GesundEuropan Campus Rottal-InnZeitschriftenartikel
Anna-Maria Kasparbauer, D. Rujescu, M. Riedel, O. Pogarell, A. Costa, T. Meindl, C. La Fougère, U. Ettinger
Methylphenidate Effects on Brain Activity as a Function of SLC6A3 Genotype and Striatal Dopamine Transporter Availability
Neuropsychopharmacology, vol. 40, pp. 736-745
2015
DOI: 10.1038/npp.2014.240
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We pharmacologically challenged catecholamine reuptake, using methylphenidate, to investigate its effects on brain activity during a motor response inhibition task as a function of the 3′-UTR variable number of tandem repeats (VNTR) polymorphism of the dopamine transporter (DAT) gene (SLC6A3) and the availability of DATs in the striatum. We measured the cerebral hemodynamic response of 50 healthy males during a Go/No-Go task, a measure of cognitive control, under the influence of 40 mg methylphenidate and placebo using 3T functional magnetic resonance imaging. Subjects were grouped into 9-repeat (9R) carriers and 10/10 homozygotes on the basis of the SLC6A3 VNTR. During successful no-go trials compared with oddball trials, methylphenidate induced an increase of blood oxygen level-dependent (BOLD) signal for carriers of the SLC6A3 9R allele but a decrease in 10/10 homozygotes in a thalamocortical network. The same pattern was observed in caudate and inferior frontal gyrus when successful no-go trials were compared with successful go trials. We additionally investigated in a subset of 35 participants whether baseline striatal DAT availability, ascertained with 123I-FP-CIT single photon emission computed tomography, predicted the amount of methylphenidate-induced change in hemodynamic response or behavior. Striatal DAT availability was nominally greater in 9R carriers compared with 10/10 homozygotes (d=0.40), in line with meta-analyses, but did not predict BOLD or behavioral changes following MPH administration. We conclude that the effects of acute MPH administration on brain activation are dependent on DAT genotype, with 9R carriers showing enhanced BOLD following administration of a prodopaminergic compound.
GesundEuropan Campus Rottal-InnZeitschriftenartikel
Anna-Maria Kasparbauer, N. Merten, D. Aichert, N. Wöstmann, T. Meindl, D. Rujescu, U. Ettinger
Association of COMT and SLC6A3 Polymorphisms With Impulsivity, Response Inhibition and Brain Function
Cortex, vol. 71, no. October, pp. 219-231
2015
DOI: 10.1016/j.cortex.2015.07.002
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Evidence of the genetic correlates of inhibitory control is scant. Two previously studied dopamine-related polymorphisms, COMT rs4680 and the SLC6A3 3′ UTR 40-base-pair VNTR (rs28363170), have been associated with response inhibition, however with inconsistent findings. Here, we investigated the influence of these two polymorphisms in a large healthy adult sample (N = 515) on a response inhibition battery including the antisaccade, stop-signal, go/no-go and Stroop tasks as well as a psychometric measure of impulsivity (Barratt Impulsiveness Scale) (Experiment 1). Additionally, a subsample (N = 144) was studied while performing the go/no-go, stop-signal and antisaccade tasks in 3T fMRI (Experiment 2). In Experiment 1, we did not find any significant associations of COMT or SLC6A3 with inhibitory performance or impulsivity. In Experiment 2, no association of COMT with BOLD was found. However, there were consistent main effects of SLC6A3 genotype in all inhibitory contrasts: Homozygosity of the 10R allele was associated with greater fronto–striatal BOLD response than genotypes with at least one 9R allele. These findings are consistent with meta-analyses showing that the 10R allele is associated with reduced striatal dopamine transporter expression, which in animal studies has been found to lead to increased extracellular dopamine levels. Our study thus supports the involvement of striatal dopamine in the neural mechanisms of cognitive control, in particular response inhibition.
GesundEuropan Campus Rottal-InnZeitschriftenartikel
I. Meyhöfer, M. Steffens, Anna-Maria Kasparbauer, P. Grant, B. Weber, U. Ettinger
Neural Mechanisms of Smooth Pursuit Eye Movements in Schizotypy
Human Brain Mapping, vol. 36, no. 1, pp. 340-353
2015
DOI: 10.1002/hbm.22632
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Patients with schizophrenia as well as individuals with high levels of schizotypy are known to have deficits in smooth pursuit eye movements (SPEM). Here, we investigated, for the first time, the neural mechanisms underlying SPEM performance in high schizotypy. Thirty‐one healthy participants [N = 19 low schizotypes, N = 12 high schizotypes (HS)] underwent functional magnetic resonance imaging at 3T with concurrent oculographic recording while performing a SPEM task with sinusoidal stimuli at two velocities (0.2 and 0.4 Hz). Behaviorally, a significant interaction between schizotypy group and velocity was found for frequency of saccades during SPEM, indicating impairments in HS in the slow but not the fast condition. On the neural level, HS demonstrated lower brain activation in different regions of the occipital lobe known to be associated with early sensory and attentional processing and motion perception (V3A, middle occipital gyrus, and fusiform gyrus). This group difference in neural activation was independent of target velocity. Together, these findings replicate the observation of altered pursuit performance in highly schizotypal individuals and, for the first time, identify brain activation patterns accompanying these performance changes. These posterior activation differences are compatible with evidence of motion processing deficits from the schizophrenia literature and, therefore, suggest overlap between schizotypy and schizophrenia both on cognitive‐perceptual and neurophysiological levels. However, deficits in frontal motor areas observed during pursuit in schizophrenia were not seen here, suggesting the operation of additional genetic and/or illness‐related influences in the clinical disorder.
DigitalBauingenieurwesen und UmwelttechnikBeitrag (Sammelband oder Tagungsband)
C. Ryll, Gerd Maurer
Integrale Planung ist Kopfsache
Christine Ryll im Gespräch mit Gerd Maurer
BIM – Building Information Modeling – Management, Methoden und Strategien für den Planungsprozess – Beispiele aus der Praxis., München
2015
DigitalAngewandte InformatikBeitrag (Sammelband oder Tagungsband)
K. Berger, Y. Koudota, Marcus Barkowsky, P. Le Callet
Subjective Quality Assessment Comparing UHD and HD Resolution in HEVC Transmission Chain
2015 Seventh International Workshop on Quality of Multimedia Experience (QoMEX)
2015
Abstract anzeigen
Ultra High Definition Television (UHDTV) is an emerging broadcasting system, aiming to replace the current High Definition Television (HDTV) in the near future. One aspect of UHDTV is to allow for higher resolutions, notably UHD1, which requires a four times increased datarate for uncompressed transmission compared to Full-HD resolution. As bandwidth for transmission channels in television broadcast is often a fixed value, this study provides information about the perceived quality for transmitting UHD1 content compared to Full-HD content at the same bitrate encoded with HEVC. Content influence is tested with 15 video contents and 4 bitrates are individually chosen per content to span the range of the perceptual scale. The methodology of Absolute Category Rating with Hidden Reference (ACR-HR) is used to collect votes from 24 viewers. The statistical analysis of the collected data shows that, in most cases, there is no significant quality difference between videos transmitted in Full-HD and UHD1 resolution but that the results strongly depend on the content type and on the capture quality. It is also shown that the required bitrate for achieving a chosen broadcast quality level varies with content by a factor of about 14 in HEVC coding.
DigitalAngewandte InformatikZeitschriftenartikel
Marcus Barkowsky, E. Masala, G. van Wallendael, K. Brunnström, N. Staelens, P. Le Callet
Objective Video Quality Assessment ‐- Towards Large Scale Video Database Enhanced Model Development
IEICE Transactions on Communications, vol. E-98b, no. 1, pp. 2-11
2015
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The current development of video quality assessment algorithms suffers from the lack of available video sequences for training, verification and validation to determine and enhance the algorithm's application scope. The Joint Effort Group of the Video Quality Experts Group (VQEG-JEG) is currently driving efforts towards the creation of large scale, reproducible, and easy to use databases. These databases will contain bitstreams of recent video encoders (H.264, H.265), packet loss impairment patterns and impaired bitstreams, pre-parsed bitstream information into files in XML syntax, and well-known objective video quality measurement outputs. The database is continuously updated and enlarged using reproducible processing chains. Currently, more than 70,000 sequences are available for statistical analysis of video quality measurement algorithms. New research questions are posed as the database is designed to verify and validate models on a very large scale, testing and validating various scopes of applications, while subjective assessment has to be limited to a comparably small subset of the database. Special focus is given on the principles guiding the database development, and some results are given to illustrate the practical usefulness of such a database with respect to the detailed new research questions.
Angewandte WirtschaftswissenschaftenBuch (Monographie)
A. Eck, S. Gralka, J. Heller, Wolfgang Nagl, J. Ragnitz
Hochschulfinanzierung in Mecklenburg-Vorpommern
ifo Dresden Studien, München, vol. 75
2015
ISBN: 978-3-88512-561-7
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Im Land Mecklenburg-Vorpommern finden sich zwei staatliche (Voll-)Universitäten, drei staatliche Fachhochschulen und eine staatliche Hochschule für Musik und Theater. Im Vergleich zu den Einnahmen des Landes steigen die Finanzmittel der Hochschulen überproportional. Im Rahmen des Forschungsprojektes sollte deshalb die Finanzmittelausstattung und die Leistung der Hochschulen in Mecklenburg-Vorpommern vergleichend untersucht werden. Dabei wurden die Finanzierung der Hochschulen im Allgemeinen, die Verteilung der Finanzmittel sowie die Qualität der Lehre und Forschung sowohl im Ländervergleich als auch gegenüber ausgewählten einzelnen Vergleichshochschulen analysiert.
DigitalAngewandte WirtschaftswissenschaftenTC GrafenauZeitschriftenartikel
Michael Scholz, V. Dorner, M. Franz, O. Hinz
Measuring consumers' willingness to pay with utility-based recommendation systems
Decision Support Systems, vol. 72, no. April
2015
DOI: 10.1016/j.dss.2015.02.006
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Our paper addresses two gaps in research on recommendation systems: first, leveraging them to predict consumers' willingness to pay; second, estimating non-linear utility functions – which are generally held to provide better approximations of consumers' preference structures than linear functions – at a reasonable level of cognitive consumer effort. We develop an approach to simultaneously estimate exponential utility functions and willingness to pay at a low level of cognitive consumer effort. The empirical evaluation of our new recommendation system's utility and willingness to pay estimates with the estimates of a system based on linear utility functions indicates that exponential utility functions are better suited for predicting optimal recommendation ranks for products. Linear utility functions perform better in estimating consumers' willingness to pay. Based on our experimental data set, we show how retailers can use these willingness to pay estimates for profit-maximizing pricing decisions.
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