openHSU – Research Showcase

Frequent switching between two tasks afforded by the same stimuli is associated with between-task congruency effects, that is, relatively impaired performance when a stimulus affords different responses as compared to the same responses in both tasks. These congruency effects indicate some form of application of the stimulus-response (S-R) rules of the currently irrelevant task. Between-task congruency effects are usually enhanced on task switch trials compared with task repetition trials. Here we investigate whether this interaction reflects stronger proactive interference from the irrelevant task on switch trials or whether performance on switch trials is characterized by generally enhanced susceptibility to task-irrelevant information processing. To this end, we contrasted between-task congruency effects with interference exerted from flanker stimuli taken from the current task (Experiment 1) and from spatial-numerical association of response codes (SNARC; Experiment 2). In both experiments, between-task congruency effects were larger on switch trials than on repetition trials, whereas interference from the other source remained constant, thus demonstrating that switch trials are not characterized by generally increased distractibility.

The Mismatch Negativity (MMN), a component of the event-related potential (ERP), is elicited by a deviant following a series of standard stimuli. The present study addressed the question whether two deviants occurring successively in one hierarchically organized auditory object would elicit separate MMN responses. An example of such an object is a VC syllable (vowel + consonant). In a passive oddball protocol, the syllables [ɔx] and [ɛʃ] were presented both as standards and deviants so that both phonemes, the vowel and the consonant, changed in the respective deviant. Two negative responses were found in the deviant-minus-standard difference waves. Due to the latencies these effects could not be interpreted as separate MMN responses to the phonemic changes. Instead, the first effect (108 ms) was taken as an N1 modulation whereas the second negativity (168 ms) was interpreted as an MMN mainly reflecting the change of the initial vowel. Furthermore, the present data were statistically compared with related results from Steinberg et al. (2010a, b) obtained partly from the same stimuli presented in oddball blocks with simple mono-phonemic deviances due to changing vowels. Higher MMN amplitudes were found for the syllable [ɛʃ] in the present data compared to those previous findings. Although this difference was only present for one of the stimulus syllables, it is discussed as a possible indicator of an anticipatory MMN enhancement due to the predictability of the second change in the deviant of the present experiment.

The present study examined the effect of participants' music genre preference on the neural processes underlying evaluative and cognitive judgements of music using the event-related potential technique. To this aim, two participant groups differing in their preference for Latin American and Heavy Metal music performed a liking judgement and a genre classification task on a variety of excerpts of either music genre. A late positive potential (LPP) was elicited in all conditions between 600 and 900 ms after stimulus onset. During the genre classification task, an early negativity was elicited by the preferred compared to the non-preferred music at around 230-370 ms whereas the non-preferred genre was characterized by a larger LPP. The findings suggest that evaluative and cognitive judgements of music are accompanied by affective responses and that the valence of music may spontaneously modulate early processes of music categorization even when no overt liking judgement is required.

Music is often studied as a cognitive domain alongside language. The emotional aspects of music have also been shown to be important, but views on their nature diverge. For instance, the specific emotions that music induces and how they relate to emotional expression are still under debate. Here we propose a mental and neural chronometry of the aesthetic experience of music initiated and mediated by external and internal contexts such as intentionality, background mood, attention, and expertise. The initial stages necessary for an aesthetic experience of music are feature analysis, integration across modalities, and cognitive processing on the basis of long-term knowledge. These stages are common to individuals belonging to the same musical culture. The initial emotional reactions to music include the startle reflex, core “liking,” and arousal. Subsequently, discrete emotions are perceived and induced. Presumably somatomotor processes synchronizing the body with the music also come into play here. The subsequent stages, in which cognitive, affective, and decisional processes intermingle, require controlled cross-modal neural processes to result in aesthetic emotions, aesthetic judgments, and conscious liking. These latter aesthetic stages often require attention, intentionality, and expertise for their full actualization.

Turbogeneratoren nehmen hinsichtlich der Wandlung und Übertragung elektrischer Leistung eine Schlüsselrolle in der gegenwärtigen und zukünftigen Energiewirtschaft ein. In einer zunehmend elektrifizierten Welt ist ihre Zuverlässigkeit von essenzieller Bedeutung. Die vorliegende Dissertation ist durch eine erhöhte Schadenshäufigkeit des Isoliersystems der Ständerwicklung im Bereich des Blechpaketendes solcher Turbogeneratoren motiviert. Es wird die Arbeitshypothese aufgestellt, dass lokale Heißstellen in diesem besonders betroffenen Bereich maßgeblich zu beschleunigten Alterungsprozessen des Isoliersystems beitragen. Unter Verwendung einer neu entwickelten elektromagnetischen Submodell-Methode für Simulationen mit Finiten-Elementen, werden Wirbelstromverluste in Ständerstäben infolge radial gerichteter magnetischer Endfelder berechnet. Diese Wärmequellen werden in ein thermisches FE-Modell zur Temperaturfeldberechnung übertragen, welches lokal deutlich erhöhte Temperaturen des Ständerstabes im Nutaustrittsbereich ausweist und die Arbeitshypothese bestätigt. Ferner erfolgt die Simulation verschiedener betrieblicher sowie geometrischer Einflussgrößen, wie beispielsweise die der Abtreppungsgeometrie. Der in dieser Dissertation erzielte Wissenserwerb ermöglicht eine Optimierung künftiger elektrischer Maschinen und erhöht deren Zuverlässigkeit, was sich als wertvoller Beitrag für die bevorstehende Elektrifizierung der Zukunft erweist.

The mental organization of linguistic knowledge and its involvement in speech processing can be investigated using the mismatch negativity (MMN) component of the auditory event-related potential. A contradiction arises, however, between the technical need for strict control of acoustic stimulus properties and the quest for naturalness and acoustic variability of the stimuli. Here, two methods of preparing speech stimulus material were compared. Focussing on the automatic processing of a phonotactic restriction in German, two corresponding sets of various vowel-fricative syllables were used as stimuli. The former syllables were naturally spoken while the latter ones were created by means of cross-splicing. Phonetically, natural and spliced syllables differed with respect to the appropriateness of coarticulatory information about the forthcoming fricative within the vowels. Spliced syllables containing clearly misleading phonetic information were found to elicit larger N2 responses compared to their natural counterparts. Furthermore, MMN results found for the natural syllables could not be replicated with these spliced stimuli. These findings indicate that the automatic processing of the stimuli was considerably affected by the stimulus preparation method. Thus, in spite of its unquestioned benefits for MMN experiments, the splicing technique may lead to interference effects on the linguistic factors under investigation.

Die Krankheitsausprägung berufsbedingter posttraumatischer Belastungsstörungen (PTBS) hängt im zivilen wie auch im militärischen Kontext von vielfältigen Einflussfaktoren ab. 74 Soldaten mit PTBS, die sich in der Abteilung für Psychiatrie und Psychotherapie des Bundeswehrkrankenhauses Berlin ambulant oder stationär vorstellten, wurden im Hinblick auf Zusammenhänge zwischen Gesamtschwere der PTBS zu Therapiebeginn sowie der Symptomcluster Übererregung, Vermeidungsverhalten und intrusiver Symptomatik und psychosozialen und militärspezifischen Merkmalen untersucht. Soldaten mit einsatzbedingter PTBS litten signifikant stärker unter Übererregbarkeit als Soldaten mit nicht-einsatzbedingter PTBS. Bei Soldaten in Führungsfunktionen (Stabsoffizieren) waren Intrusionen signifikant schwächer ausgeprägt als bei anderen Dienstgradgruppen. Bei Soldaten mit verzögertem Beginn der PTBS waren Gesamtschwere und Intrusionssymptomatik schwächer ausgeprägt. Diese Studie gibt erste Hinweise auf Faktoren, die eine spezifische Symptomausgestaltung der PTBS bei Soldaten beeinflussen und die in der Gestaltung therapeutischer Konzeptionen Berücksichtigung finden sollten.

In a variety of conflict paradigms, target and distractor stimuli are defined in terms of perceptual features. Interference evoked by distractor stimuli tends to be reduced when the ratio of congruent to incongruent trials is decreased, suggesting conflict-induced perceptual filtering (i.e., adjusting the processing weights assigned to stimuli associated with the target and with the distractor features). In search of evidence for such a mechanism, we administered a flanker task, in which targets and distractors were defined in terms of stimulus location (Experiment 1) or color (Experiment 2). The efficiency of processing stimuli associated with target and distractor features was assessed in intermixed trials of a visual search task, in which a target had to be detected irrespective of these features. In both experiments search times were shorter for stimuli associated with the target feature than with the distractor feature of the flanker task. This effect was increased under conditions of a reduced congruent/incongruent ratio, thereby providing evidence for conflict-dependent perceptual filtering.