Themen für Masterarbeiten

Beschreibung: The medial prefrontal cortex is very prominent in controlling a range of different cognitive processes. When it comes to the control of our behaviour, an essential key component is the intentional inhibition of actions. This project shall address the role of medial prefrontal cortex in controlling the activity level of primary motor cortex when healthy, young volunteers are either instructed to execute complex finger movements versus when they are told to actively withhold action execution. Thereby, interaction of prefrontal cortex will be investigated using EEG recordings (first MSc project) and functional near infrared spectroscopy (fNIRS) ? a method of non-invasively measuring blood oxygenation in the cortex (second MSc project).
Kontakt: Prof. Paul Sauseng, E-Mail

Beschreibung: Parallel processing of multiple items in working memory is difficult. And whenever we have a lot of information to deal with we find an increase of slow rhythmical brain activity in medial prefrontal cortex, so called frontal-midline theta activity. But what if we keep the amount of information constant but change the complexity of memory operation that needs to be carried out? Will that also result in an increase of frontal-midline theta activity?
In this study, to which one MSC candidate can be assigned, EEG will be recorded in healthy, young volunteers while they are doing a visuo-spatial working memory task. A colour code will tell the participants what they will have to do with presented visual items: simply retain them in working memory for a few seconds, rotate them horizontally or vertically, or rotate them around both axes. Frontal-midline theta activity will be obtained, and it will be investigated whether the complexity of mental operation that has to be carried out will parametrically increase theta amplitude.

Kontakt: Prof. Paul Sauseng, E-Mail

Beschreibung: Our perception, our attention and our memory are strongly determined by actions that will result from these cognitive functions. Therefore, it is assumed that action plans bias memory representations. Recently, it has been shown in a series of studies that visual working memory traces (in visual brain areas) can be supported and even shielded from interference by action plans (in cortical motor areas). Here, in young, healthy volunteers we will use transcranial magnetic stimulation over the motor cortex in an attempt to transiently ?knock out? action plans associated with visual working memory representations. We assume that this will lead to a weakening of working memory traces and particularly a higher vulnerability to interference.
One MSc candidate can be assigned to the study. A TMS experiment will be designed, implemented and carried out. Resulting behavioural working memory parameters will be obtained and analysed.

Kontakt: Prof. Paul Sauseng, E-Mail

Beschreibung: We can flexibly encode, store and process different components of visual information in working memory. Thereby, it turns out that the exact location and the specific shape of visual items are processed in different regions (even entirely different streams) of the visual system. If we focus on processing one dimension of visual information, we will have to activate the respective visual brain regions but at the same time also inhibit brain regions that are processing any other dimension of this visual information. Although it is relatively well known which brain areas are involved in these processes, the exact mechanism *how* the brain flexibly selects processing of the one or the other dimension and, thus, activates or inhibits respective brain areas is still unclear.
In this project a study will be implemented and carried out in which EEG is recorded from healthy, young volunteers while they are performing a visual working memory task (requiring the flexible processing of either location or shape of visual items). EEG will then be pre-processed and analysed.
One MSc candidate on this study can investigate amplitude of so called alpha activity in the EEG as a proxy of cortical activation/deactivation of parietal and occipital-temporal brain regions and can determine whether the ratio of activation and deactivation predicts how well participants are doing on the task.
A second MSc candidate can focus their analysis on interactions between prefrontal and visual cortical areas to find out whether and how the prefrontal cortex controls the activation level of posterior brain regions.

Kontakt: Prof. Paul Sauseng, E-Mail

Beschreibung: Neuronal communication is supposed to rely on synchronized (i.e., coherent) activity between interacting neural populations. In line with this assumption, previous studies have found increased alpha coherence between visual and motor areas during successful visuomotor integration (e.g., when participants correctly use visual feedback to adjust motor outputs). The causal relevance and driving factors of this signature, however, remain a matter of ongoing research.
Master?s theses related to this topic can be offered to 1-2 students and could investigate the causal relevance and driving factors of centro-occipital alpha coherence for visuomotor integration by applying 10 Hz transcranial magnetic stimulation (TMS) over visual and motor areas while participants perform a visuomotor task and by investigating TMS effects on electroencephalographic (EEG) centro-occipital alpha coherence and/or behavioral performance.

Literature:
[1] Hummel, F., & Gerloff, C. (2005). Larger interregional synchrony is associated with greater behavioral success in a complex sensory integration task in humans. Cerebral Cortex, 15(5), 670-678.
[2] Blum, J., Lutz, K., & Jäncke, L. (2007). Coherence and phase locking of intracerebral activation during visuo-and audio-motor learning of continuous tracking movements. Experimental brain research, 182, 59-69.
[3] Rilk, A. J., Soekadar, S. R., Sauseng, P., & Plewnia, C. (2011). Alpha coherence predicts accuracy during a visuomotor tracking task. Neuropsychologia, 49(13), 3704-3709.

Kontakt: Dr. Charline Peylo, E-Mail

Beschreibung: Top-down predictions of future events based on prior experience can help to allocate limited attentional resources more efficiently and are thought to be implemented as mental templates stored in memory. Previous research suggests that the reactivation of a mental template into working memory in anticipation of a corresponding task-relevant event is supported by increased fronto-parietal theta coherence and that the matching process between such a memory template and the bottom-up sensory information is reflected by increased theta-gamma coupling in early visual areas shortly after. Evidence for this model of memory matching in visual perception, however, has remained correlative so far.
Master?s theses related to this topic can be offered to 1-2 students and could investigate the causal relevance of fronto-parietal theta coherence and/or parieto-occipital theta-gamma coupling by applying transcranial magnetic stimulation (TMS) over frontal areas and/or parieto-occipital areas to interrupt template reactivation and/or matching processes, respectively, and by investigating the effects of TMS stimulation on electroencephalographic (EEG) fronto-parietal theta coherence, parieto-occipital theta-gamma coupling and/or behavioral performance in a template-guided visual search task.

Literature:
[1] Sauseng, P., Klimesch, W., Gruber, W. R., & Birbaumer, N. (2008). Cross-frequency phase synchronization: a brain mechanism of memory matching and attention. Neuroimage, 40(1), 308-317.
[2] Holz, E. M., Glennon, M., Prendergast, K., & Sauseng, P. (2010). Theta?gamma phase synchronization during memory matching in visual working memory. Neuroimage, 52(1), 326-335.
[3] Sauseng, P., Griesmayr, B., Freunberger, R., & Klimesch, W. (2010). Control mechanisms in working memory: a possible function of EEG theta oscillations. Neuroscience & Biobehavioral Reviews, 34(7), 1015-1022.
[4] Sauseng, P., Conci, M., Wild, B., & Geyer, T. (2015). Predictive coding in visual search as revealed by cross-frequency EEG phase synchronization. Frontiers in Psychology, 6, 1655.
[5] Peylo, C., Friedrich, E. V., Minarik, T., Biel, A. L., & Sauseng, P. (2022). Theta:gamma phase coupling and evoked gamma activity reflect the fidelity of mental templates during memory matching in visual perception. Cerebral Cortex, 32(19), 4156-4171.

Kontakt: Dr. Charline Peylo, E-Mail

Beschreibung: These MSc projects should be connected with an internship in the lab; and they mainly include the preprocessing and analysis of EEG data.
In a first study, we could show that slow rhythmical brain activity in the dorsomedial prefrontal cortex controls distributed networks associated with working memory as well as mentalizing during cognitively demanding visual and social tasks. Depending on the effort necessary for cognitive operations, the phase of slow frontal oscillations is used to precisely tune communication with posterior brain areas. For participants having low autistic personality traits, this mechanism is identical across tasks ? no matter whether visual or social information is processed. Participants with high autistic personality traits ? thus, with difficulty in social cognition ? however, have an inability to efficiently tune brain communication depending on cognitive effort in visual information processing. Even more striking, in higher social cognition they fail to implement coordination of distributed brain networks by slow frontal oscillations completely.
In a second study, we used the same experimental design including the visual and social working memory task and combined our EEG recordings with transcranial magnetic stimulation (TMS). We recorded each participant twice and inhibited either the Dorsomedial Prefrontal Cortex (DMPFC) or the vertex as control site. If the DMPFC is a key region in controlling working memory and social cognition, and if a malfunction of associated rhythmic brain processes are linked to autistic personality traits, TMS over the DMPFC in participants with low autistic personality traits should lead to similar EEG activation patterns as were observed in high autistic personality trait volunteers without any TMS. The already recorded EEG data should be preprocessed and analyzed with commercial EEG signal analysis software and customized Matlab scripts (all under supervision).
2 MSc students can be assigned to this project.

Kontakt: Dr. Elisabeth Friedrich-Higgs, E-Mail