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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Effect of Cognitive-Behavioral Therapy on Neural Correlates of Fear Conditioning in Panic Disorder

Kircher, Tilo, Arolt, Volker, Jansen, Andreas, Pyka, Martin, Reinhardt, Isabelle, Kellermann, Thilo, Konrad, Carsten, Lüken, Ulrike, Gloster, Andrew T., Gerlach, Alexander L., Ströhle, Andreas, Wittmann, André, Pfleiderer, Bettina, Wittchen, Hans-Ulrich, Straube, Benjamin 23 October 2013 (has links) (PDF)
Background: Learning by conditioning is a key ability of animals and humans for acquiring novel behavior necessary for survival in a changing environment. Aberrant conditioning has been considered a crucial factor in the etiology and maintenance of panic disorder with agoraphobia (PD/A). Cognitive-behavioral therapy (CBT) is an effective treatment for PD/A. However, the neural mechanisms underlying the effects of CBT on conditioning processes in PD/A are unknown. Methods: In a randomized, controlled, multicenter clinical trial in medication-free patients with PD/A who were treated with 12 sessions of manualized CBT, functional magnetic resonance imaging (fMRI) was used during fear conditioning before and after CBT. Quality-controlled fMRI data from 42 patients and 42 healthy subjects were obtained. Results: After CBT, patients compared to control subjects revealed reduced activation for the conditioned response (CS+ > CS–) in the left inferior frontal gyrus (IFG). This activation reduction was correlated with reduction in agoraphobic symptoms from t1 to t2. Patients compared to control subjects also demonstrated increased connectivity between the IFG and regions of the “fear network” (amygdalae, insulae, anterior cingulate cortex) across time. Conclusions: This study demonstrates the link between cerebral correlates of cognitive (IFG) and emotional (“fear network”) processing during symptom improvement across time in PD/A. Further research along this line has promising potential to support the development and further optimization of targeted treatments.
12

Konnektivität in der Dualen Ausbildung

Bank, Volker, Glaß, Chistiane 29 November 2017 (has links) (PDF)
In der beruflichen Bildung stellt sich in besonderer Weise die Frage nach dem Verhältnis der idealtypischen Lernorte Betrieb und Berufsschule. Obwohl dieser Duplizität der Lernorte offenbar eine besondere bildende Kraft innewohnt, reichen die Forderungen, diese Zweiheit zu gestalten von der radikalen Trennung bis hin zur vollständigen Abstimmung der jeweiligen Aktivitäten von Lehren und Lernen. Richtigerweise wurden von Tenberg, Aprea und Pittich (2012) in einem grundlegenden Positionspapier diese instrumentellen Vorschläge als empirisch gehaltlos kritisiert. Zwischenzeitlich gibt es eine nähere Untersuchung der faktischen Verhältnisse. Dafür wurde an der TU Chemnitz im Rahmen der von eben diesen Autoren federführend lancierten europäischen ConVet-Studie zunächst eine Dokumentenanalyse durchgeführt. Dieses wurde um eine Befragung von Auszubildenden/ Schülerinnen und Schülern sowie von deren Ausbildern und Lehrkräften erweitert. Als ein erster wesentlicher Hinweis ist diesen Untersuchungen zu entnehmen, dass die eine Konnektivität höherer Ordnung bzw. eine abgeschwächte Hypothese der Komplementarität Anspruch auf Gültigkeit besitzen könnten. Die Dokumentenstudie und die Pilotbefragung sollen Grundlage für weitere Studien quantitativer Ausrichtung sein, die einen quantitativ deutlich weitergesteckten Probandenrahmen umfassen sollen.
13

Functional network centrality in obesity: a resting-state and task fMRI study

García-García, Isabel, Jurado, María Ángeles, Garolera, Maite, Marqués-Iturria, Idoia, Horstmann, Annette, Segura, Bàrbara, Pueyo, Roser, Sender-Palacios, María José, Vernet-Vernet, Maria, Villringer, Arno, Junqué, Carme, Margulies, Daniel S., Neumann, Jane January 2015 (has links)
Obesity is associated with structural and functional alterations in brain areas that are often functionally distinct and anatomically distant. This suggests that obesity is associated with differences in functional connectivity of regions distributed across the brain. However, studies addressing whole brain functional connectivity in obesity remain scarce. Here, we compared voxel-wise degree centrality and eigenvector centrality between participants with obesity (n=20) and normal-weight controls (n=21). We analyzed resting state and task-related fMRI data acquired from the same individuals. Relative to normal-weight controls, participants with obesity exhibited reduced degree centrality in the right middle frontal gyrus in the resting-state condition. During the task fMRI condition, obese participants exhibited less degree centrality in the left middle frontal gyrus and the lateral occipital cortex along with reduced eigenvector centrality in the lateral occipital cortex and occipital pole. Our results highlight the central role of the middle frontal gyrus in the pathophysiology of obesity, a structure involved in several brain circuits signaling attention, executive functions and motor functions. Additionally, our analysis suggests the existence of task-dependent reduced centrality in occipital areas; regions with a role in perceptual processes and that are profoundly modulated by attention.
14

Resting-state functional connectivity in the brain and its relation to language development in preschool children

Xiao, Yaqiong 01 December 2017 (has links)
Human infants have been shown to have an innate capacity to acquire their mother tongue. In recent decades, the advent of the functional magnetic resonance imaging (fMRI) technique has made it feasible to explore the neural basis underlying language acquisition and processing in children, even in newborn infants (for reviews, see Kuhl & Rivera-Gaxiola, 2008; Kuhl, 2010) . Spontaneous low-frequency (< 0.1 Hz) fluctuations (LFFs) in the resting brain have been shown to be physiologically meaningful in the seminal study (Biswal et al., 1995) . Compared to task-based fMRI, resting-state fMRI (rs-fMRI) has some unique advantages in neuroimaging research, especially in obtaining data from pediatric and clinical populations. Moreover, it enables us to characterize the functional organization of the brain in a systematic manner in the absence of explicit tasks. Among brain systems, the language network has been well investigated by analyzing LFFs in the resting brain. This thesis attempts to investigate the functional connectivity within the language network in typically developing preschool children and the covariation of this connectivity with children’s language development by using the rs-fMRI technique. The first study (see Chapter 2.1; Xiao et al., 2016a) revealed connectivity differences in language-related regions between 5-year-olds and adults, and demonstrated distinct correlation patterns between functional connections within the language network and sentence comprehension performance in children. The results showed a left fronto-temporal connection for processing syntactically more complex sentences, suggesting that this connection is already in place at age 5 when it is needed for complex sentence comprehension, even though the whole functional network is still immature. In the second study (see Chapter 2.2; Xiao et al., 2016b), sentence comprehension performance and rs-fMRI data were obtained from a cohort of children at age 5 and a one-year follow-up. This study examined the changes in functional connectivity in the developing brain and their relation to the development of language abilities. The findings showed that the development of intrinsic functional connectivity in preschool children over the course of one year is clearly observable and individual differences in this development are related to the advancement in sentence comprehension ability with age. In summary, the present thesis provides new insights into the relationship between intrinsic functional connectivity in the brain and language processing, as well as between the changes in intrinsic functional connectivity and concurrent language development in preschool children. Moreover, it allows for a better understanding of the neural mechanisms underlying language processing and the advancement of language abilities in the developing brain.
15

Cytroconnect – a cloud-based IOT-service as connectivity solution for electrohydraulic systems

Laube, Martin, Günder, Andreas, Bierod, Jan, Jesberger, Volker, Rauch, Stefan 25 June 2020 (has links)
Conventional electrohydraulic solutions integrate easily into modern machine concepts by utilizing field bus technology. Nevertheless, most use cases are limited to machine automation concepts. Integration into higher-level data and IoT systems is the key for positioning of electrohydraulic solutions within the factory of the future. CytroConnect is a new approach for the integration of electrohydraulic systems into IoT environments and the corresponding market offerings. Bosch Rexroth decided not only to integrate IoT-ready features like pre-installed sensor packages but also a modular automation concept providing decentralized intelligence with an open multi-ethernet interface. An edge-to-cloud connectivity stack operated by Bosch turns the target into a Connected Product. The convergence of physical and digital product can be realized. Based on that the digital service CytroConnect solves concrete holistic use cases like visualization and condition monitoring by offering a web-based dashboard of all relevant sensor data that is accessible everywhere. Modular paid add-ons offered as risk-free monthly subscriptions address further smart maintenance and prediction use cases.
16

Effect of Cognitive-Behavioral Therapy on Neural Correlates of Fear Conditioning in Panic Disorder

Kircher, Tilo, Arolt, Volker, Jansen, Andreas, Pyka, Martin, Reinhardt, Isabelle, Kellermann, Thilo, Konrad, Carsten, Lüken, Ulrike, Gloster, Andrew T., Gerlach, Alexander L., Ströhle, Andreas, Wittmann, André, Pfleiderer, Bettina, Wittchen, Hans-Ulrich, Straube, Benjamin January 2013 (has links)
Background: Learning by conditioning is a key ability of animals and humans for acquiring novel behavior necessary for survival in a changing environment. Aberrant conditioning has been considered a crucial factor in the etiology and maintenance of panic disorder with agoraphobia (PD/A). Cognitive-behavioral therapy (CBT) is an effective treatment for PD/A. However, the neural mechanisms underlying the effects of CBT on conditioning processes in PD/A are unknown. Methods: In a randomized, controlled, multicenter clinical trial in medication-free patients with PD/A who were treated with 12 sessions of manualized CBT, functional magnetic resonance imaging (fMRI) was used during fear conditioning before and after CBT. Quality-controlled fMRI data from 42 patients and 42 healthy subjects were obtained. Results: After CBT, patients compared to control subjects revealed reduced activation for the conditioned response (CS+ > CS–) in the left inferior frontal gyrus (IFG). This activation reduction was correlated with reduction in agoraphobic symptoms from t1 to t2. Patients compared to control subjects also demonstrated increased connectivity between the IFG and regions of the “fear network” (amygdalae, insulae, anterior cingulate cortex) across time. Conclusions: This study demonstrates the link between cerebral correlates of cognitive (IFG) and emotional (“fear network”) processing during symptom improvement across time in PD/A. Further research along this line has promising potential to support the development and further optimization of targeted treatments.
17

Encoding and Information Transmission in Synaptically Coupled Neuronal Populations

Knoll, Gregory 24 February 2023 (has links)
In dieser Arbeit versuche ich, den neuronalen Code, d. h. die Art und Weise, wie die Nervenzellen des Gehirns Informationen in ihrer Aktivität übertragen und verarbeiten, besser zu verstehen, indem ich die Kodierung von Stimuli in neuronalen Systemen untersuche. Zu diesem Zweck analysiere ich die Veränderungen in der Dynamik von neuronalen Standardmodellen, die im Rahmen der statistischen Physik entwickelt wurden, in Bezug auf Veränder- ungen der Parameter und der Konnektivität bei Vorhandensein bzw. Fehlen eines Reizes. Ich verwende informationstheoretische Maße, um die Fähigkeit neuronaler Populationen, empfangene Informationen durch ihren Output zu übertragen, zu quantifizieren. Die vorgestellten Ergebnisse bauen auf einer Vielzahl früherer Studien über unverbundene und rekurrente neuronale Pop- ulationen auf. Einige dieser Studien heben zwei neuronale Code-Kandidaten hervor, die unterschiedliche Profile der Informationsfilterung aufweisen: einen Integrationscode, der als Tiefpass-Informationsfilter fungiert, und einen Synchroniecode, der als Bandpassfilter fungiert. Das Ziel der vorliegenden Arbeit ist es, die Ergebnisse dieser Studien auf Netzwerke mit einem höheren Konnektivitätsgrad, wie er im Kortex beobachtet wird, auszuweiten. / In this thesis I attempt to better understand the neural code, or the way in which the nerve cells of the brain transmit and process information in their activity, through the investigation of stimulus encoding in neural systems. To this end, I analyze changes in the dynamics of standard neuronal models, de- veloped in the framework of statistical physics, to variations in parameters and connectivity in the presence versus the absence of a stimulus. In conjunction, information theoretical measures are utilized to quantify the ability of neu- ronal populations to transmit received information through their output. The presented results build upon a multitude of previous studies of both uncon- nected and recurrent neural populations. Some of these studies highlight two neural code candidates that have distinct information filtering profiles: an in- tegration code that acts as a low-pass information filter and a synchrony code that acts as a bandpass filter. In the following, synaptic connectivity is added in diverse ways in order to extend results of these studies to networks with a higher level of connectivity, as observed in the cortex.
18

Bursting dynamics and topological structure of in vitro neuronal networks / Dynamik von Bursts und topologische Struktur von neuronalen Netzwerken in vitro

Stetter, Frank Olav 22 October 2012 (has links)
No description available.
19

Graph Metrics of Structural Brain Networks in Individuals with Schizophrenia and Healthy Controls: Group Differences, Relationships with Intelligence, and Genetics

Yeo, Ronald A., Ryman, Sephira G., van den Heuvel, Martijn P., de Reus, Marcel A., Jung, Rex E., Pommy, Jessica, Mayer, Andrew R., Ehrlich, Stefan, Schulz, S. Charles, Morrow, Eric M., Manoach, Dara, Ho, Beng-Choon, Sponheim, Scott R., Calhoun, Vince D. 02 June 2020 (has links)
Objectives: One of the most prominent features of schizophrenia is relatively lower general cognitive ability (GCA). An emerging approach to understanding the roots of variation in GCA relies on network properties of the brain. In this multi-center study, we determined global characteristics of brain networks using graph theory and related these to GCA in healthy controls and individuals with schizophrenia. Methods: Participants (N = 116 controls, 80 patients with schizophrenia) were recruited from four sites. GCA was represented by the first principal component of a large battery of neurocognitive tests. Graph metrics were derived from diffusion-weighted imaging. Results: The global metrics of longer characteristic path length and reduced overall connectivity predicted lower GCA across groups, and group differences were noted for both variables. Measures of clustering, efficiency, and modularity did not differ across groups or predict GCA. Follow-up analyses investigated three topological types of connectivity—connections among high degree “rich club” nodes, “feeder” connections to these rich club nodes, and “local” connections not involving the rich club. Rich club and local connectivity predicted performance across groups. In a subsample (N = 101 controls, 56 patients), a genetic measure reflecting mutation load, based on rare copy number deletions, was associated with longer characteristic path length. Conclusions: Results highlight the importance of characteristic path lengths and rich club connectivity for GCA and provide no evidence for group differences in the relationships between graph metrics and GCA.
20

Neural Correlates of Procedural Variants in Cognitive-Behavioral Therapy: A Randomized, Controlled Multicenter fMRI Study

Straube, Benjamin, Lueken, Ulrike, Jansen, Andreas, Konrad, Carsten, Gloster, Andrew T., Gerlach, Alexander L., Ströhle, Andreas, Wittmann, André, Pfleiderer, Bettina, Gauggel, Siegfried, Wittchen, Ulrich, Arolt, Volker, Kircher, Tilo 05 August 2020 (has links)
Background: Cognitive behavioral therapy (CBT) is an effective treatment for panic disorder with agoraphobia (PD/AG). It is unknown, how variants of CBT differentially modulate brain networks involved in PD/AG. This study was aimed to evaluate the effects of therapist-guided (T+) versus selfguided (T–) exposure on the neural correlates of fear conditioning in PD/AG. Method: In a randomized, controlled multicenter clinical trial in medication-free patients with PD/AG who were treated with 12 sessions of manualized CBT, functional magnetic resonance imaging (fMRI) was used during fear conditioning before (t1) and after CBT (t2). Quality-controlled fMRI data from 42 patients and 42 healthy subjects (HS) were obtained. Patients were randomized to two variants of CBT (T+, n = 22, and T–, n = 20). Results: The interaction of diagnosis (PD/AG, HS), treatment group (T+, T–), time point (t1, t2) and stimulus type (conditioned stimulus: yes, no) revealed activation in the left hippocampus and the occipitotemporal cortex. The T+ group demonstrated increased activation of the hippocampus at t2 (t2 > t1), which was positively correlated with treatment outcome, and a decreased connectivity between the left inferior frontal gyrus and the left hippocampus across time (t1 > t2). Conclusion: After T+ exposure, contingency-encoding processes related to the posterior hippocampus are augmented and more decoupled from processes of the left inferior frontal gyrus, previously shown to be dysfunctionally activated in PD/AG. Linking single procedural variants to neural substrates offers the potential to inform about the optimization of targeted psychotherapeutic interventions.

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