Funktionelle MRT zur Charakterisierung der neuronalen Korrelate des Multi-Taskings unter besonderer Berücksichtigung geschlechtsbezogener Unterschiede

Die Beurteilung antibakterieller Aktivität von ausgewählten Pflanzen war das Ziel dieses Projekts.Der Ammoniakextrakt, gewonnen aus den Wurzeln der U. tomentosa wies einen großen Alkaloidgehalt auf, inhibierte das Bakterienwachstum unterschiedlicher Stämme des Gram-positiven Bakteriums Staphylococcus aureus.Der Modulation Assay, durchgeführt mit dem ethanolischen Rohextrakt der Uncaria, ergab keine Beeinflussung der NorA Efflux Pump von SA-1199B.Zwei pentazyklische Oxindolalkaloide (POA) wurden aus dem pulverisierten Wurzelmaterial von U. tomentosa isoliert. Die durchgeführte Strukturaufklärung basiert auf der Interpretation von ein- und zweidimensionalen NMR Spektren.Der klinische S. aureus Stamm SA-1199B war sensitiv gegenüber dem isolierten POA Isopteropodine (MHK = 512 g/mL).Das zweite isolierte POA war Mitraphylline. Das biologische Screening zeigte keine antibakterielle Aktivität gegen Staphylococcus aureus.Die ethanolischen Extrakte aus den Zwiebeln von A. atropurpureum, A. caeruleum, A. caesium, A. falcifolium, A. lenkoranicum, A. litvinovii, A. macranthum, A. maximowiczii `alba`, A. texanum, A. tschimganicum, A. unifolium, B. californica and B. vernum ergab keine bakterielle Wachstumshemmung von S. aureus. A. caesium und A. falcifolium zeigten interessante Farbreaktionen mit den Sprühreagenz Vanillin. Die beiden Spezies A. unifolium and A. texanum entwickelten einen deutlichen Knoblauchgeruch während des Zerkleinerns.Der ethanolische Extrakt der Zwiebel von A. memoria-corsii `Howardii` und A. belladonna und die Chloroformextrakte der Zwiebel von C. powellii and C. powelli `alba` ergab keine weitere bakterielle Inhibition von S. aureus. Die Pflanzenextrakte, gewonnen aus A. blanda und A. thalictroides, zeigten keine Wirkung auf das Staphylokokkenwachstum.Einige Ansätze wurden im Zuge dieser Diplomarbeit gefunden, und die gewonnenen Resultate fordern umso mehr nach zusätzlichen phytochemischen und mikrobiologischen Untersuchungen.The assessment of anti-staphylococcal activity of the selected plants was aimed during the entire course of this project. MIC testing with the ammonia extract from the root of U. tomentosa, which had high alkaloid content, revealed antibacterial activity against different strains of the Gram-positive bacterium Staphylococcus aureus. The modulation assay of the ethanolic crude extract yielded no influence on the NorA efflux pump of SA-1199B.Two pentacyclic oxindole alkaloids (POA) were isolated from the pulverised root material of U. tomentosa. Structural elucidation was made on the basis of the interpretation of one- and two dimensional NMR spektra. The SA-1199B showed susceptibility against the alkaloid isopteropodine (MIC = 512 g/mL). The other POA isolated was mitraphylline. Biological screening showed no anti-staphylococcal activity against Staphylococcus aureus. The ethanolic bulb extracts of A. atropurpureum, A. caeruleum, A. caesium, A. falcifolium, A. lenkoranicum, A. litvinovii, A. texanum, A. tschimganicum, A. unifolium, B. californica and B. vernum, and rhizomes of A. macranthum and A. maximowiczii `alba`, yielded no bacterial growth inhibition of SA-1199B. A. caesium and A. falcifolium displayed interesting colour reactions by being visualized with Vanillin sulphuric acid spray reagent, as well as in particular A. unifolium and A. texanum had the distinctive ?garlic? smell, while chopping. The ethanolic crude extract of bulbs of A. memoria-corsii `Howardii` and A. belladonna and the chloroform extraction of C. powellii and C. powellii `alba` bulbs revealed no further bacterial growth inhibition of S. aureus. The crude extract obtained from the bulbs of A. blanda and the rhizomes of A. thalictroides had no anti-staphylococcal activity either. Some basic approaches have been achieved during the course of this project, and obtained results call even more for additional phytochemical and microbiological investigation in the future.Melanie TscherneggZsfassung in engl. SpracheGraz, Univ., Dipl.-Arb., 2011(VLID)21596

FMRI to probe sex-related differences in brain function with multitasking.

Although established as a general notion in society, there is no solid scientific foundation for the existence of sex-differences in multitasking. Reaction time and accuracy in dual task conditions have an inverse relationship relative to single task, independently from sex. While a more disseminated network, parallel to decreasing accuracy and reaction time has been demonstrated in dual task fMRI studies, little is known so far whether there exist respective sex-related differences in activation.We subjected 20 women (mean age = 25.45; SD = 5.23) and 20 men (mean age = 27.55; SD = 4.00) to a combined verbal and spatial fMRI paradigm at 3.0T to assess sex-related skills, based on the assumption that generally women better perform in verbal tasks while men do better in spatial tasks. We also obtained behavioral tests for verbal and spatial intelligence, attention, executive functions, and working memory.No differences between women and men were observed in behavioral measures of dual-tasking or cognitive performance. Generally, brain activation increased with higher task load, mainly in the bilateral inferior and prefrontal gyri, the anterior cingulum, thalamus, putamen and occipital areas. Comparing sexes, women showed increased activation in the inferior frontal gyrus in the verbal dual-task while men demonstrated increased activation in the precuneus and adjacent visual areas in the spatial task.Against the background of equal cognitive and behavioral dual-task performance in both sexes, we provide first evidence for sex-related activation differences in functional networks for verbal and spatial dual-tasking

Schizophrenia and category-selectivity in the brain : normal for faces but abnormal for houses.

Face processing is regularly found to be impaired in schizophrenia (SZ), thus suggesting that social malfunctioning might be caused by dysfunctional face processing. Most studies focused on emotional face processes, whereas non-emotional face processing received less attention. While current reports on abnormal face processing in SZ are mixed, examinations of non-emotional face processing compared to adequate control stimuli may clarify whether SZ is characterized by a face-processing deficit. Patients with SZ (n=28) and healthy controls (n=30) engaged in an fMRI scan where images of non-emotional faces and houses were presented. A simple inverted-picture detection task warranted the participants' attention. Region of interest (ROI) analyses were conducted on face-sensitive regions including the fusiform face area, the occipital face area, and the superior temporal sulcus. Scene-sensitivity was assessed in the parahippocampal place area (PPA) and served as control condition. Patients did not show aberrant face-related neural processes in face-sensitive regions. This finding was also evident when analyses were done on individually defined ROIs or on in-house-localizer ROIs. Patients revealed a decreased specificity toward house stimuli as reflected in decreased neural response toward houses in the PPA. Again, this result was supported by supplementary analyses. Neural activation toward neutral faces was not found to be impaired in SZ, therefore speaking against an overall face-processing deficit. Aberrant activation in scene-sensitive PPA is also found in assessments of memory processes in SZ. It is up to future studies to show how impairments in PPA relate to functional outcome in SZ.(VLID)250866

Significant activation patterns (local maxima) for the spatial dual-task condition.

<p>Significant activation patterns (local maxima) for the spatial dual-task condition.</p

Dual-task paradigm: A: verbal-, spatial-, and working memory single-task.

<p>Yes/No decisions over equality for the verbal task in terms of meaning, for the spatial task in term of rotation and for the working memory in terms of its color in a one-back task decision. B: Combination of working-memory task, and verbal or spatial single-task. C: Example of the verbal dual-task. Deciding over both tasks with a stimulus-onset-asynchrony (SOA) of 200 ms.</p

Significant activation differences (local maxima) for the verbal dual-task condition (women > men).

<p>Significant activation differences (local maxima) for the verbal dual-task condition (women > men).</p

Reaction times for all single-tasks and dual-tasks.

<p>The scatter plots show the actual data of all 38 participants for visual verification of the distribution.</p

Activation-patterns for all verbal and spatial dual-tasks compared with single-tasks.

<p>(A) Activation patterns for verbal and spatial dual-task compared with single-task over all subjects. (B) Sex related differences for verbal and spatial dual-task compared with single-task. Orientation: right /left.</p