konstrukte herangezogen, nämlich zum Einen die Moral Disengagement Theory von Albert Bandura (1996) und zum Anderen das Konzept des Moral Reasoning von Tina Malti und Kollegen (2009). Nachdem die vorliegenden Literaturbefunde sich ausschließlich mit Kindern im europäischen Ausland beschäftigen, soll dies die erste Arbeit sein, die dieser Frage bei österreichischen Kindern auf den Grund geht. Deshalb wurden die zweiten, dritten und vierten Klassen österreichischer Kooperativer Mittelschulen sowie Hauptschulen untersucht und es lagen anfänglich die Daten von 497 Kindern vor. Nach Aussieben derjenigen Kinder, die zu viele Missings in den Daten aufwiesen bzw. nach einer Kategorisierung in vier Gruppen, nämlich bullies, victims, bully-victims und Unbeteiligte, existierten zwei Stichproben, mit denen je nach Fragestellung gearbeitet wurde. Den Kindern wurden zwei Erhebungsinstrumente vorgelegt, die sich auf oben angeführte Theorien stützten. Das war zum ersten die Moral Disengagement Scale von Bandura (1996) und zum zweiten die Moral-Reasoining Vignetten von Malti und Strohmeier (2009). Die Hauptfragestellung, die darin bestand, ob sich die vier genannten Gruppen signifikant in ihren MD-Werten unterscheiden, erbrachte einen signifikanten Unterschied zwischen den Gruppen bullies und bully-victims und der Gruppe unbeteiligte Kinder. Hinsichtlich des Geschlechts besteht weder ein Unterschied in Bezug auf die Werte auf der MDS, noch bezüglich der Rechtfertigungen, die die Kinder anführen, ausgenommen moralische Rechtfertigungen. Die Fragestellung, ob sich Kinder mit und Kinder ohne Migrationshintergrund hinsichtlich des Scores auf der MDS unterscheiden, fällt nicht signifikant aus. Allerdings gibt es teilweise signifikante Unterschiede in Bezug auf die Zugehörigkeit der Rechtfertigungen, die die Kinder angeben. Jedenfalls sollten die Ergebnisse dahingehend überprüft und weitergeführt werden, als eine größere Stichprobe herangezogen wird, da sich in dieser Untersuchung der Wegfall eines erheblichen Teils der Stichprobe eventuell problematisch gestaltet haben könnte

Cyclosporiasis Outbreak in Germany Associated with the Consumption of Salad

This outbreak is the first foodborne cyclosporiasis outbreak reported from central Europe. The illness was reported in 34 persons who attended luncheons at a German restaurant. The overall attack rate was 85% (34/40). The only foods associated with significant disease risk were two salad side dishes prepared from lettuce imported from southern Europe and spiced with fresh green leafy herbs (p=0.0025)

Spatial planning and health systems: enhancing territorial governance in Alpine Space

ABSTRACT: Health systems in Europe are currently facing numerous critical challenges; demographic change is only one example. In order to successfully cope with those challenges on a long-term perspective, effective territorial governance can positively address upcoming issues in this context. Accordingly, the purpose of this research is to contribute to the enhancement of territorial governance in the Alpine Space (AS) with regard to spatial planning and health systems. The aim is to identify main achievements of previous AS projects funded by the European Union (EU) as well as lessons learned from their realization in order to derive valuable implications for amended health and spatial planning policy development. This includes issues such as transnational needs, potential synergies as well as institutional responsibilities and competences required. Besides the goals, approaches and outputs, also problems and difficulties experienced during the projects are analysed. The unit of analyses are 10 implemented projects of the current AS programming period which can provide achievements of valuable interest in this thematic field. INITIAL SITUATION Demographic change is only one of numerous critical challenges health systems in Europe are currently facing. In order to successfully cope with such challenges on a long-term perspective, changes in present health models and governance of health systems are required. Many highly relevant issues in this context such as the need to improve the quality of life and healthcare of elderly people as well as the provision of access to care for people in medically underserved areas are related to the subjects of 'health systems' and 'spatial planning'. Accordingly, the focus of this research is on those two areas. RESEARCH OBJECTIVE AND APPROACH The purpose of this research is to contribute to the enhancement of territorial governance in the AS with regard to spatial planning and health systems. The research objective is to identify main achievements of previous AS projects as well as lessons learned from their realization. The aim is to derive relevant implications for amended policy development, including issues such as transnational needs, potential synergies as well as institutional responsibilities and competences required. To do so, besides the goals, approaches and outputs, also problems and difficulties experienced during the projects are analysed. Both topics, 'health systems' and 'spatial planning', as pillars of territorial governance, need to be addressed on a transnational level in order to generate practically relevant and valid results. Accordingly, the research question is: "What can be learned from EU-funded AS projects with regard to policy development?" The main achievements of these projects are identified in order to derive valuable lessons for future health and spatial planning policy development. RESEARCH METHOD To answer the research question, desk research and questionnaire inquiry was considered the most appropriate approach. Ten projects were selected amongst those promoted by the EU (funded by the "Alpine Space Programme 2007-13" and the "INTERREG IIB Programme 2000-2006"). These projects aim at improving inclusive growth in the Alpine Space under different dimensions through territorial governance. Based on literature review, a structured question

Unified access to media metadata on the web: Towards interoperability using a core vocabulary.

The goal of the W3C's Media Annotation Working Group (MAWG) is to promote interoperability between multimedia metadata formats on the Web. As experienced by everybody, audiovisual data is omnipresent on today's Web. However, different interaction interfaces and especially diverse metadata formats prevent unified search, access, and navigation. MAWG has addressed this issue by developing an interlingua ontology and an associated API. This article discusses the rationale and core concepts of the ontology and API for media resources. The specifications developed by MAWG enable interoperable contextualized and semantic annotation and search, independent of the source metadata format, and connecting multimedia data to the Linked Data cloud. Some demonstrators of such applications are also presented in this article

Long-range, Seamless Traffic Density Monitoring using Fibre Optic Acoustic Sensing

Accurate real-time traffic sensing is of key importance, especially in the urban environment to be able to optimise traffic flow by intelligent traffic systems (ITS). Often the high density of traffic sensors, needed to achieve an accurate real-time monitoring of important arterial roads, is difficult to implement due to technical contraints or because of high installation cost. Furthermore, existing traffic sensing technology uses sensors that are only able to measure traffic flow on a cross-section of the road where they are installed (typically on a junction), giving no information on the situation in between. An alternative "seamless" measuring technology, is to use floating car data, with Google Maps being the most prominant example. This technology allows to derive traffic information over wide road sections, however it is unable to deliver real- time information, and it relies on the “cooperation” of the data providers (the fleet owner or the mobile phone users). Fiber optic acoustic sensing (FOAS) is a new alternative technology that allows a seamless, real-time monitoring of the road traffic situation over large distances of up to 50 km using the existing telecom fiber optic cable infrastructure. In our previous work we presented an algorithm and results for traffic flow and average speed computation from FOAS raw data at a specific location along a highway and compared it to reference traffic data [1],[2]. In this paper we demonstrate the potential of the seamless nature of the technique by evaluating the traffic density over a length of 25 km of the monitored highway for different days and times of the day

Structures and Dynamics of Complex Guest Molecules in Confinement, Revealed by Solid-State NMR, Molecular Dynamics, and Calorimetry

This review gives an overview of current trends in the investigation of confined molecules such as water, small and higher alcohols, carbonic acids, ethylene glycol, and non-ionic surfactants, such as polyethylene glycol or Triton-X, as guest molecules in neat and functionalized mesoporous silica materials employing solid-state NMR spectroscopy, supported by calorimetry and molecular dynamics simulations. The combination of steric interactions, hydrogen bonds, and hydrophobic and hydrophilic interactions results in a fascinating phase behavior in the confinement. Combining solid-state NMR and relaxometry, DNP hyperpolarization, molecular dynamics simulations, and general physicochemical techniques, it is possible to monitor these confined molecules and gain deep insights into this phase behavior and the underlying molecular arrangements. In many cases, the competition between hydrogen bonding and electrostatic interactions between polar and non-polar moieties of the guests and the host leads to the formation of ordered structures, despite the cramped surroundings inside the pores

A randomized, placebo-controlled, double-blind, prospective trial to evaluate the effect of vildagliptin in new-onset diabetes mellitus after kidney transplantation

<p>Abstract</p> <p>Background</p> <p>New-onset diabetes mellitus after transplantation (NODAT), a frequent and serious complication after transplantation, is associated with decreased graft and patient survival. Currently, it is diagnosed and treated primarily according to existing guidelines for type II diabetes. To date, only a few trials have studied antidiabetic drugs in patients with NODAT. Vildagliptin is a novel dipeptidyl peptidase-4 (DPP-4) inhibitor that improves pancreatic islet function by enhancing both α- and β-cell responsiveness to increased blood glucose. Experimental data show potential protective effects of DPP-4 inhibitors on islet function after exogenous stress stimuli including immunosuppressants. Therefore, the therapy of NODAT with this class of compounds seems attractive. At present, vildagliptin is used to treat type II diabetes as monotherapy or in combination with other antidiabetic drugs, since that it efficiently decreases glycated hemoglobin (HbA1c) values. Additionally, vildagliptin has been shown to be safe in patients with moderately impaired kidney function. This study will evaluate the safety and efficacy of vildagliptin monotherapy in renal transplant recipients with recently diagnosed NODAT.</p> <p>Methods/Design</p> <p>This study is a randomized, placebo-controlled, double-blind, prospective phase II trial. Using the results of routinely performed oral glucose tolerance tests (OGTT) in stable renal transplant patients at our center, we will recruit patients without a history of diabetes and a 2 h glucose value surpassing 200 mg/dl (11.1 mmol/l). They are randomized to receive either 50 mg vildagliptin or placebo once daily. A total of 32 patients with newly diagnosed NODAT will be included. The primary endpoint is the difference in the 2 h glucose value between baseline and the repeated OGTT performed 3 months after treatment start, compared between the vildagliptin- and the placebo-group. Secondary endpoints include changes in HbA1c and fasting plasma glucose (FPG). The safety of vildagliptin in renal transplant patients will be assessed by the number of symptomatic hypoglycemic episodes (glucose <72 mg/dl or 4 mmol/l), the number of adverse events, and possible medication-associated side-effects.</p> <p>Discussion</p> <p>NODAT is a severe complication after kidney transplantation. Few trials have assessed the safety and efficacy of antidiabetic drugs for these patients. The purpose of this study is to assess the safety and efficacy of vildagliptin in renal transplant patients with NODAT.</p> <p>Trial Registration</p> <p>ClinicalTrials.gov NCT00980356</p