@phdthesis{Dieler2011, author = {Dieler, Alica Christina}, title = {Investigation of variables influencing cognitive inhibition: from the behavioral to the molecular level}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-65955}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2011}, abstract = {The present work investigated the neural mechanisms underlying cognitive inhibition/thought suppression in Anderson's and Green's Think/No-Think paradigm (TNT), as well as different variables influencing these mechanisms at the cognitive, the neurophysiological, the electrophysiological and the molecular level. Neurophysiological data collected with fNIRS and fMRI have added up to the existing evidence of a fronto-hippocampal network interacting during the inhibition of unwanted thoughts. Some evidence has been presented suggesting that by means of external stimulation of the right dlPFC through iTBS thought suppression might be improved, providing further evidence for an implication of this region in the TNT. A combination of fNIRS with ERP has delivered evidence of a dissociation of early condition-independent attentional and later suppression-specific processes within the dlPFC, both contributing to suppression performance. Due to inconsistencies in the previous literature it was considered how stimulus valence would influence thought suppression by manipulating the emotional content of the to-be-suppressed stimuli. Findings of the current work regarding the ability to suppress negative word or picture stimuli have, however, been inconclusive as well. It has been hypothesized that performance in the TNT might depend on the combination of valence conditions included in the paradigm. Alternatively, it has been suggested that inconsistent findings regarding the suppression of negative stimuli or suppression at all might be due to certain personality traits and/or genetic variables, found in the present work to contribute to thought inhibition in the TNT. Rumination has been shown to be a valid predictor of thought suppression performance. Increased ruminative tendencies led to worse suppression performance which, in the present work, has been linked to less effective recruitment of the dlPFC and in turn less effective down-regulation of hippocampal activity during suppression trials. Trait anxiety has also been shown to interrupt thought suppression despite higher, however, inefficient recruitment of the dlPFC. Complementing the findings regarding ruminative tendencies and decreased thought inhibition a functional polymorphism in the KCNJ6 gene, encompassing a G-to-A transition, has been shown to disrupt thought suppression despite increased activation of the dlPFC. Through the investigation of thought suppression at different levels, the current work adds further evidence to the idea that the TNT reflects an executive control mechanism, which is sensitive to alterations in stimulus valence to some extent, neurophysiological functioning as indicated by its sensitivity to iTBS, functional modulations at the molecular level and personality traits, such as rumination and trait anxiety.}, subject = {Kognitiver Prozess}, language = {en} } @article{LudwigSaemannAlexanderetal.2013, author = {Ludwig, K. U. and S{\"a}mann, P. and Alexander, M. and Becker, J. and Bruder, J. and Moll, K. and Spieler, D. and Czisch, M. and Warnke, A. and Docherty, S. J. and Davis, O. S. P. and Plomin, R. and N{\"o}then, M. M. and Landerl, K. and M{\"u}ller-Myhsok, B. and Hoffmann, P. and Schumacher, J. and Schulte-K{\"o}rne, G. and Czamara, D.}, title = {A common variant in Myosin-18B contributes to mathematical abilities in children with dyslexia and intraparietal sulcus variability in adults}, series = {Translational Psychiatry}, volume = {3}, journal = {Translational Psychiatry}, number = {e229}, doi = {10.1038/tp.2012.148}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-131513}, year = {2013}, abstract = {The ability to perform mathematical tasks is required in everyday life. Although heritability estimates suggest a genetic contribution, no previous study has conclusively identified a genetic risk variant for mathematical performance. Research has shown that the prevalence of mathematical disabilities is increased in children with dyslexia. We therefore correlated genome-wide data of 200 German children with spelling disability, with available quantitative data on mathematic ability. Replication of the top findings in additional dyslexia samples revealed that rs133885 was a genome-wide significant marker for mathematical abilities\((P_{comb}=7.71 x 10^{-10}, n=699)\), with an effect size of 4.87\%. This association was also found in a sample from the general population (P=0.048, n=1080), albeit with a lower effect size. The identified variant encodes an amino-acid substitution in MYO18B, a protein with as yet unknown functions in the brain. As areas of the parietal cortex, in particular the intraparietal sulcus (IPS), are involved in numerical processing in humans, we investigated whether rs133885 was associated with IPS morphology using structural magnetic resonance imaging data from 79 neuropsychiatrically healthy adults. Carriers of the MYO18B risk-genotype displayed a significantly lower depth of the right IPS. This validates the identified association between rs133885 and mathematical disability at the level of a specific intermediate phenotype.}, language = {en} }