@misc{GebelBuschStelzeletal.2022,
  author    = {Gebel, Arnd and Busch, Aglaja and Stelzel, Christine and Hortob{\´a}gyi, Tibor and Granacher, Urs},
  title     = {Effects of Physical and Mental Fatigue on Postural Sway and Cortical Activity in Healthy Young Adults},
  series = {Zweitver{\"o}ffentlichungen der Universit{\"a}t Potsdam : Humanwissenschaftliche Reihe},
  journal   = {Zweitver{\"o}ffentlichungen der Universit{\"a}t Potsdam : Humanwissenschaftliche Reihe},
  publisher = {Universit{\"a}tsverlag Potsdam},
  address   = {Potsdam},
  issn      = {1866-8364},
  doi       = {10.25932/publishup-56441},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-564419},
  pages     = {1 -- 14},
  year      = {2022},
  abstract  = {Physical fatigue (PF) negatively affects postural control, resulting in impaired balance performance in young and older adults. Similar effects on postural control can be observed for mental fatigue (MF) mainly in older adults. Controversial results exist for young adults. There is a void in the literature on the effects of fatigue on balance and cortical activity. Therefore, this study aimed to examine the acute effects of PF and MF on postural sway and cortical activity. Fifteen healthy young adults aged 28 ± 3 years participated in this study. MF and PF protocols comprising of an all-out repeated sit-to-stand task and a computer-based attention network test, respectively, were applied in random order. Pre and post fatigue, cortical activity and postural sway (i.e., center of pressure displacements [CoPd], velocity [CoPv], and CoP variability [CV CoPd, CV CoPv]) were tested during a challenging bipedal balance board task. Absolute spectral power was calculated for theta (4-7.5 Hz), alpha-2 (10.5-12.5 Hz), beta-1 (13-18 Hz), and beta-2 (18.5-25 Hz) in frontal, central, and parietal regions of interest (ROI) and baseline-normalized. Inference statistics revealed a significant time-by-fatigue interaction for CoPd (p = 0.009, d = 0.39, Δ 9.2\%) and CoPv (p = 0.009, d = 0.36, Δ 9.2\%), and a significant main effect of time for CoP variability (CV CoPd: p = 0.001, d = 0.84; CV CoPv: p = 0.05, d = 0.62). Post hoc analyses showed a significant increase in CoPd (p = 0.002, d = 1.03) and CoPv (p = 0.003, d = 1.03) following PF but not MF. For cortical activity, a significant time-by-fatigue interaction was found for relative alpha-2 power in parietal (p < 0.001, d = 0.06) areas. Post hoc tests indicated larger alpha-2 power increases after PF (p < 0.001, d = 1.69, Δ 3.9\%) compared to MF (p = 0.001, d = 1.03, Δ 2.5\%). In addition, changes in parietal alpha-2 power and measures of postural sway did not correlate significantly, irrespective of the applied fatigue protocol. No significant changes were found for the other frequency bands, irrespective of the fatigue protocol and ROI under investigation. Thus, the applied PF protocol resulted in increased postural sway (CoPd and CoPv) and CoP variability accompanied by enhanced alpha-2 power in the parietal ROI while MF led to increased CoP variability and alpha-2 power in our sample of young adults. Potential underlying cortical mechanisms responsible for the greater increase in parietal alpha-2 power after PF were discussed but could not be clearly identified as cause. Therefore, further future research is needed to decipher alternative interpretations.},
  language  = {en}
}
@phdthesis{VenturaBort2020,
  author    = {Ventura-Bort, Carlos},
  title     = {Temporo-spatial dynamics of the impact of emotional contexts on visual processing and memory},
  doi       = {10.25932/publishup-55023},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-550236},
  school      = {Universit{\"a}t Potsdam},
  pages     = {208},
  year      = {2020},
  abstract  = {It has frequently been observed that single emotional events are not only more efficiently processed, but also better remembered, and form longer-lasting memory traces than neutral material. However, when emotional information is perceived as a part of a complex event, such as in the context of or in relation to other events and/or source details, the modulatory effects of emotion are less clear. The present work aims to investigate how emotional, contextual source information modulates the initial encoding and subsequent long-term retrieval of associated neutral material (item memory) and contextual source details (contextual source memory). To do so, a two-task experiment was used, consisting of an incidental encoding task in which neutral objects were displayed over different contextual background scenes which varied in emotional content (unpleasant, pleasant, and neutral), and a delayed retrieval task (1 week), in which previously-encoded objects and new ones were presented. In a series of studies, behavioral indices (Studies 2, 3, and 5), event-related potentials (ERPs; Studies 1-4), and functional magnetic resonance imaging (Study 5) were used to investigate whether emotional contexts can rapidly tune the visual processing of associated neutral information (Study 1) and modulate long-term item memory (Study 2), how different recognition memory processes (familiarity vs. recollection) contribute to these emotion effects on item and contextual source memory (Study 3), whether the emotional effects of item memory can also be observed during spontaneous retrieval (Sstudy 4), and which brain regions underpin the modulatory effects of emotional contexts on item and contextual source memory (Study 5). In Study 1, it was observed that emotional contexts by means of emotional associative learning, can rapidly alter the processing of associated neutral information. Neutral items associated with emotional contexts (i.e. emotional associates) compared to neutral ones, showed enhanced perceptual and more elaborate processing after one single pairing, as indexed by larger amplitudes in the P100 and LPP components, respectively. Study 2 showed that emotional contexts produce longer-lasting memory effects, as evidenced by better item memory performance and larger ERP Old/New differences for emotional associates. In Study 3, a mnemonic differentiation was observed between item and contextual source memory which was modulated by emotion. Item memory was driven by familiarity, independently of emotional contexts during encoding, whereas contextual source memory was driven by recollection, and better for emotional material. As in Study 2, enhancing effects of emotional contexts for item memory were observed in ERPs associated with recollection processes. Likewise, for contextual source memory, a pronounced recollection-related ERP enhancement was observed for exclusively emotional contexts. Study 4 showed that the long-term recollection enhancement of emotional contexts on item memory can be observed even when retrieval is not explicitly attempted, as measured with ERPs, suggesting that the emotion enhancing effects on memory are not related to the task embedded during recognition, but to the motivational relevance of the triggering event. In Study 5, it was observed that enhancing effects of emotional contexts on item and contextual source memory involve stronger engagement of the brain's regions which are associated with memory recollection, including areas of the medial temporal lobe, posterior parietal cortex, and prefrontal cortex. Taken together, these findings suggest that emotional contexts rapidly modulate the initial processing of associated neutral information and the subsequent, long-term item and contextual source memories. The enhanced memory effects of emotional contexts are strongly supported by recollection rather than familiarity processes, and are shown to be triggered when retrieval is both explicitly and spontaneously attempted. These results provide new insights into the modulatory role of emotional information on the visual processing and the long-term recognition memory of complex events. The present findings are integrated into the current theoretical models and future ventures are discussed.},
  language  = {en}
}
@misc{JeglinskiMendeSchmidt2021,
  author    = {Jeglinski-Mende, Melinda A. and Schmidt, Hendrikje},
  title     = {Psychotherapy in the Framework of Embodied Cognition},
  series = {Postprints der Universit{\"a}t Potsdam : Humanwissenschaftliche Reihe},
  journal   = {Postprints der Universit{\"a}t Potsdam : Humanwissenschaftliche Reihe},
  number    = {708},
  issn      = {1866-8364},
  doi       = {10.25932/publishup-50316},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-503162},
  pages     = {11},
  year      = {2021},
  abstract  = {Mental health problems remain among the main generators of costs within and beyond the health care system. Psychotherapy, the tool of choice in their treatment, is qualified by social interaction, and cooperation within the therapist-patient-dyad. Research into the factors influencing therapy success to date is neither exhaustive nor conclusive. Among many others, the quality of the relationship between therapist and patient stands out regardless of the followed psychotherapy school. Emerging research points to a connection between interpersonal synchronization within the sessions and therapy outcome. Consequently, it can be considered significant for the shaping of this relationship. The framework of Embodied Cognition assumes bodily and neuronal correlates of thinking. Therefore, the present paper reviews investigations on interpersonal, non-verbal synchrony in two domains: firstly, studies on interpersonal synchrony in psychotherapy are reviewed (synchronization of movement). Secondly, findings on neurological correlates of interpersonal synchrony (assessed with EEG, fMRI, fNIRS) are summarized in a narrative manner. In addition, the question is asked whether interpersonal synchrony can be achieved voluntarily on an individual level. It is concluded that there might be mechanisms which could give more insights into therapy success, but as of yet remain uninvestigated. Further, the framework of embodied cognition applies more to the current body of evidence than classical cognitivist views. Nevertheless, deeper research into interpersonal physical and neurological processes utilizing the framework of Embodied Cognition emerges as a possible route of investigation on the road to lower drop-out rates, improved and quality-controlled therapeutic interventions, thereby significantly reducing healthcare costs.},
  language  = {en}
}
@misc{BridwellCavanaghCollinsetal.2018,
  author    = {Bridwell, David A. and Cavanagh, James F. and Collins, Anne G. E. and Nunez, Michael D. and Srinivasan, Ramesh and Stober, Sebastian and Calhoun, Vince D.},
  title     = {Moving beyond ERP components},
  series = {Postprints der Universit{\"a}t Potsdam : Humanwissenschaftliche Reihe},
  journal   = {Postprints der Universit{\"a}t Potsdam : Humanwissenschaftliche Reihe},
  number    = {656},
  issn      = {1866-8364},
  doi       = {10.25932/publishup-45966},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-459667},
  pages     = {19},
  year      = {2018},
  abstract  = {Relationships between neuroimaging measures and behavior provide important clues about brain function and cognition in healthy and clinical populations. While electroencephalography (EEG) provides a portable, low cost measure of brain dynamics, it has been somewhat underrepresented in the emerging field of model-based inference. We seek to address this gap in this article by highlighting the utility of linking EEG and behavior, with an emphasis on approaches for EEG analysis that move beyond focusing on peaks or "components" derived from averaging EEG responses across trials and subjects (generating the event-related potential, ERP). First, we review methods for deriving features from EEG in order to enhance the signal within single-trials. These methods include filtering based on user-defined features (i.e., frequency decomposition, time-frequency decomposition), filtering based on data-driven properties (i.e., blind source separation, BSS), and generating more abstract representations of data (e.g., using deep learning). We then review cognitive models which extract latent variables from experimental tasks, including the drift diffusion model (DDM) and reinforcement learning (RL) approaches. Next, we discuss ways to access associations among these measures, including statistical models, data-driven joint models and cognitive joint modeling using hierarchical Bayesian models (HBMs). We think that these methodological tools are likely to contribute to theoretical advancements, and will help inform our understandings of brain dynamics that contribute to moment-to-moment cognitive function.},
  language  = {en}
}
@misc{AgarwalMarwanMaheswaranetal.2017,
  author    = {Agarwal, Ankit and Marwan, Norbert and Maheswaran, Rathinasamy and Merz, Bruno and Kurths, J{\"u}rgen},
  title     = {Multi-scale event synchronization analysis for unravelling climate processes},
  series = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe},
  journal   = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe},
  number    = {661},
  issn      = {1866-8372},
  doi       = {10.25932/publishup-41827},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-418274},
  pages     = {13},
  year      = {2017},
  abstract  = {The temporal dynamics of climate processes are spread across different timescales and, as such, the study of these processes at only one selected timescale might not reveal the complete mechanisms and interactions within and between the (sub-) processes. To capture the non-linear interactions between climatic events, the method of event synchronization has found increasing attention recently. The main drawback with the present estimation of event synchronization is its restriction to analysing the time series at one reference timescale only. The study of event synchronization at multiple scales would be of great interest to comprehend the dynamics of the investigated climate processes. In this paper, the wavelet-based multi-scale event synchronization (MSES) method is proposed by combining the wavelet transform and event synchronization. Wavelets are used extensively to comprehend multi-scale processes and the dynamics of processes across various timescales. The proposed method allows the study of spatio-temporal patterns across different timescales. The method is tested on synthetic and real-world time series in order to check its replicability and applicability. The results indicate that MSES is able to capture relationships that exist between processes at different timescales.},
  language  = {en}
}
@misc{VenturaBortWirknerGenheimeretal.2018,
  author    = {Ventura-Bort, Carlos and Wirkner, Janine and Genheimer, Hannah and Wendt, Julia and Hamm, Alfons O. and Weymar, Mathias},
  title     = {Effects of Transcutaneous Vagus Nerve Stimulation (tVNS) on the P300 and Alpha-Amylase Level},
  series = {Postprints der Universit{\"a}t Potsdam : Humanwissenschaftliche Reihe},
  journal   = {Postprints der Universit{\"a}t Potsdam : Humanwissenschaftliche Reihe},
  number    = {473},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-419259},
  pages     = {12},
  year      = {2018},
  abstract  = {Recent research suggests that the P3b may be closely related to the activation of the locus coeruleus-norepinephrine (LC-NE) system. To further study the potential association, we applied a novel technique, the non-invasive transcutaneous vagus nerve stimulation (tVNS), which is speculated to increase noradrenaline levels. Using a within-subject cross-over design, 20 healthy participants received continuous tVNS and sham stimulation on two consecutive days (stimulation counterbalanced across participants) while performing a visual oddball task. During stimulation, oval non-targets (standard), normal-head (easy) and rotated-head (difficult) targets, as well as novel stimuli (scenes) were presented. As an indirect marker of noradrenergic activation we also collected salivary alpha-amylase (sAA) before and after stimulation. Results showed larger P3b amplitudes for target, relative to standard stimuli, irrespective of stimulation condition. Exploratory post hoc analyses, however, revealed that, in comparison to standard stimuli, easy (but not difficult) targets produced larger P3b (but not P3a) amplitudes during active tVNS, compared to sham stimulation. For sAA levels, although main analyses did not show differential effects of stimulation, direct testing revealed that tVNS (but not sham stimulation) increased sAA levels after stimulation. Additionally, larger differences between tVNS and sham stimulation in P3b magnitudes for easy targets were associated with larger increase in sAA levels after tVNS, but not after sham stimulation. Despite preliminary evidence for a modulatory influence of tVNS on the P3b, which may be partly mediated by activation of the noradrenergic system, additional research in this field is clearly warranted. Future studies need to clarify whether tVNS also facilitates other processes, such as learning and memory, and whether tVNS can be used as therapeutic tool.},
  language  = {en}
}
@phdthesis{BreakellFernandez2016,
  author    = {Breakell Fernandez, Leigh},
  title     = {Investigating word order processing using pupillometry and event-related potentials},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-91438},
  school      = {Universit{\"a}t Potsdam},
  pages     = {x, 122},
  year      = {2016},
  abstract  = {In this thesis sentence processing was investigated using a psychophysiological measure known as pupillometry as well as Event-Related Potentials (ERP). The scope of the the- sis was broad, investigating the processing of several different movement constructions with native speakers of English and second language learners of English, as well as word order and case marking in German speaking adults and children. Pupillometry and ERP allowed us to test competing linguistic theories and use novel methodologies to investigate the processing of word order. In doing so we also aimed to establish pupillometry as an effective way to investigate the processing of word order thus broadening the methodological spectrum.},
  language  = {en}
}
@phdthesis{Metzner2015,
  author    = {Metzner, Paul-Philipp},
  title     = {Eye movements and brain responses in natural reading},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-82806},
  school      = {Universit{\"a}t Potsdam},
  pages     = {xv, 160},
  year      = {2015},
  abstract  = {Intuitively, it is clear that neural processes and eye movements in reading are closely connected, but only few studies have investigated both signals simultaneously. Instead, the usual approach is to record them in separate experiments and to subsequently consolidate the results. However, studies using this approach have shown that it is feasible to coregister eye movements and EEG in natural reading and contributed greatly to the understanding of oculomotor processes in reading. The present thesis builds upon that work, assessing to what extent coregistration can be helpful for sentence processing research. In the first study, we explore how well coregistration is suited to study subtle effects common to psycholinguistic experiments by investigating the effect of distance on dependency resolution. The results demonstrate that researchers must improve the signal-to-noise ratio to uncover more subdued effects in coregistration. In the second study, we compare oscillatory responses in different presentation modes. Using robust effects from world knowledge violations, we show that the generation and retrieval of memory traces may differ between natural reading and word-by-word presentation. In the third study, we bridge the gap between our knowledge of behavioral and neural responses to integration difficulties in reading by analyzing the EEG in the context of regressive saccades. We find the P600, a neural indicator of recovery processes, when readers make a regressive saccade in response to integration difficulties. The results in the present thesis demonstrate that coregistration can be a useful tool for the study of sentence processing. However, they also show that it may not be suitable for some questions, especially if they involve subtle effects.},
  language  = {en}
}
@book{Dambacher2010,
  author    = {Dambacher, Michael},
  title     = {Bottom-up and top-down processes in reading : influences of frequency and predictability on event-related potentials and eye movements},
  publisher = {Universit{\"a}tsverlag Potsdam},
  address   = {Potsdam},
  isbn      = {978-3-86956-059-5},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-42024},
  publisher      = {Universit{\"a}t Potsdam},
  pages     = {239},
  year      = {2010},
  abstract  = {In reading, word frequency is commonly regarded as the major bottom-up determinant for the speed of lexical access. Moreover, language processing depends on top-down information, such as the predictability of a word from a previous context. Yet, however, the exact role of top-down predictions in visual word recognition is poorly understood: They may rapidly affect lexical processes, or alternatively, influence only late post-lexical stages. To add evidence about the nature of top-down processes and their relation to bottom-up information in the timeline of word recognition, we examined influences of frequency and predictability on event-related potentials (ERPs) in several sentence reading studies. The results were related to eye movements from natural reading as well as to models of word recognition. As a first and major finding, interactions of frequency and predictability on ERP amplitudes consistently revealed top-down influences on lexical levels of word processing (Chapters 2 and 4). Second, frequency and predictability mediated relations between N400 amplitudes and fixation durations, pointing to their sensitivity to a common stage of word recognition; further, larger N400 amplitudes entailed longer fixation durations on the next word, a result providing evidence for ongoing processing beyond a fixation (Chapter 3). Third, influences of presentation rate on ERP frequency and predictability effects demonstrated that the time available for word processing critically co-determines the course of bottom-up and top-down influences (Chapter 4). Fourth, at a near-normal reading speed, an early predictability effect suggested the rapid comparison of top-down hypotheses with the actual visual input (Chapter 5). The present results are compatible with interactive models of word recognition assuming that early lexical processes depend on the concerted impact of bottom-up and top-down information. We offered a framework that reconciles the findings on a timeline of word recognition taking into account influences of frequency, predictability, and presentation rate (Chapter 4).},
  language  = {en}
}
@phdthesis{Dornhege2006,
  author    = {Dornhege, Guido},
  title     = {Increasing information transfer rates for brain-computer interfacing},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-7690},
  school      = {Universit{\"a}t Potsdam},
  year      = {2006},
  abstract  = {The goal of a Brain-Computer Interface (BCI) consists of the development of a unidirectional interface between a human and a computer to allow control of a device only via brain signals. While the BCI systems of almost all other groups require the user to be trained over several weeks or even months, the group of Prof. Dr. Klaus-Robert M{\"u}ller in Berlin and Potsdam, which I belong to, was one of the first research groups in this field which used machine learning techniques on a large scale. The adaptivity of the processing system to the individual brain patterns of the subject confers huge advantages for the user. Thus BCI research is considered a hot topic in machine learning and computer science. It requires interdisciplinary cooperation between disparate fields such as neuroscience, since only by combining machine learning and signal processing techniques based on neurophysiological knowledge will the largest progress be made. In this work I particularly deal with my part of this project, which lies mainly in the area of computer science. I have considered the following three main points: <b>Establishing a performance measure based on information theory:</b> I have critically illuminated the assumptions of Shannon's information transfer rate for application in a BCI context. By establishing suitable coding strategies I was able to show that this theoretical measure approximates quite well to what is practically achieveable. <b>Transfer and development of suitable signal processing and machine learning techniques:</b> One substantial component of my work was to develop several machine learning and signal processing algorithms to improve the efficiency of a BCI. Based on the neurophysiological knowledge that several independent EEG features can be observed for some mental states, I have developed a method for combining different and maybe independent features which improved performance. In some cases the performance of the combination algorithm outperforms the best single performance by more than 50 \%. Furthermore, I have theoretically and practically addressed via the development of suitable algorithms the question of the optimal number of classes which should be used for a BCI. It transpired that with BCI performances reported so far, three or four different mental states are optimal. For another extension I have combined ideas from signal processing with those of machine learning since a high gain can be achieved if the temporal filtering, i.e., the choice of frequency bands, is automatically adapted to each subject individually. <b>Implementation of the Berlin brain computer interface and realization of suitable experiments:</b> Finally a further substantial component of my work was to realize an online BCI system which includes the developed methods, but is also flexible enough to allow the simple realization of new algorithms and ideas. So far, bitrates of up to 40 bits per minute have been achieved with this system by absolutely untrained users which, compared to results of other groups, is highly successful.},
  subject      = {Kybernetik},
  language  = {en}
}