TY  - JOUR
A1  - Dornhege, Guido
A1  - Blankertz, Benjamin
A1  - Krauledat, Matthias
A1  - Losch, Florian
A1  - Curio, Gabriel
A1  - Müller, Klaus-Robert
T1  - Combined optimization of spatial and temporal filters for improving brain-computer interfacing
JF  - IEEE transactions on bio-medical electronics
N2  - Brain-computer interface (BCI) systems create a novel communication channel from the brain to an output de ice by bypassing conventional motor output pathways of nerves and muscles. Therefore they could provide a new communication and control option for paralyzed patients. Modern BCI technology is essentially based on techniques for the classification of single-trial brain signals. Here we present a novel technique that allows the simultaneous optimization of a spatial and a spectral filter enhancing discriminability rates of multichannel EEG single-trials. The evaluation of 60 experiments involving 22 different subjects demonstrates the significant superiority of the proposed algorithm over to its classical counterpart: the median classification error rate was decreased by 11%. Apart from the enhanced classification, the spatial and/or the spectral filter that are determined by the algorithm can also be used for further analysis of the data, e.g., for source localization of the respective brain rhythms.
KW  - brain-computer interface
KW  - common spatial patterns
KW  - EEG
KW  - event-related desynchronization
KW  - single-trial-analysis
Y1  - 2006
U6  - https://doi.org/10.1109/TBME.2006.883649
SN  - 0018-9294
VL  - 53
IS  - 11
SP  - 2274
EP  - 2281
PB  - IEEE
CY  - New York
ER  - 
TY  - JOUR
A1  - Dimigen, Olaf
A1  - Sommer, Werner
A1  - Hohlfeld, Annette
A1  - Jacobs, Arthur M.
A1  - Kliegl, Reinhold
T1  - Coregistration of eye movements and EEG in natural reading analyses and review
JF  - Journal of experimental psychology : General
N2  - Brain-electric correlates of reading have traditionally been studied with word-by-word presentation, a condition that eliminates important aspects of the normal reading process and precludes direct comparisons between neural activity and oculomotor behavior. In the present study, we investigated effects of word predictability on eye movements (EM) and fixation-related brain potentials (FRPs) during natural sentence reading. Electroencephalogram (EEG) and EM (via video-based eye tracking) were recorded simultaneously while subjects read heterogeneous German sentences, moving their eyes freely over the text. FRPs were time-locked to first-pass reading fixations and analyzed according to the cloze probability of the currently fixated word. We replicated robust effects of word predictability on EMs and the N400 component in FRPs. The data were then used to model the relation among fixation duration, gaze duration, and N400 amplitude, and to trace the time course of EEG effects relative to effects in EM behavior. In an extended Methodological Discussion section, we review 4 technical and data-analytical problems that need to be addressed when FRPs are recorded in free-viewing situations (such as reading, visual search, or scene perception) and propose solutions. Results suggest that EEG recordings during normal vision are feasible and useful to consolidate findings from EEG and eye-tracking studies.
KW  - EEG
KW  - eye tracking
KW  - fixation-related potentials
KW  - artifact correction
KW  - natural viewing
Y1  - 2011
U6  - https://doi.org/10.1037/a0023885
SN  - 0096-3445
VL  - 140
IS  - 4
SP  - 552
EP  - 572
PB  - American Psychological Association
CY  - Washington
ER  - 
TY  - JOUR
A1  - Dimigen, Olaf
A1  - Kliegl, Reinhold
A1  - Sommer, Werner
T1  - Trans-saccadic parafoveal preview benefits in fluent reading: A study with fixation-related brain potentials
JF  - NeuroImage : a journal of brain function
N2  - During natural reading, a parafoveal preview of the upcoming word facilitates its subsequent recognition (e.g., shorter fixation durations compared to masked preview) but nothing is known about the neural correlates of this so-called preview benefit. Furthermore, while the evidence is strong that readers preprocess orthographic features of upcoming words, it is controversial whether word meaning can also be accessed parafoveally. We investigated the timing, scope, and electrophysiological correlates of parafoveal information use in reading by simultaneously recording eye movements and fixation-related brain potentials (FRPs) while participants read word lists fluently from left to right. For one word the target (e.g., "blade") parafoveal information was manipulated by showing an identical ("blade"), semantically related ("knife"), or unrelated ("sugar") word as preview. In boundary trials, the preview was shown parafoveally but changed to the correct target word during the incoming saccade. Replicating classic findings, target words were fixated shorter after identical previews. In the EEG, this benefit was reflected in an occipitotemporal preview positivity between 200 and 280 ms. In contrast, there was no facilitation from related previews. In parafoveal-on-foveal trials, preview and target were embedded at neighboring list positions without a display change. Consecutive fixation of two related words produced N400 priming effects, but only shortly (160 ms) after the second word was directly fixated. Results demonstrate that neural responses to words are substantially altered by parafoveal preprocessing under normal reading conditions. We found no evidence that word meaning contributes to these effects. Saccade-contingent display manipulations can be combined with EEG recordings to study extrafoveal perception in vision.
KW  - EEG
KW  - Eye tracking
KW  - Active vision
KW  - Eye-fixation-related potentials (EFRP)
KW  - Parafoveal vision
KW  - Boundary technique
Y1  - 2012
U6  - https://doi.org/10.1016/j.neuroimage.2012.04.006
SN  - 1053-8119
SN  - 1095-9572
VL  - 62
IS  - 1
SP  - 381
EP  - 393
PB  - Elsevier
CY  - San Diego
ER  - 
TY  - JOUR
A1  - Kühnpast, Nicole
A1  - Gramann, Klaus
A1  - Pollatos, Olga
T1  - Electrophysiologic evidence for multilevel deficits in emotional face processing in patients with Bulimia Nervosa
JF  - Psychosomatic medicine
N2  - Background: Empirical evidence suggests substantial deficits regarding emotion recognition in bulimia nervosa (BN). The aim of the current study was to investigate electrophysiologic evidence for deficits in emotional face processing in patients with BN. Methods: Event-related potentials were recorded from 13 women with BN and 13 matched healthy controls while viewing neutral, happy, fearful, and angry facial expressions. Participants' recognition performance for emotional faces was tested in a subsequent categorization task. In addition, the degree of alexithymia, depression, and anxiety were assessed via questionnaires. Results: Categorization of emotional faces was hampered in BN (p = .01). Amplitudes of event-related potentials differed during emotional face processing: face-specific N170 amplitudes were less pronounced for angry faces in patients with BN (mean [M] [standard deviation {SD}] = 1.46 [0.56] mu V versus M [SD] = -1.23 [0.61] mu V, p = .02). In contrast, P3 amplitudes were more pronounced in patients with BN as compared with controls (M [SD] = 2.64 [0.46] mu V versus M [SD] = 1.25 [0.39] mu V, p = .04), independent of emotional expression. Conclusions: The study provides novel electrophysiologic data showing that emotional faces are processed differently in patients with BN as compared with healthy controls. We suggest that deficits in early automatic emotion classification in BN are followed by an increased allocation of attentional resources to compensate for those deficits. These findings might contribute to a better understanding of the impaired social functioning in BN.
KW  - eating disorders
KW  - bulimia nervosa
KW  - EEG
KW  - emotions
KW  - face recognition
KW  - N170
KW  - N2
KW  - P3
Y1  - 2012
U6  - https://doi.org/10.1097/PSY.0b013e31825ca15a
SN  - 0033-3174
VL  - 74
IS  - 7
SP  - 736
EP  - 744
PB  - Lippincott Williams & Wilkins
CY  - Philadelphia
ER  - 
TY  - JOUR
A1  - McLoughlin, Grainne
A1  - Palmer, Jason
A1  - Makeig, Scott
A1  - Bigdely-Shamlo, Nima
A1  - Banaschewski, Tobias
A1  - Laucht, Manfred
A1  - Brandeis, D.
T1  - EEG Source Imaging Indices of Cognitive Control Show Associations with Dopamine System Genes
JF  - Brain Topography
N2  - Cognitive or executive control is a critical mental ability, an important marker of mental illness, and among the most heritable of neurocognitive traits. Two candidate genes, catechol-O-methyltransferase (COMT) and DRD4, which both have a roles in the regulation of cortical dopamine, have been consistently associated with cognitive control. Here, we predicted that individuals with the COMT Met/Met allele would show improved response execution and inhibition as indexed by event-related potentials in a Go/NoGo task, while individuals with the DRD4 7-repeat allele would show impaired brain activity. We used independent component analysis (ICA) to separate brain source processes contributing to high-density EEG scalp signals recorded during the task. As expected, individuals with the DRD4 7-repeat polymorphism had reduced parietal P3 source and scalp responses to response (Go) compared to those without the 7-repeat. Contrary to our expectation, the COMT homozygous Met allele was associated with a smaller frontal P3 source and scalp response to response-inhibition (NoGo) stimuli, suggesting that while more dopamine in frontal cortical areas has advantages in some tasks, it may also compromise response inhibition function. An interaction effect emerged for P3 source responses to Go stimuli. These were reduced in those with both the 7-repeat DRD4 allele and either the COMT Val/Val or the Met/Met homozygous polymorphisms but not in those with the heterozygous Val/Met polymorphism. This epistatic interaction between DRD4 and COMT replicates findings that too little or too much dopamine impairs cognitive control. The anatomic and functional separated maximally independent cortical EEG sources proved more informative than scalp channel measures for genetic studies of brain function and thus better elucidate the complex mechanisms in psychiatric illness.
KW  - EEG
KW  - Genetics
KW  - DRD4
KW  - COMT
KW  - ICA
KW  - Measure projection
Y1  - 2017
U6  - https://doi.org/10.1007/s10548-017-0601-z
SN  - 0896-0267
SN  - 1573-6792
VL  - 31
IS  - 3
SP  - 392
EP  - 406
PB  - Springer
CY  - Dordrecht
ER  - 
TY  - JOUR
A1  - Bosch, Sina
A1  - Krause, Helena
A1  - Leminen, Alina
T1  - The time-course of morphosyntactic and semantic priming in late bilinguals: A study of German adjectives
JF  - Bilingualism : language and cognition.
N2  - How do late proficient bilinguals process morphosyntactic and lexical-semantic information in their non-native language (L2)? How is this information represented in the L2 mental lexicon? And what are the neural signatures of L2 morphosyntactic and lexical-semantic processing? We addressed these questions in one behavioral and two ERP priming experiments on inflected German adjectives testing a group of advanced late Russian learners of German in comparison to native speaker (L1) controls. While in the behavioral experiment, the L2 learners performed native-like, the ERP data revealed clear L1/L2 differences with respect to the temporal dynamics of grammatical processing. Specifically, our results show that L2 morphosyntactic processing yielded temporally and spatially extended brain responses relative to L1 processing, indicating that grammatical processing of inflected words in an L2 is more demanding and less automatic than in the L1. However, this group of advanced L2 learners showed native-like lexical-semantic processing.
KW  - Inflection
KW  - EEG
KW  - Grammatical Processing
KW  - Mental Lexicon
Y1  - 2017
U6  - https://doi.org/10.1017/S1366728916000055
SN  - 1366-7289
SN  - 1469-1841
VL  - 20
SP  - 435
EP  - 456
PB  - Cambridge Univ. Press
CY  - New York
ER  - 
TY  - JOUR
A1  - Fargier, Raphael
A1  - Bürki-Foschini, Audrey Damaris
A1  - Pinet, Svetlana
A1  - Alario, F. -Xavier
A1  - Laganaro, Marina
T1  - Word onset phonetic properties and motor artifacts in speech production EEG recordings
JF  - Psychophysiology : journal of the Society for Psychophysiological Research
N2  - Electrophysiological research using verbal response paradigms faces the problem of muscle artifacts that occur during speech production or in the period preceding articulation. In this context, this paper has two related aims. The first is to show how the nature of the first phoneme influences the alignment of the ERPs. The second is to further characterize the EEG signal around the onset of articulation, both in temporal and frequency domains. Participants were asked to name aloud pictures of common objects. We applied microstate analyses and time-frequency transformations of ERPs locked to vocal onset to compare the EEG signal between voiced and unvoiced labial plosive word onset consonants. We found a delay of about 40 ms in the set of stable topographic patterns for /b/ relative to /p/ onset words. A similar shift was observed in the power increase of gamma oscillations (30-50 Hz), which had an earlier onset for /p/ trials (similar to 150 ms before vocal onset). This 40-ms shift is consistent with the length of the voiced proportion of the acoustic signal prior to the release of the closure in the vocal responses. These results demonstrate that phonetic features are an important parameter affecting response-locked ERPs, and hence that the onset of the acoustic energy may not be an optimal trigger for synchronizing the EEG activity to the response in vocal paradigms. The indexes explored in this study provide a step forward in the characterization of muscle-related artifacts in electrophysiological studies of speech and language production.
KW  - EEG
KW  - motor artifact
KW  - phonetics
KW  - picture naming
KW  - speech production
Y1  - 2017
U6  - https://doi.org/10.1111/psyp.12982
SN  - 0048-5772
SN  - 1469-8986
VL  - 55
IS  - 2
PB  - Wiley
CY  - Hoboken
ER  - 
TY  - JOUR
A1  - Bridwell, David A.
A1  - Cavanagh, James F.
A1  - Collins, Anne G. E.
A1  - Nunez, Michael D.
A1  - Srinivasan, Ramesh
A1  - Stober, Sebastian
A1  - Calhoun, Vince D.
T1  - Moving Beyond ERP Components
BT  - a selective review of approaches to integrate EEG and behavior
JF  - Frontiers in human neuroscienc
N2  - 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.
KW  - EEG
KW  - ERP
KW  - blind source separation
KW  - partial least squares
KW  - canonical correlations analysis
KW  - representational similarity analysis
KW  - deep learning
KW  - hierarchical Bayesian model
Y1  - 2018
U6  - https://doi.org/10.3389/fnhum.2018.00106
SN  - 1662-5161
VL  - 12
PB  - Frontiers Research Foundation
CY  - Lausanne
ER  - 
TY  - JOUR
A1  - Ventura-Bort, Carlos
A1  - Wirkner, Janine
A1  - Genheimer, Hannah
A1  - Wendt, Julia
A1  - Hamm, Alfons O.
A1  - Weymar, Mathias
T1  - Effects of Transcutaneous Vagus Nerve Stimulation (tVNS) on the P300 and Alpha-Amylase Level
BT  - A Pilot Study
JF  - Frontiers in Human Neuroscience
N2  - 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.
KW  - EEG
KW  - P300
KW  - tVNS
KW  - norepinephrine
KW  - locus coeruleus
KW  - salivary alpha-amylase
Y1  - 2018
U6  - https://doi.org/10.3389/fnhum.2018.00202
SN  - 1662-5161
VL  - 12
SP  - 1
EP  - 12
PB  - Frontiers Research Foundation
CY  - Lausanne
ER  - 
TY  - JOUR
A1  - Wieser, Matthias J.
A1  - Hambach, Anna
A1  - Weymar, Mathias
T1  - Neurophysiological correlates of attentional bias for emotional faces in socially anxious individuals
BT  - Evidence from a visual search task and N2pc
JF  - Biological psychology
N2  - Visual search paradigms have provided evidence for the enhanced capture of attention by threatening faces. Especially in social anxiety, hypervigilance for threatening faces has been found repeatedly across behavioral paradigms, whose reliability however have been questioned recently. In this EEG study, we sought to determine whether the detection of threat (angry faces) is specifically enhanced in individuals with high (HSA) compared to low social anxiety (LSA). In a visual search paradigm, the N2pc component of the event-related brain potential was measured as an electrophysiological indicator of attentional selection. Twenty-one HSA and twenty-one LSA participants were investigated while searching for threatening or friendly targets within an array of neutral faces, or neutral targets within threatening or friendly distractors. Whereas no differences were found in reaction times, HSA showed significant higher detection rates for angry faces, whereas LSA showed a clear ‘happiness bias’. HSA also showed enhanced N2pc amplitudes in response to emotional facial expressions (angry and happy), indicating a general attentional bias for emotional faces. Overall, the results show that social anxiety may be characterized not only by a spatial attentional bias for threatening faces, but for emotional faces in general. In addition, the results further demonstrate the utility of the N2pc component in capturing subtle attentional biases.
KW  - N2pc
KW  - EEG
KW  - Social anxiety
KW  - Facial expression
KW  - Threat
Y1  - 2018
U6  - https://doi.org/10.1016/j.biopsycho.2018.01.004
SN  - 0301-0511
SN  - 1873-6246
VL  - 132
SP  - 192
EP  - 201
PB  - Elsevier
CY  - Amsterdam
ER  -