TY - JOUR A1 - Sollfrank, Teresa A1 - Hart, Daniel A1 - Goodsell, Rachel A1 - Foster, Jonathan A1 - Tan, Tele T1 - 3D visualization of movements can amplify motor cortex activation during subsequent motor imagery JF - Frontiers in Human Neuroscience N2 - A repetitive movement practice by motor imagery (MI) can influence motor cortical excitability in the electroencephalogram (EEG). This study investigated if a realistic visualization in 3D of upper and lower limb movements can amplify motor related potentials during subsequent MI. We hypothesized that a richer sensory visualization might be more effective during instrumental conditioning, resulting in a more pronounced event related desynchronization (ERD) of the upper alpha band (10–12 Hz) over the sensorimotor cortices thereby potentially improving MI based brain-computer interface (BCI) protocols for motor rehabilitation. The results show a strong increase of the characteristic patterns of ERD of the upper alpha band components for left and right limb MI present over the sensorimotor areas in both visualization conditions. Overall, significant differences were observed as a function of visualization modality (VM; 2D vs. 3D). The largest upper alpha band power decrease was obtained during MI after a 3-dimensional visualization. In total in 12 out of 20 tasks the end-user of the 3D visualization group showed an enhanced upper alpha ERD relative to 2D VM group, with statistical significance in nine tasks.With a realistic visualization of the limb movements, we tried to increase motor cortex activation during subsequent MI. The feedback and the feedback environment should be inherently motivating and relevant for the learner and should have an appeal of novelty, real-world relevance or aesthetic value (Ryan and Deci, 2000; Merrill, 2007). Realistic visual feedback, consistent with the participant’s MI, might be helpful for accomplishing successful MI and the use of such feedback may assist in making BCI a more natural interface for MI based BCI rehabilitation. KW - 3-dimensional visualization KW - motor cortex activation KW - EEG KW - brain-computer interfaces Y1 - 2015 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-126058 VL - 9 IS - 463 ER - TY - JOUR A1 - Käthner, Ivo A1 - Halder, Sebastian A1 - Hintermüller, Christoph A1 - Espinosa, Arnau A1 - Guger, Christoph A1 - Miralles, Felip A1 - Vargiu, Eloisa A1 - Dauwalder, Stefan A1 - Rafael-Palou, Xavier A1 - Solà, Marc A1 - Daly, Jean M. A1 - Armstrong, Elaine A1 - Martin, Suzanne A1 - Kübler, Andrea T1 - A Multifunctional Brain-Computer Interface Intended for Home Use: An Evaluation with Healthy Participants and Potential End Users with Dry and Gel-Based Electrodes JF - Frontiers in Neuroscience N2 - Current brain-computer interface (BCIs) software is often tailored to the needs of scientists and technicians and therefore complex to allow for versatile use. To facilitate home use of BCIs a multifunctional P300 BCI with a graphical user interface intended for non-expert set-up and control was designed and implemented. The system includes applications for spelling, web access, entertainment, artistic expression and environmental control. In addition to new software, it also includes new hardware for the recording of electroencephalogram (EEG) signals. The EEG system consists of a small and wireless amplifier attached to a cap that can be equipped with gel-based or dry contact electrodes. The system was systematically evaluated with a healthy sample, and targeted end users of BCI technology, i.e., people with a varying degree of motor impairment tested the BCI in a series of individual case studies. Usability was assessed in terms of effectiveness, efficiency and satisfaction. Feedback of users was gathered with structured questionnaires. Two groups of healthy participants completed an experimental protocol with the gel-based and the dry contact electrodes (N = 10 each). The results demonstrated that all healthy participants gained control over the system and achieved satisfactory to high accuracies with both gel-based and dry electrodes (average error rates of 6 and 13%). Average satisfaction ratings were high, but certain aspects of the system such as the wearing comfort of the dry electrodes and design of the cap, and speed (in both groups) were criticized by some participants. Six potential end users tested the system during supervised sessions. The achieved accuracies varied greatly from no control to high control with accuracies comparable to that of healthy volunteers. Satisfaction ratings of the two end-users that gained control of the system were lower as compared to healthy participants. The advantages and disadvantages of the BCI and its applications are discussed and suggestions are presented for improvements to pave the way for user friendly BCIs intended to be used as assistive technology by persons with severe paralysis. KW - end-user evaluation KW - brain-computer interface KW - EEG KW - practical electrodes KW - assistive technology Y1 - 2017 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-157925 VL - 11 IS - 286 ER - TY - JOUR A1 - Simon, Nadine A1 - Käthner, Ivo A1 - Ruf, Carolin A. A1 - Pasqualotto, Emanuele A1 - Kübler, Andrea A1 - Halder, Sebastian T1 - An auditory multiclass brain-computer interface with natural stimuli: Usability evaluation with healthy participants and a motor impaired end user JF - Frontiers in Human Neuroscience N2 - Brain-computer interfaces (BCIs) can serve as muscle independent communication aids. Persons, who are unable to control their eye muscles (e.g., in the completely locked-in state) or have severe visual impairments for other reasons, need BCI systems that do not rely on the visual modality. For this reason, BCIs that employ auditory stimuli were suggested. In this study, a multiclass BCI spelling system was implemented that uses animal voices with directional cues to code rows and columns of a letter matrix. To reveal possible training effects with the system, 11 healthy participants performed spelling tasks on 2 consecutive days. In a second step, the system was tested by a participant with amyotrophic lateral sclerosis (ALS) in two sessions. In the first session, healthy participants spelled with an average accuracy of 76% (3.29 bits/min) that increased to 90% (4.23 bits/min) on the second day. Spelling accuracy by the participant with ALS was 20% in the first and 47% in the second session. The results indicate a strong training effect for both the healthy participants and the participant with ALS. While healthy participants reached high accuracies in the first session and second session, accuracies for the participant with ALS were not sufficient for satisfactory communication in both sessions. More training sessions might be needed to improve spelling accuracies. The study demonstrated the feasibility of the auditory BCI with healthy users and stresses the importance of training with auditory multiclass BCIs, especially for potential end-users of BCI with disease. KW - P300 KW - EEG KW - auditory BCI KW - brain-computer interface KW - communication KW - ALS Y1 - 2015 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-126450 VL - 8 IS - 1039 ER - TY - JOUR A1 - Cheetham, Marcus A1 - Wu, Lingdan A1 - Pauli, Paul A1 - Jancke, Lutz T1 - Arousal, valence, and the uncanny valley: psychophysiological and self-report findings JF - Frontiers in Psychology N2 - The main prediction of the Uncanny Valley Hypothesis (UVH) is that observation of humanlike characters that are difficult to distinguish from the human counterpart will evoke a state of negative affect. Well-established electrophysiological [late positive potential (LPP) and facial electromyography (EMG)] and self-report [Self-Assessment Manikin (SAM)] indices of valence and arousal, i.e., the primary orthogonal dimensions of affective experience, were used to test this prediction by examining affective experience in response to categorically ambiguous compared with unambiguous avatar and human faces (N = 30). LPP and EMG provided direct psychophysiological indices of affective state during passive observation and the SAM provided self-reported indices of affective state during explicit cognitive evaluation of static facial stimuli. The faces were drawn from well-controlled morph continua representing the UVH' dimension of human likeness (DHL). The results provide no support for the notion that category ambiguity along the DHL is specifically associated with enhanced experience of negative affect. On the contrary, the LPP and SAM-based measures of arousal and valence indicated a general increase in negative affective state (i.e., enhanced arousal and negative valence) with greater morph distance from the human end of the DHL. A second sample (N = 30) produced the same finding, using an ad hoc self-rating scale of feelings of familiarity, i.e., an oft-used measure of affective experience along the UVH' familiarity dimension. In conclusion, this multi-method approach using well-validated psychophysiological and self-rating indices of arousal and valence rejects for passive observation and for explicit affective evaluation of static faces the main prediction of the UVH. KW - emotional facial expressions KW - event-related potentials KW - electromyographic activity KW - startle reflex KW - arousal KW - unpleasant pictures KW - brain potentials KW - mere exposure KW - circumplex model KW - face recognition KW - neural response KW - valence KW - uncanny valley hypothesis KW - familiarity KW - EMG KW - EEG KW - LPP Y1 - 2015 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-151519 VL - 6 IS - 981 ER - TY - THES A1 - Käthner, Ivo R. J. T1 - Auditory and visual brain-computer interfaces as communication aids for persons with severe paralysis T1 - Akustische und visuelle Gehirn-Computer Schnittstellen als Kommunikationshilfen für Menschen mit schweren Muskellähmungen N2 - Brain-computer interfaces (BCIs) could provide a muscle-independent communication channel to persons with severe paralysis by translating brain activity into device commands. As a means of communication, in particular BCIs based on event-related potentials (ERPs) as control signal have been researched. Most of these BCIs rely on visual stimulation and have been investigated with healthy participants in controlled laboratory environments. In proof-of-principle studies targeted end users gained control over BCI systems; however, these systems are not yet established as an assistive technology for persons who would most benefit from them. The main aim of this thesis is to advance the usability of ERP-BCIs for target users. To this end, five studies with BCIs have been conducted that enabled users to communicate by focusing their attention on external stimuli. Two studies were conducted in order to demonstrate the advantages and to further improve the practical application of visual BCIs. In the first study, mental workload was experimentally manipulated during prolonged BCI operation. The study showed the robustness of the visual ERP-BCI since users maintained a satisfactory level of control despite constant distraction in the form of background noise. Moreover, neurophysiological markers that could potentially serve as indicators of high mental workload or fatigue were revealed. This is a first step towards future applications in which the BCI could adapt to the mental state of the user (e.g. pauses if high mental workload is detected to prevent false selections). In the second study, a head-mounted display (HMD), which assures that stimuli are presented in the field of view of the user, was evaluated. High accuracies and information transfer rates, similar to a conventional display, were achieved by healthy participants during a spelling task. Furthermore, a person in the locked-in state (LIS) gained control over the BCI using the HMD. The HMD might be particularly suited for initial communication attempts with persons in the LIS in situations, where mounting a conventional monitor is difficult or not feasible. Visual ERP-BCIs could prove valuable for persons with residual control over eye muscles and sufficient vision. However, since a substantial number of target users have limited control over eye movements and/or visual impairments, BCIs based on non-visual modalities are required. Therefore, a main aspect of this thesis was to improve an auditory paradigm that should enable motor impaired users to spell by focusing attention on different tones. The two conducted studies revealed that healthy participants were able to achieve high spelling performance with the BCI already in the first session and stress the importance of the choice of the stimulus material. The employed natural tones resulted in an increase in performance compared to a previous study that used artificial tones as stimuli. Furthermore, three out of five users with a varying degree of motor impairments could gain control over the system within the five conducted sessions. Their performance increased significantly from the first to the fifth session - an effect not previously observed for visual ERP-BCIs. Hence, training is particularly important when testing auditory multiclass BCIs with potential users. A prerequisite for user satisfaction is that the BCI technology matches user requirements. In this context, it is important to compare BCIs with already established assistive technology. Thus, the fifth study of this dissertation evaluated gaze dependent methods (EOG, eye tracking) as possible control signals for assistive technology and a binary auditory BCI with a person in the locked-in state. The study participant gained control over all tested systems and rated the ease of use of the BCI as the highest among the tested alternatives, but also rated it as the most tiring due to the high amount of attention that was needed for a simple selection. Further efforts are necessary to simplify operation of the BCI. The involvement of end users in all steps of the design and development process of BCIs will increase the likelihood that they can eventually be used as assistive technology in daily life. The work presented in this thesis is a substantial contribution towards the goal of re-enabling communication to users who cannot rely on motor activity to convey their thoughts. N2 - Gehirn-Computer Schnittstellen (engl. brain-computer interfaces, BCIs) könnten Menschen mit schweren Muskellähmungen muskelunabhängige Kommunikation ermöglichen, indem sie Gehirnaktivität in Steuerungsbefehle übersetzen. Zu Kommunikationszwecken wurden insbesondere BCIs erforscht, die auf ereigniskorrelierten Potenzialen (EKPs) als Steuerungssignal beruhen. Die Mehrzahl dieser BCIs basiert auf visuellen Paradigmen und wurde unter kontrollierten Laborbedingungen mit gesunden Versuchsteilnehmern untersucht. In Machbarkeitsstudien konnten auch Menschen mit schweren Muskellähmungen Kontrolle erlangen. Jedoch sind BCIs noch nicht im Alltag als Hilfsmittel für diejenigen etabliert, die am meisten von ihnen profitieren würden. Die Gebrauchstauglichkeit für diese Zielgruppe zu erhöhen, ist das Hauptziel der vorliegenden Arbeit. Zu diesem Zweck wurden fünf Studien mit BCIs durchgeführt, die Nutzern durch die Aufmerksamkeitsfokussierung auf externe Reize ermöglichen zu kommunizieren. Um die Vorteile der visuellen Paradigmen zu zeigen und die praktische Anwendbarkeit weiter zu verbessern, wurden zwei Studien durchgeführt. In der ersten Studie wurde die mentale Arbeitsbelastung während längerer Benutzung eines BCI experimentell manipuliert. Die Studie demonstrierte die Robustheit des EKP-BCI. Nutzer konnten trotz konstanter Ablenkung durch Hintergrundgeräusche ein zufriedenstellendes Kontrollniveau aufrechterhalten. Darüber hinaus wurden neurophysiologische Marker gefunden, die als Indikatoren hoher mentaler Arbeitsbelastung oder Ermüdung dienen können. Dies ist ein erster Schritt hin zu Anwendungen, bei denen sich das BCI dem mentalen Zustand des Benutzers anpasst (z.B. indem die Anwendung pausiert, wenn hohe Arbeitsbelastung detektiert wird, um Falschauswahlen zu verhindern). In der zweiten Studie wurde ein Head- Mounted Display (HMD) evaluiert, welches sicherstellt, dass alle Stimuli im Gesichtsfeld des Nutzers angezeigt werden. Dabei wurden von gesunden Versuchsteilnehmern hohe Genauigkeiten und Informationstransferraten beim Schreiben von Wörtern erzielt, vergleichbar mit denen eines herkömmlichen Bildschirms. Zusätzlich erlangte ein Nutzer im Locked-in-Zustand Kontrolle über das BCI mittels des HMD. Das HMD könnte sich insbesondere für initiale Kommunikationsversuche für Personen im Locked-in-Zustand eignen, wenn sich das Aufstellen eines konventionellen Bildschirms als schwierig oder unmöglich erweist. Visuelle EKP-BCIs könnten sich insgesamt als wertvoll für Personen herausstellen, die noch ihre Augenbewegungen kontrollieren können und über ausreichend Sehkraft verfügen. Da eine nicht unerhebliche Zahl von potenziellen Endbenutzern jedoch eingeschränkte Kontrolle über Augenbewegungen und/oder Sehbeeinträchtigungen hat, sind BCIs notwendig, die auf nicht-visuellen Modalitäten beruhen. Im Rahmen dieser Arbeit lag ein Fokus deshalb auf der Weiterentwicklung eines akustischen Paradigmas, welches Nutzern mit motorischen Einschränkungen das Buchstabieren durch die Aufmerksamkeitsfokussierung auf verschiedene Töne ermöglichen soll. Die beiden hierzu durchgeführten Studien zeigten, dass gesunde Versuchsteilnehmer bereits in der ersten Sitzung hohe Buchstabiergenauigkeiten erzielen konnten. Zudem unterstreichen diese Studien die Wichtigkeit der Wahl der Stimuli. Die in den beiden Studien verwendeten natürlichen Geräusche, führten zu einer Leistungsverbesserung verglichen mit einer vorausgegangenen Studie, die künstliche Töne verwendete. Darüber hinaus konnten drei von fünf Nutzern mit Muskellähmungen innerhalb von fünf Sitzungen Kontrolle über das System erlangen. Für die drei Nutzer war die Leistung in der fünften Sitzung dabei deutlich höher als in der ersten. Ein solcher Trainingseffekt wurde mit visuellen Paradigmen in vorausgegangenen Studien bisher nicht berichtet. Dieses Ergebnis betont daher die Bedeutsamkeit von Training während der Erprobung von akustischen Multi-Klassen-BCIs mit Endbenutzern. Eine Grundvoraussetzung für Nutzerzufriedenheit ist, dass die BCI Technologie den Bedürfnissen der Nutzer entspricht. In diesem Zusammenhang ist es wichtig, BCIs mit bereits etablierten Hilfsmitteln zu vergleichen. Daher wurden in der fünften Studie dieser Dissertation sowohl blickabhängige Methoden (EOG, Eye-Tracking) als auch ein akustisches BCI zur binären Kommunikation mit einem Nutzer im Locked-in-Zustand evaluiert. Der Studienteilnehmer erlangte über alle getesteten Systeme die Kontrolle und bewertete den Bedienkomfort des BCI am höchsten verglichen mit den anderen getesteten Methoden. Das BCI wurde jedoch aufgrund der hohen Konzentration, die für die Auswahl eines einzelnen Befehls benötigt wurde, als die ermüdendste bewertet. Weitere Entwicklungen sind notwendig, um die Bedienung des BCI noch stärker zu vereinfachen. Die Einbeziehung von Endbenutzern in alle Schritte des Entwicklungsprozesses eines BCI wird die Wahrscheinlichkeit erhöhen, dass es schließlich als Hilfsmittel im Alltag genutzt werden kann. Die vorliegende Dissertation leistet wesentliche Beiträge, um dieses Ziel zu erreichen: Nämlich Nutzern, welche sich nicht mittels motorischer Aktivität ausdrücken können, eine neue Form der Kommunikation zu ermöglichen. KW - Gehirn-Computer Schnittstelle KW - Elektronencephalographie KW - Kommunikationshilfe KW - Brain-computer interface KW - BCI KW - EEG KW - P300 KW - ALS KW - LIS KW - AAC Y1 - 2015 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-135477 ER - TY - THES A1 - Schreppel, Theresa T1 - Der Einfluss von Aufmerksamkeit und Interferenzkontrolle auf die Verarbeitung visueller Stimuli T1 - The influence of attention and interference control on the processing of visual stimuli N2 - Gegenstand der vorliegenden Arbeit war die Frage, inwieweit die neuronale Verarbeitung visueller Stimuli durch Prozesse der Aufmerksamkeit und des Arbeitsgedächtnisses moduliert werden kann. Darüber hinaus wurde untersucht, welche „top down“ Prozesse diese Modulation steuern. Dabei wurden zwei konkurrierende Ansichten als mögliche Erklärungsmodelle zugrunde gelegt und überprüft. Zum einen wäre es möglich, dass selektive Aufmerksamkeit zwei qualitativ unterschiedliche Mechanismen beinhaltet. Demnach würde neben dem Fokussieren auf relevante Informationen auch ein aktiver Prozess der Inhibition der Verarbeitung irrelevanter Stimuli existieren. Zum anderen ist es aber auch denkbar, dass aufgrund begrenzter Verarbeitungsressourcen das Fokussieren auf relevante Reize automatisch mit dem Nichtbeachten irrelevanter Stimuli einhergeht und nur ein Mechanismus existiert. In einem ersten Experiment wurde vorab die Alertness als ein grundlegender Prozess der Aufmerksamkeit mit der Nah-Infrarot Spektroskopie (NIRS) untersucht. Mittels eines zweigestuften Studiendesigns wurden in einem ersten Schritt für die Alertness relevante Regionen über fronto-temporalen Hirnarealen definiert. Als relevant erwiesen sich Areale des mittleren und superioren temporalen Kortex der rechten Hemisphäre und der ventrale Teil des inferioren frontalen Kortex der linken Hemisphäre. In einer zweiten Datenerhebung konnte für diese Regionen eine signifikant höhere Aktivierung während der Alertnessbedingung im Vergleich zu einer visuellen und motorischen Kontrollbedingung gefunden werden. Mit dem zweiten Experiment sollten bestehende, mit dem Elektroenzephalogramm (EEG) erhobene, Befunde zur Modulation der neuronalen Verarbeitung visueller Stimuli repliziert werden. Dies geschah mithilfe eines neu entwickelten Untersuchungsparadigmas, einer modifizierten n-back Aufgabe. Wie erwartet fand sich eine erhöhte Verarbeitung aufgaben-relevanter Reize im Vergleich zu einer perzeptuellen Kontrollbedingung. Die Verarbeitung irrelevanter Reize wurde allerdings nicht unterdrückt. Explorativ fand sich ein entsprechendes Korrelat der Aufmerksamkeitslenkung über frontalen Elektroden. In einem dritten Experiment wurde das modifizierte n-back Paradigma an die Anforderungen einer NIRS Messung angepasst, um frontale Effekte der Aufmerksamkeitslenkung direkter erfassen zu können als mit dem EEG. Wie erwartet fand sich bezüglich des Beachtens wie auch des Ignorierens von Stimuli eine Beteiligung frontaler Strukturen. Auf beachtete Stimuli folgte eine bilaterale Aktivierung des dorsolateralen präfrontalen Kortex (DL-PFK) und eine Aktivierung des linken inferioren frontalen Kortex bis hin zum prä- und postzentralen Kortex. Das Ignorieren visueller Stimuli führte zu einer weitläufigen Aktivierung des rechten präfrontalen Kortex (PFK). Eine Beteiligung des linken inferioren frontalen Gyrus an der Interferenzkontrolle konnte nicht wie erwartet nachgewiesen werden. Der Vergleich der beiden Aktivierungsmuster ergab keine signifikanten Unterschiede. Die zugrunde liegenden Prozesse des Arbeitsgedächtnisses und der Interferenzkontrolle führten also zu einer Aktivierung stark überlappender Hirnregionen. Nachdem die Ergebnisse der Experimente 2 und 3 keinerlei Hinweise auf einen aktiven Prozess der Interferenzinhibition nachweisen konnten, wurde im Experiment 4 die bisher genutzte 1-back Aufgabe durch eine schwierigere 2-back Aufgabe ersetzt. Aufgrund der erhöhten Auslastung des Arbeitsgedächtnisses sollte eine stärkere Anstrengung und damit eine verstärkte frontale Aktivierung bei der Interferenzinhibition auftreten. Diese Hypothese wurde mit einer frontalen NIRS Messung überprüft (Experiment 4a). Wie erwartet führte die erhöhte Auslastung des Arbeitsgedächtnisses zu einer verstärkten Aktivierung des PFK bezüglich beachteter Reize. Hinsichtlich ignorierter Reize fand sich allerdings keine frontale Beteiligung. Parallel erhobene EEG Daten zeigten keinen Unterschied zwischen der Verarbeitung beachteter und ignorierter Gesichter. Die Verarbeitung passiv betrachteter Gesichter war im Gegensatz zu beachteten und ignorierten Gesichtern vermindert. Im zweiten Teil der Studie (Experiment 4b) wurden erstmals die okzipitalen Effekte der Aufmerksamkeitslenkung mit der NIRS erfasst. Im Einklang mit den Ergebnissen der ersten EEG Studie (Experiment 2) fand sich zwar eine verstärkte Verarbeitung beachteter, aber keine verminderte Verarbeitung ignorierter Reize. Zusammengenommen sprechen die fehlende aktive Inhibition von Distraktorreizen im okzipitalen Kortex und die vergleichbaren neuronalen Korrelate von Prozessen des Arbeitsgedächtnisses und der Interferenzinhibition im frontalen Kortex für die Hypothese einer Aufteilung von begrenzten Verarbeitungsressourcen zugunsten beachteter Reize. N2 - The aim of the present work was to investigate, to what extend the neural processing of visual stimuli could be modulated by processes of attention and working memory and which top down processes control this modulation. Two competing explanatory models were proved in the present work. On the one hand it is possible that selective attention comprise two qualitatively different mechanisms, the focussing on relevant information and the active inhibition of irrelevant stimuli. On the other hand it is possible that the limited processing capacities lead to an automatic disregard of irrelevant stimuli when focussing on relevant information. According to this, there would be only one mechanism. In a first experiment alertness was investigated with near-infrared spectroscopy (NIRS) as a basic process of attention. In a two step design relevant areas for alertness over the fronto-temporal cortex were defined first. Alertness related activity was found in the middle and superior temporal cortex of the right hemisphere and in the ventral part of the inferior frontal cortex of the left hemisphere. The analyses of a second measurement for these specific regions revealed a significantly increased activation for alertness in contrast to a visual and a motor control condition. The aim of a second experiment was to replicate existing electroencephalographic (EEG) results of the modulation of the neural processing of visual stimuli with a new developed paradigm, a modified version of the n-back task. As expected there was a higher processing of relevant stimuli in comparison to a perceptual control condition. The processing of irrelevant stimuli was not suppressed. Explorative, there was an analogue result of the modulation of attention over frontal electrodes. In a third experiment the modified n-back paradigm was adjusted to the standards of NIRS measurements to capture frontal effects of attentional modulation more immediate than with EEG. As expected both attended and ignored stimuli were associated with activation of frontal structures. Relevant stimuli were linked with a bilateral activation of the dorsolateral prefrontal cortex (DL-PFC) and activation from the left inferior frontal cortex to the pre- and postcentral cortex. Irrelevant stimuli were linked with a distributed activation of the right PFC. An involvement of the left frontal gyrus could not be verified. The comparison of the two activation patterns revealed no significant difference, the basic processes of working memory and interference control led to an activation of highly overlapping brain regions. The results of the experiments 2 and 3 revealed no evidence of an active process of interference control. Therefore, the 1-back task was replaced by a more difficult 2-back task in experiment 4. Due to the higher working memory load, there should be a stronger effort and therefore a stronger frontal activation during interference inhibition. This hypothesis was proved with a frontal NIRS measurement (experiment 4a). As expected, the higher working memory load led to a stronger activation of the PFC in respect of the relevant stimuli. Concerning irrelevant stimuli, there was no frontal activation. EEG data that were collected simultaneously showed no difference between the processing of attended and ignored faces. In comparison to that the processing of passively viewed faces was decreased. The second part of this study examined occipital effects of attentional modulation with NIRS for the first time. In line with the results of the first EEG study (experiment 2) there was an enhanced processing of relevant, but no decreased processing of ignored stimuli. In sum, the absent active inhibition of distractors in the occipital cortex and the similar neural correlates of processes of working memory and interference inhibition in the frontal cortex argue for the hypothesis of one uniform mechanism of focussing attention without an active and independent mechanism of interference inhibition. KW - Arbeitsgedächtnis KW - Visuelle Aufmerksamkeit KW - Elektroencephalographie KW - Bildgebendes Verfahren KW - Hirnforschung KW - working memory KW - visual attention KW - EEG KW - brain mapping Y1 - 2008 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-32496 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: 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 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-196129 SN - 1662-5161 VL - 12 IS - 202 ER - TY - THES A1 - Stegmann, Yannik T1 - Electrocortical mechanisms of sustained attention during the acquisition and interaction of conditioned fear and anxiety T1 - Elektrokortikale Mechanismen der Aufmerksamkeit während der Akquisition und Interaktion konditionierter Furcht und Angst N2 - Adapting defensive behavior to the characteristics of a threatening situation is a fundamental function of the brain. Particularly, threat imminence plays a major role for the organization of defensive responses. Acute threat prompts phasic physiological responses, which are usually associated with an intense feeling of fear. In contrast, diffuse and potentially threatening situations elicit a sustained state of anxious apprehension. Detection of the threatening stimulus defines the key event in this framework, initiating the transition from potential to acute threat. Consequently, attention to threat is crucial for supporting defensive behavior. The functions of attention are finely tuned to the characteristics of a threatening situation. Potential threat is associated with hypervigilance, in order to facilitate threat detection. Once a threatening stimulus has been identified, attention is selectively focused on the source of danger. Even though the concepts of selective attention and hypervigilance to threat are well established, evidence for their neural correlates remain scarce. Therefore, a major goal of this thesis is to elucidate the neural correlates of selective attention to acute threat and hypervigilance during potential threat. A second aim of this thesis is to provide a mechanistic account for the interaction of fear and anxiety. While contemporary models view fear and anxiety as mutually exclusive, recent findings for the neural networks of fear and anxiety suggest potential interactions. In four studies, aversive cue conditioning was used to induce acute threat, while context conditioning served as a laboratory model of potential threat. To quantify neural correlates of selective attention and hypervigilance, steady-state visual evoked potentials (ssVEPs) were measured as an index of visuocortical responding. Study 1 compared visuocortical responses to acute and potential threat for high versus low trait-anxious individuals. All individuals demonstrated enhanced electrocortical responses to the central cue in the acute threat condition, suggesting evidence for the neural correlate of selective attention. However, only low anxious individuals revealed facilitated processing of the contexts in the potential threat condition, reflecting a neural correlate of hypervigilance. High anxious individuals did not discriminate among contexts. These findings contribute to the notion of aberrational processing of potential threat for high anxious individuals. Study 2 and 3 realized orthogonal combinations of cue and context conditioning to investigate potential interactions of fear and anxiety. In contrast to Study 1 and 2, Study 3 used verbal instructions to induce potentially threatening contexts. Besides ssVEPs, threat ratings and skin conductance responses (SCRs) were recorded as efferent indices of defensive responding. None of these studies found further evidence for the neural correlates of hypervigilance and selective attention. However, results for ratings and SCRs revealed additive effects of fear and anxiety, suggesting that fear and anxiety are not mutually exclusive, but interact linearly to organize and facilitate defensive behavior. Study 4 tested ssVEPs to more ecologically valid forms of context conditioning, using flickering video stimuli of virtual offices to establish context representations. Contrary to expectations, results revealed decreased visuocortical responses during sustained presentations of anxiety compared to neutral contexts. A disruption of ssVEP signals eventually suggests interferences by continuously changing video streams which are enhanced as a function of motivational relevance. In summary, this thesis provided evidence for the neural correlates of attention only for isolated forms of fear and anxiety, but not for their interaction. In contrast, an additive interaction model of fear and anxiety for measures of defensive responding offers a new perspective on the topography of defensive behavior. N2 - ZusammenfassungDie Anpassung defensiver Verhaltensweisen an die Anforderungen bedrohlicher Sit-uationen ist eine fundamentale Funktion des Gehirns. Akute Bedrohung führt in der Regel zu kurz-anhaltenden, physiologischen Reaktionen, die mit einem Gefühlintensiver Furcht einhergehen, während Situationen potenzieller Bedrohung zu einem anhaltenden Zustand erhöhter Angst führen. Dabei spielt das Erkennen der Gefahr eine besondere Rolle, da sie den Übergang von potenzieller zu akuter Bedrohung initiiert. Demnach kommt der Aufmerksamkeit eine wichtige Funktion bei der Unterstützung defensiver Verhaltensweisen zu. Mechanismen der Aufmerksamkeit sind dabei präzise auf die jeweilige Situation abgestimmt. Potenzielle Bedrohung führt zu Hypervigilanz, um bedrohliche Reize schneller zu entdecken ... KW - Furcht KW - Angst KW - Aufmerksamkeit KW - ssVEP KW - EEG KW - Conditioning KW - Visuelle Aufmerksamkeit Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-237700 ER - TY - JOUR A1 - Martens, Suzanne A1 - Bensch, Michael A1 - Halder, Sebastian A1 - Hill, Jeremy A1 - Nijboer, Femke A1 - Ramos-Murguialday, Ander A1 - Schoelkopf, Bernhard A1 - Birbaumer, Niels A1 - Gharabaghi, Alireza T1 - Epidural electrocorticography for monitoring of arousal in locked-in state JF - Frontiers in Human Neuroscience N2 - Electroencephalography (EEG) often fails to assess both the level (i.e., arousal) and the content (i.e., awareness) of pathologically altered consciousness in patients without motor responsiveness. This might be related to a decline of awareness, to episodes of low arousal and disturbed sleep patterns, and/or to distorting and attenuating effects of the skull and intermediate tissue on the recorded brain signals. Novel approaches are required to overcome these limitations. We introduced epidural electrocorticography (ECoG) for monitoring of cortical physiology in a late-stage amytrophic lateral sclerosis patient in completely locked-in state (CLIS) Despite long-term application for a period of six months, no implant related complications occurred. Recordings from the left frontal cortex were sufficient to identify three arousal states. Spectral analysis of the intrinsic oscillatory activity enabled us to extract state-dependent dominant frequencies at <4, similar to 7 and similar to 20 Hz, representing sleep-like periods, and phases of low and elevated arousal, respectively. In the absence of other biomarkers, ECoG proved to be a reliable tool for monitoring circadian rhythmicity, i.e., avoiding interference with the patient when he was sleeping and exploiting time windows of responsiveness. Moreover, the effects of interventions addressing the patient's arousal, e.g., amantadine medication, could be evaluated objectively on the basis of physiological markers, even in the absence of behavioral parameters. Epidural ECoG constitutes a feasible trade-off between surgical risk and quality of recorded brain signals to gain information on the patient's present level of arousal. This approach enables us to optimize the timing of interactions and medical interventions, all of which should take place when the patient is in a phase of high arousal. Furthermore, avoiding low responsiveness periods will facilitate measures to implement alternative communication pathways involving brain-computer interfaces (BCI). KW - temporal-lobe epilepsy KW - neuroprosthetic devices KW - brain computer interface KW - event-related potentials KW - intraoperative electrocoicography KW - electrocorticography KW - epidural recording KW - locked-in state KW - coma KW - consciousness KW - paralyzed patients KW - EEG KW - sleep KW - communication KW - frequencies KW - amyotrophic-lateral-sclerosis Y1 - 2014 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-114863 VL - 8 ER - TY - JOUR A1 - Rodrigues, Johannes A1 - Weiß, Martin A1 - Hewig, Johannes A1 - Allen, John J. B. T1 - EPOS: EEG Processing Open-Source Scripts JF - Frontiers in Neuroscience N2 - Background: Since the replication crisis, standardization has become even more important in psychological science and neuroscience. As a result, many methods are being reconsidered, and researchers’ degrees of freedom in these methods are being discussed as a potential source of inconsistencies across studies. New Method: With the aim of addressing these subjectivity issues, we have been working on a tutorial-like EEG (pre-)processing pipeline to achieve an automated method based on the semi-automated analysis proposed by Delorme and Makeig. Results: Two scripts are presented and explained step-by-step to perform basic, informed ERP and frequency-domain analyses, including data export to statistical programs and visual representations of the data. The open-source software EEGlab in MATLAB is used as the data handling platform, but scripts based on code provided by Mike Cohen (2014) are also included. Comparison with existing methods: This accompanying tutorial-like article explains and shows how the processing of our automated pipeline affects the data and addresses, especially beginners in EEG-analysis, as other (pre)-processing chains are mostly targeting rather informed users in specialized areas or only parts of a complete procedure. In this context, we compared our pipeline with a selection of existing approaches. Conclusion: The need for standardization and replication is evident, yet it is equally important to control the plausibility of the suggested solution by data exploration. Here, we provide the community with a tool to enhance the understanding and capability of EEG-analysis. We aim to contribute to comprehensive and reliable analyses for neuro-scientific research. KW - EEG KW - electroencephalography KW - event-related potentials-ERP KW - EEG processing KW - EEG preprocessing KW - EEG frequency band analysis Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-240221 SN - 1662-453X VL - 15 ER - TY - THES A1 - Sollfrank, Teresa T1 - Feedback efficiency and training effects during alpha band modulation over the sensorimotor cortex T1 - Die Wirksamkeit von Feedback und Trainingseffekten während der Alphaband Modulation über dem menschlichen sensomotorischen Cortex N2 - Neural oscillations can be measured by electroencephalography (EEG) and these oscillations can be characterized by their frequency, amplitude and phase. The mechanistic properties of neural oscillations and their synchronization are able to explain various aspects of many cognitive functions such as motor control, memory, attention, information transfer across brain regions, segmentation of the sensory input and perception (Arnal and Giraud, 2012). The alpha band frequency is the dominant oscillation in the human brain. This oscillatory activity is found in the scalp EEG at frequencies around 8-13 Hz in all healthy adults (Makeig et al., 2002) and considerable interest has been generated in exploring EEG alpha oscillations with regard to their role in cognitive (Klimesch et al., 1993; Hanselmayr et al., 2005), sensorimotor (Birbaumer, 2006; Sauseng et al., 2009) and physiological (Lehmann, 1971; Niedermeyer, 1997; Kiyatkin, 2010) aspects of human life. The ability to voluntarily regulate the alpha amplitude can be learned with neurofeedback training and offers the possibility to control a brain-computer interface (BCI), a muscle independent interaction channel. BCI research is predominantly focused on the signal processing, the classification and the algorithms necessary to translate brain signals into control commands than on the person interacting with the technical system. The end-user must be properly trained to be able to successfully use the BCI and factors such as task instructions, training, and especially feedback can therefore play an important role in learning to control a BCI (Neumann and Kübler, 2003; Pfurtscheller et al., 2006, 2007; Allison and Neuper, 2010; Friedrich et al., 2012; Kaufmann et al., 2013; Lotte et al., 2013). The main purpose of this thesis was to investigate how end-users can efficiently be trained to perform alpha band modulation recorded over their sensorimotor cortex. The herein presented work comprises three studies with healthy participants and participants with schizophrenia focusing on the effects of feedback and training time on cortical activation patterns and performance. In the first study, the application of a realistic visual feedback to support end-users in developing a concrete feeling of kinesthetic motor imagery was tested in 2D and 3D visualization modality during a single training session. Participants were able to elicit the typical event-related desynchronisation responses over sensorimotor cortex in both conditions but the most significant decrease in the alpha band power was obtained following the three-dimensional realistic visualization. The second study strengthen the hypothesis that an enriched visual feedback with information about the quality of the input signal supports an easier approach for motor imagery based BCI control and can help to enhance performance. Significantly better performance levels were measurable during five online training sessions in the groups with enriched feedback as compared to a conventional simple visual feedback group, without significant differences in performance between the unimodal (visual) and multimodal (auditory–visual) feedback modality. Furthermore, the last study, in which people with schizophrenia participated in multiple sessions with simple feedback, demonstrated that these patients can learn to voluntarily regulate their alpha band. Compared to the healthy group they required longer training times and could not achieve performance levels as high as the control group. Nonetheless, alpha neurofeedback training lead to a constant increase of the alpha resting power across all 20 training session. To date only little is known about the effects of feedback and training time on BCI performance and cortical activation patterns. The presented work contributes to the evidence that healthy individuals can benefit from enriched feedback: A realistic presentation can support participants in getting a concrete feeling of motor imagery and enriched feedback, which instructs participants about the quality of their input signal can give support while learning to control the BCI. This thesis demonstrates that people with schizophrenia can learn to gain control of their alpha oscillations recorded over the sensorimotor cortex when participating in sufficient training sessions. In conclusion, this thesis improved current motor imagery BCI feedback protocols and enhanced our understanding of the interplay between feedback and BCI performance. N2 - Die Wirksamkeit von Feedback und Trainingseffekten während der Alphaband Modulation über dem menschlichen sensomotorischen Cortex KW - Neurofeedback KW - Gehirn-Computer-Schnittstelle KW - Brain-computer interface KW - Übung KW - Alpha Neurofeedback KW - EEG Y1 - 2015 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-131769 ER - TY - JOUR A1 - Stegmann, Yannik A1 - Andreatta, Marta A1 - Pauli, Paul A1 - Keil, Andreas A1 - Wieser, Matthias J. T1 - Investigating sustained attention in contextual threat using steady‐state VEPs evoked by flickering video stimuli JF - Psychophysiology N2 - Anxiety is characterized by anxious anticipation and heightened vigilance to uncertain threat. However, if threat is not reliably indicated by a specific cue, the context in which threat was previously experienced becomes its best predictor, leading to anxiety. A suitable means to induce anxiety experimentally is context conditioning: In one context (CTX+), an unpredictable aversive stimulus (US) is repeatedly presented, in contrast to a second context (CTX−), in which no US is ever presented. In this EEG study, we investigated attentional mechanisms during acquisition and extinction learning in 38 participants, who underwent a context conditioning protocol. Flickering video stimuli (32 s clips depicting virtual offices representing CTX+/−) were used to evoke steady‐state visual evoked potentials (ssVEPs) as an index of visuocortical engagement with the contexts. Analyses of the electrocortical responses suggest a successful induction of the ssVEP signal by video presentation in flicker mode. Furthermore, we found clear indices of context conditioning and extinction learning on a subjective level, while cortical processing of the CTX+ was unexpectedly reduced during video presentation. The differences between CTX+ and CTX− diminished during extinction learning. Together, these results indicate that the dynamic sensory input of the video presentation leads to disruptions in the ssVEP signal, which is greater for motivationally significant, threatening contexts. KW - anxiety KW - EEG KW - oscillation KW - threat KW - time frequency analyses KW - visual processes Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-312430 VL - 60 IS - 5 ER - TY - THES A1 - Karl, Christian T1 - Kontextuelle und differentielle Einflüsse auf die neurophysiologische Verarbeitung wütender und neutraler Gesichter T1 - Contextual and differential effects on the neurophysiological processing of angry and neutral faces N2 - In dieser EEG Untersuchung wurde der Einfluss von zuvor präsentierten Abfolgen wütender und neutraler Gesichtsausdrücke auf die neurokognitive Verarbeitung eines aktuell wahrgenommenen Gesichts unter Berücksichtigung des modulierenden Effekts der individuellen Ängstlichkeit, sowie eines sozial stressenden Kontextes und einer erhöhten kognitiven Auslastung erforscht. Die Ergebnisse lieferten bereits auf der Ebene der basalen visuellen Gesichtsanalyse Belege für eine parallele Verarbeitung und Integration von strukturellen und emotionalen Gesichtsinformationen. Zudem konnte schon in dieser frühen Phase ein genereller kontextueller Einfluss von Gesichtssequenzen auf die kognitive Gesichtsverarbeitung nachgewiesen werden, welcher sogar in späteren Phasen der kognitiven Verarbeitung noch zunahm. Damit konnte nachgewiesen werden, dass die zeitliche Integration, d.h. die spezifische Abfolge wahrgenommener Gesichter eine wichtige Rolle für die kognitive Evaluation des aktuell perzipierten Gesichtes spielt. Diese Ergebnisse wurden zudem in einer Revision des Gesichtsverarbeitungsmodells von Haxby und Kollegen verordnet und in einer sLORETA Analyse dargestellt. Die Befunde zur individuellen Ängstlichkeit und kognitiven Auslastung bestätigten außerdem die Attentional Control Theorie und das Dual Mechanisms of Control Modell. N2 - In this EEG study I investigated the influence of previously presented sequences of angry and neutral facial expressions on the neurocognitive processing of a currently perceived face, taking into account the modulating influence of individual anxiety, as well as the influence of a socially stressful context and an increased cognitive load. The results provided evidence for parallel processing and integration of structural and emotional facial information already at the level of basal visual face analysis. Moreover, as early as this stage, there was evidence for a general contextual influence of face sequences on the cognitive processing of the current face, with it‘s effect increasing further at later stages of cognitive processing, thereby proving that the temporal integration, i. e. that the specific sequence of previously perceived faces plays an important role in the cognitive evaluation of the currently perceived face. These results were also classified in a revised version of Haxby and colleagues' neural model of face processing and presented in a sLORETA analysis. Furthermore, the findings concerning the individual anxiety and cognitive load confirmed the Attentional Control Theory and the Dual Mechanisms of Control Model. KW - Visuelle Wahrnehmung KW - Gesicht KW - EEG KW - Sequenzen KW - Attentional control KW - Elektroencephalogramm KW - Angst KW - Wut KW - Reihenfolge Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-183067 ER - TY - THES A1 - Rodrigues, Johannes T1 - Let me change your mind… Frontal brain activity in a virtual T-maze T1 - Let me change your mind… Frontale Hirnaktivierung in einem virtuellen T-Labyrinth N2 - Frontal asymmetry, a construct invented by Richard Davidson, linking positive and negative valence as well as approach and withdrawal motivation to lateralized frontal brain activation has been investigated for over thirty years. The frontal activation patterns described as relevant were measured via alpha-band frequency activity (8-13 Hz) as a measurement of deactivation in electroencephalography (EEG) for homologous electrode pairs, especially for the electrode position F4/ F3 to account for the frontal relative lateralized brain activation. Three different theories about frontal activation patterns linked to motivational states were investigated in two studies. The valence theory of Davidson (1984; 1998a; 1998b) and its extension to the motivational direction theory by Harmon-Jones and Allen (1998) refers to the approach motivation with relative left frontal brain activity (indicated by relative right frontal alpha activity) and to withdrawal motivation with relative right frontal brain activation (indicated by relative left frontal alpha activity). The second theory proposed by Hewig and colleagues (2004; 2005; 2006) integrates the findings of Davidson and Harmon – Jones and Allen with the reinforcement sensitivity theory of Jeffrey A. Gray (1982, 1991). Hewig sees the lateralized frontal approach system and withdrawal system proposed by Davidson as subsystems of the behavioral activation system proposed by Gray and bilateral frontal activation as a biological marker for the behavioral activation system. The third theory investigated in the present studies is the theory from Wacker and colleagues (2003; 2008; 2010) where the frontal asymmetrical brain activation patterns are linked to the revised reinforcement sensitivity theory of Gray and McNaughton (2000). Here, right frontal brain activity (indicated by lower relative right frontal alpha activity) accounts for conflict, behavioral inhibition and activity of the revised behavioral inhibition system, while left frontal brain activation (indicated by lower relative left frontal alpha activity) stands for active behavior and the activity of the revised behavioral activation system as well as the activation of the revised flight fight freezing system. In order to investigate these three theories, a virtual reality T-maze paradigm was introduced to evoke motivational states in the participants, offering the opportunity to measure frontal brain activation patterns via EEG and behavior simultaneously in the first study. In the second study the virtual reality paradigm was additionally compared to mental imagery and a movie paradigm, two well-known state inducing paradigms in the research field of frontal asymmetry. In the two studies, there was confirming evidence for the theory of Hewig and colleages (2004; 2005; 2006), showing higher bilateral frontal activation for active behavior and lateralized frontal activation patterns for approach (left frontal brain activation) and avoidance (right frontal brain activation) behavior. Additionally a limitation for the capability model of anterior brain asymmetry proposed by Coan and colleagues (2006), where the frontal asymmetry should be dependent on the relevant traits driving the frontal asymmetry pattern if a relevant situation occurs, could be found. As the very intense virtual reality paradigm did not lead to a difference of frontal brain activation patterns compared to the mental imagery paradigm or the movie paradigm for the traits of the participants, the trait dependency of the frontal asymmetry in a relevant situation might not be given, if the intensity of the situation exceeds a certain level. Nevertheless there was an influence of the traits in the virtual reality T-maze paradigm, because the shown behavior in the maze was trait-dependent. The implications of the findings are multifarious, leading from possible objective personality testing via diversification of the virtual reality paradigm to even clinical implications for depression treatments based on changes in the lateralized frontal brain activation patterns for changes in the motivational aspects, but also for changes in bilateral frontal brain activation when it comes to the drive and preparedness for action in patients. Finally, with the limitation of the capability model, additional variance in the different findings about frontal asymmetry can be explained by taking the intensity of a state manipulation into account. N2 - Frontal Asymmetrie, ein Konstrukt, erfunden von Richard Davidson, das positive und negative Valenz sowie Annäherungsmotivation und Vermeidungsmotivation mit lateralisierter Frontalhirnaktivierung verbindet, wird seit mehr als dreißig Jahren untersucht. Die frontalen Aktivierungsmuster, die als relevant beschrieben wurden, wurden über Alpha-Frequenzband Aktivität (8-13 Hz) im Elektroenzephalogramm (EEG) als Maß für die Deaktivierung für die homologe Elektrodenpaare, insbesondere an der Elektrodenposition F4 / F3 gemessen, um die relative frontale lateralisierte Hirnaktivierung zu messen. In der vorliegenden Arbeit wurden drei verschiedene Theorien über frontale Aktivierungsmuster, die mit motivationalen Zuständen verbunden sind, in zwei Studien untersucht. Die „valence theory“ von Davidson (1984; 1998a; 1998b) und ihre Erweiterung zur „motivational direction theory“ von Harmon Jones und Allen (1998) verbindet Annäherungsmotivation mit relativer linksseitiger frontalen Hirnaktivität (durch relative rechtsfrontale Alpha-Aktivität angezeigt) und Rückzugsmotivation mit relativer rechtsfrontaler Hirnaktivierung (durch relative linksfrontale Alpha-Aktivität angezeigt). Die zweite Theorie von Hewig und Kollegen (2004; 2005; 2006) integriert die Ergebnisse von Davidson und Harmon - Jones und Allen mit der „reinforcement sensitvity theory“ von Jeffrey A. Gray (1982, 1991). Hewig sieht das lateralisierte frontale „approach system“ (Annäherungsverhalten, links frontal), und das „withdrawal system“ (Rückzugsverhalten, rechts frontal) von Davidson als Subsysteme des „behavioral activation system“ von Gray und bilaterale frontale Aktivierung als biologische Marker für das „behavioral activation system“ und aktives Verhalten. Die dritte Theorie, die in den vorliegenden Studien untersucht wird, ist die Theorie von Wacker und Kollegen (2003; 2008; 2010), bei der die frontalen asymmetrischen Gehirnaktivierungsmuster der „revidierten reinforcement sensitvity theory“ von Gray und McNaughton (2000) zugeordnet werden. Hier steht die rechte frontale Hirnaktivität (ermittelt durch geringere relative rechten frontalen Alpha-Aktivität) für Konflikte, Verhaltenshemmung und die Aktivität des „revised behavioral inhibition system“, während links frontale Hirnaktivierung (ermittelt durch niedrigere relative links frontal Alpha-Aktivität) für aktives Verhalten und die Aktivität des „revised behavioral activation system“ sowie die Aktivierung des „revised fight flight freezing system“ steht. Um diese drei Theorien zu untersuchen, wurde eine virtuelles T-Labyrinth Paradigma in der ersten Studie eingeführt, um motivationale Zustände bei den Teilnehmern zu induzieren und die Möglichkeit zu erhalten, frontale Hirnaktivierungsmuster im EEG und Verhalten gleichzeitig zu messen. In der zweiten Studie wurde das virtuelle Realität Paradigma zusätzlich im Vergleich zu einem mentalen Vorstellungsparadigma und einem Film-Paradigma, zwei bekannten Paradigmen für die Induktion von motivationalen Zuständen im Bereich der Forschung der frontalen Asymmetrie, eingesetzt. In den beiden Studien konnte die Theorie von Hewig und colleages (2004; 2005; 2006) belegt werden, da höhere bilaterale frontale Aktivierung für aktives Verhalten und lateralisierte frontale Aktivierungsmuster für Annäherung (linksfrontale Hirnaktivierung) und Vermeidung (rechtsfrontale Hirnaktivierung) gefunden wurde. Zusätzlich wurde eine Limitation des „capability models of anterior frontal asymmetry“ von Coan und Kollegen (2006), nach der die frontale Asymmetrie von relevanten Persönlichkeitsmerkmalen in den entsprechend der Eigenschaft relevanten Situationen beeinflusst werden sollte, gefunden. Da das sehr intensive virtuelle Realität Paradigma im Gegensatz zu den mentalen Vorstellungen und dem Film Paradigma keine Abhängigkeit der frontalen Gehirnaktivierungsmustern in den entsprechenden Situationen von den Persönlichkeitseigenschaften zeigte, kann diese Abhängigkeit der frontalen Asymmetrie von der Persönlichkeit nicht gefunden werden, wenn die Intensität der Situation einen bestimmten Wert überschreitet. Dennoch gab es einen Einfluss der Persönlichkeitseigenschaften in dem virtuellen T-Labyrinth, denn das beobachtbare Verhalten im Labyrinth war persönlichkeitsabhängig. Die praktische Bedeutung dieser Erkenntnisse sind vielfältig und reichen von möglichen objektiven Persönlichkeitstests durch eine Erweiterung des virtuellen Realität Paradigmas bis hin zu klinischen Implikationen für die Behandlung depressiver Patienten, basierend auf der Veränderungen der lateralisierten Frontalhirnaktivierungsmustern um motivationale Aspekte zu verändern, oder aber der für Änderungen bilateraler frontale Gehirnaktivierung, um den Antrieb und die Handlungsbereitschaft bei Patienten zu verändern. Schließlich kann mittels der Limitierung des „capability models“ zusätzliche Variation in den verschiedenen Befunden zur frontalen Asymmetrie erklärt werden, indem man die Intensität der Zustandsmanipulation berücksichtigt. KW - Electroencephalographie KW - Motivation KW - Frontal asymmetry KW - virtual reality T-maze KW - reinforcement sensitivity theory KW - bilateral BAS model KW - EEG KW - virtuelle Realität KW - Alpha-Aktivität Y1 - 2016 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-143280 ER - TY - JOUR A1 - Thiele, Jonas A. A1 - Richter, Aylin A1 - Hilger, Kirsten T1 - Multimodal brain signal complexity predicts human intelligence JF - eNeuro N2 - Spontaneous brain activity builds the foundation for human cognitive processing during external demands. Neuroimaging studies based on functional magnetic resonance imaging (fMRI) identified specific characteristics of spontaneous (intrinsic) brain dynamics to be associated with individual differences in general cognitive ability, i.e., intelligence. However, fMRI research is inherently limited by low temporal resolution, thus, preventing conclusions about neural fluctuations within the range of milliseconds. Here, we used resting-state electroencephalographical (EEG) recordings from 144 healthy adults to test whether individual differences in intelligence (Raven’s Advanced Progressive Matrices scores) can be predicted from the complexity of temporally highly resolved intrinsic brain signals. We compared different operationalizations of brain signal complexity (multiscale entropy, Shannon entropy, Fuzzy entropy, and specific characteristics of microstates) regarding their relation to intelligence. The results indicate that associations between brain signal complexity measures and intelligence are of small effect sizes (r ∼ 0.20) and vary across different spatial and temporal scales. Specifically, higher intelligence scores were associated with lower complexity in local aspects of neural processing, and less activity in task-negative brain regions belonging to the default-mode network. Finally, we combined multiple measures of brain signal complexity to show that individual intelligence scores can be significantly predicted with a multimodal model within the sample (10-fold cross-validation) as well as in an independent sample (external replication, N = 57). In sum, our results highlight the temporal and spatial dependency of associations between intelligence and intrinsic brain dynamics, proposing multimodal approaches as promising means for future neuroscientific research on complex human traits. KW - brain signal complexity KW - cognitive ability KW - EEG KW - intelligence KW - microstates KW - resting-state Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-312949 VL - 10 IS - 2 ER - TY - THES A1 - Herrmann, Martin Josef T1 - Neurophysiologische Korrelate der Verarbeitung von Gesichtern und emotionalen Gesichtsausdrücken bei Gesunden und Patienten mit schizophrenen Erkrankungen T1 - Neurophysiologic correlates of face processing and facial affect decoding in healthy controls and schizophrenic patients N2 - Ausgangspunkt für diese Arbeit war die Diskrepanz zwischen der vielfach belegten Schwierigkeit schizophrener Patienten bei der Dekodierung emotionaler Gesichtsausdrücke und dem mangelhaften Wissen über die hierfür verantwortlichen Prozesse. In der Literatur der letzten Jahre gab es einige viel versprechende Ergebnisse, die nahe legten, dass mit dem Elektroenzephalogramm (EEG) sowohl die Verarbeitung von Gesichtern, als auch der Mimik messbar ist. Somit wäre das EEG eine geeignete Methode den Prozess der Emotionsdekodierung bei schizophrenen Patienten zu untersuchen. Diese Arbeit untersucht folgende zwei Hauptfragestellungen. Erstens, wie lassen sich die für die Verarbeitung von Gesichtern und das Erkennen von emotionalen Gesichtsausdrücken verantwortlichen kognitiven Prozesse mit Hilfe ereigniskorrelierter Potentiale des EEGs reliabel messen? Zweitens, sind diese Prozesse bei schizophrenen Patienten im Vergleich zu gesunden Probanden beeinträchtigt? Zur Klärung der ersten Fragestellung wurden drei Stichproben gesunder Personen untersucht. Es zeigte sich in allen drei Untersuchungen, dass sich die Verarbeitung von Gesichtern im Vergleich zu Kontrollreizen in einer negativen Komponente um 170 ms über temporalen Elektrodenpositionen widerspiegelt (Gesichterpeak, N170). Die N170 konnte mit dem Quellenlokalisationsprogramm LORETA unter anderem im Gyrus Fusiformis, der entsprechenden Hirnregion für die Gesichtsverarbeitung, lokalisiert werden. Für die Dekodierung emotionaler Gesichtsausdrücke konnten keine wiederholbaren Effekte nachgewiesen werden. Im Weiteren wurde die Gesichtsverarbeitung bei schizophrenen Patienten untersucht. 22 als schizophren diagnostizierte Patienten wurden mit einer nach dem Alter, dem Geschlecht und dem Bildungsstatus angepassten Kontrollgruppe verglichen. In dieser Auswertung deutete sich bei schizophrenen Patienten ein Defizit in den frühen Verarbeitungsschritten von Gesichtern an. Dieses Ergebnis wurde in dieser Art noch nicht gezeigt und reiht sich ein in Studien, die sowohl strukturelle Veränderungen in den für die Gesichtsverarbeitung wesentlichen Hirnregionen bei schizophrenen Patienten zeigen konnten als auch ein allgemeines Defizit früher visueller Verarbeitung nahe legen. N2 - This study was based on the fact that schizophrenic patients show severe deficits in facial affect recognition and face processing but the affected processes are still unknown. Recent studies claimed that face processing as well as facial affect recognition can be measured with the electroencephalogram (EEG). Therefore this study had two main aims. First, we tried to measure face processing and facial affect recognition in a reliable manner in three independent samples of healthy controls. Secondly, we investigated whether these processes are impaired in schizophrenic patients. For face processing we replicated in all three samples the face specific N170 component, with higher negative amplitudes in the event-related potentials at 170 ms after face presentation. LORETA source localisation revealed higher activity for the N170 in the Gyrus Fusiformis, a region well known for face processing. For the facial affect recognition no reliable parameters could be reported. The comparison between 22 schizophrenic patients and 22 healthy controls revealed deficits in the N170 component and therefore for face processing in the group of patients. This result has not been reported before but is accordance with reduced volumes of the Gyrus Fusiformis in schizophrenic patients KW - Schizophrener KW - Mimik KW - Gesunder KW - Neurophysiologie KW - Emotionserkennung KW - Gesichtsverarbeitung KW - EEG KW - EKP KW - Schizophrenie KW - facial affect decoding KW - face processing KW - EEG KW - ERP KW - schizophrenia Y1 - 2003 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-8202 ER - TY - JOUR A1 - Rodrigues, Johannes A1 - Weiß, Martin A1 - Mussel, Patrick A1 - Hewig, Johannes T1 - On second thought … the influence of a second stage in the ultimatum game on decision behavior, electro-cortical correlates and their trait interrelation JF - Psychophysiology N2 - Previous EEG research only investigated one stage ultimatum games (UGs). We investigated the influence of a second bargaining stage in an UG concerning behavioral responses, electro-cortical correlates and their moderations by the traits altruism, anger, anxiety, and greed in 92 participants. We found that an additional stage led to more rejection in the 2-stage UG (2SUG) and that increasing offers in the second stage compared to the first stage led to more acceptance. The FRN during a trial was linked to expectance evaluation concerning the fairness of the offers, while midfrontal theta was a marker for the needed cognitive control to overcome the respective default behavioral pattern. The FRN responses to unfair offers were more negative for either low or high altruism in the UG, while high trait anxiety led to more negative FRN responses in the first stage of 2SUG, indicating higher sensitivity to unfairness. Accordingly, the mean FRN response, representing the trait-like general electrocortical reactivity to unfairness, predicted rejection in the first stage of 2SUG. Additionally, we found that high trait anger led to more rejections for unfair offer in 2SUG in general, while trait altruism led to more rejection of unimproving unfair offers in the second stage of 2SUG. In contrast, trait anxiety led to more acceptance in the second stage of 2SUG, while trait greed even led to more acceptance if the offer was worse than in the stage before. These findings suggest, that 2SUG creates a trait activation situation compared to the UG. KW - bargaining behavior KW - two-stage ultimatum game KW - reward positivity/FRN/MFN/N2 KW - trait activation in two-stage ultimatum game, KW - midfrontal theta KW - fairness evaluation vs. cognitive effort KW - EEG Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-318983 VL - 59 IS - 7 ER - TY - THES A1 - Ulrich, Natalie T1 - Processing of Near Outcomes and Outcome Sequences in Gambling: Implications for the Biopsychological Basis of Problem Gambling T1 - Verarbeitung von knappen Ergebnissen und Ergebnissequenzen im Glücksspiel : Implikationen für die biopsychologische Basis von problematischem Glücksspielverhalten N2 - Gambling is a popular activity in Germany, with 40% of a representative sample reporting having gambled at least once in the past year (Bundeszentrale für gesundheitliche Aufklärung, 2014). While the majority of gamblers show harmless gambling behavior, a subset develops serious problems due to their gambling, affecting their psychological well-being, social life and work. According to recent estimates, up to 0.8% of the German population are affected by such pathological gambling. People in general and pathological gamblers in particular show several cognitive distortions, that is, misconceptions about the chances of winning and skill involvement, in gambling. The current work aimed at elucidating the biopsychological basis of two such kinds of cognitive distortions, the illusion of control and the gambler’s and hot hand fallacies, and their modulation by gambling problems. Therefore, four studies were conducted assessing the processing of near outcomes (used as a proxy for the illusion of control) and outcome sequences (used as a proxy for the gambler’s and hot hand fallacies) in samples of varying degrees of gambling problems, using a multimethod approach. The first study analyzed the processing and evaluation of near outcomes as well as choice behavior in a wheel of fortune paradigm using electroencephalography (EEG). To assess the influence of gambling problems, a group of problem gamblers was compared to a group of controls. The results showed that there were no differences in the processing of near outcomes between the two groups. Near compared to full outcomes elicited smaller P300 amplitudes. Furthermore, at a trend level, the choice behavior of participants showed signs of a pattern opposite to the gambler’s fallacy, with longer runs of an outcome color leading to increased probabilities of choosing this color again on the subsequent trial. Finally, problem gamblers showed smaller feedback-related negativity (FRN) amplitudes relative to controls. The second study also targeted the processing of near outcomes in a wheel of fortune paradigm, this time using functional magnetic resonance imaging and a group of participants with varying degrees of gambling problems. The results showed increased activity in the bilateral superior parietal cortex following near compared to full outcomes. The third study examined the peripheral physiology reactions to near outcomes in the wheel of fortune. Heart period and skin conductance were measured while participants with varying degrees of gambling problems played on the wheel of fortune. Near compared to full outcomes led to increased heart period duration shortly after the outcome. Furthermore, heart period reactions and skin conductance responses (SCRs) were modulated by gambling problems. Participants with high relative to low levels of gambling problems showed increased SCRs to near outcomes and similar heart period reactions to near outcomes and full wins. The fourth study analyzed choice behavior and sequence effects in the processing of outcomes in a coin toss paradigm using EEG in a group of problem gamblers and controls. Again, problem gamblers showed generally smaller FRN amplitudes compared to controls. There were no differences between groups in the processing of outcome sequences. The break of an outcome streak led to increased power in the theta frequency band. Furthermore, the P300 amplitude was increased after a sequence of previous wins. Finally, problem gamblers compared to controls showed a trend of switching the outcome symbol relative to the previous outcome symbol more often. In sum, the results point towards differences in the processing of near compared to full outcomes in brain areas and measures implicated in attentional and salience processes. The processing of outcome sequences involves processes of salience attribution and violation of expectations. Furthermore, problem gamblers seem to process near outcomes as more win-like compared to controls. The results and their implications for problem gambling as well as further possible lines of research are discussed. N2 - Glücksspiel ist eine verbreitete Aktivität in Deutschland. 40% einer repräsentativen Stichprobe gaben an mindestens einmal im vergangenen Jahr um Geld gespielt zu haben (Bundeszentrale für gesundheitliche Aufklärung, 2014). Während die Mehrheit der Glücksspieler unbedenkliches Spielverhalten zeigt, entwickelt ein Teil der Spieler ernsthafte Probleme durch das Spielen, die das psychische Wohlergehen, sowie das soziale und Arbeitsleben beeinträchtigen. Nach aktuellen Schätzungen sind bis zu 0,8% der deutschen Bevölkerung von solch pathologischem Glücksspielen betroffen. Generell zeigen Menschen verschiedene kognitive Verzerrungen im Sinne falscher Einschätzungen der Gewinnwahrscheinlichkeit und der Beteiligung von Fähigkeiten in Bezug auf Glücksspiel. Dies trifft insbesondere für pathologische Glücksspieler zu. Das Ziel der vorliegenden Arbeit ist die Untersuchung der biopsychologischen Grundlagen zweier solcher kognitiver Verzerrungen, der Kontrollillusion sowie der Gambler’s Fallacy (bisweilen auch Spielerfehlschluss genannt) und Hot-Hand-Phänomene, sowie deren Modulation durch Glücksspielprobleme. Zu diesem Zweck wurden vier Studien durchgeführt, die die Verarbeitung knapper Ergebnisse (stellvertretend für die Kontrollillusion) und Ergebnissequenzen (stellvertretend für die Phänomene der Gambler’s Fallacy und Hot Hand) untersuchten. Dazu wurden Stichproben mit unterschiedlichem Schweregrad der Glücksspielproblematik sowie ein Multi-Methoden Ansatz verwendet. Die erste Studie untersuchte die Verarbeitung und Bewertung knapper Ergebnisse sowie das Wahlverhalten in einem Glücksrad Paradigma mittels Elektroenzephalographie (EEG). Um den Einfluss der Glücksspielproblematik zu erfassen, wurde eine Gruppe von Problemspielern mit einer Kontrollgruppe verglichen. Es zeigten sich keine Unterschiede in der Verarbeitung knapper Ergebnisse zwischen den beiden Gruppen. Im Vergleich zu vollen Ergebnissen führten knappe Ergebnisse zu kleineren Amplituden in der P300. Des Weiteren zeigte sich auf Trendniveau im Wahlverhalten der Probanden Anzeichen für ein der Gambler’s Fallacy entgegengesetztes Muster. Längere Sequenzen einer Ergebnisfarbe führten zu einer höheren Wahrscheinlichkeit diese Farbe im folgenden Durchgang erneut zu wählen. Schließlich zeigten Problemspieler relativ zur Kontrollgruppe kleinere Amplituden in der Feedbacknegativierung (FRN). Die zweite Studie zielte ebenfalls auf die Verarbeitung knapper Ergebnisse im Glücksrad Paradigma ab, allerdings unter Verwendung funktioneller Magnetresonanztomographie sowie einer Probandengruppe mit variierendem Ausmaß der Glücksspielproblematik. Es zeigte sich eine verstärkte Aktivierung im bilateralen superioren parietalen Cortex nach knappen im Vergleich zu vollen Ergebnissen. Die dritte Studie untersuchte peripherphysiologische Reaktionen auf knappe Ergebnisse im Glücksrad. Hierzu wurden Herzperiode und Hautleitfähigkeit erfasst während eine Probandengruppe mit unterschiedlichem Ausmaß an Glücksspielproblemen am Glücksrad spielte. Knappe Ergebnisse führten im Vergleich zu vollen Ergebnissen zu verlängerten Herzperioden kurz nach dem Ergebnis. Des Weiteren wurden die Herzperiodenreaktion und Hautleitfähigkeitsreaktion durch Glücksspielprobleme moduliert. Probanden mit einem hohem im Vergleich zu einem niedrigen Ausmaß an Glücksspielproblemen zeigten gesteigerte Hautleitfähigkeitsreaktionen auf knappe im Vergleich zu vollen Ergebnissen, sowie ähnliche Herzperiodenreaktionen auf knappe Ergebnisse und volle Gewinne. Die vierte Studie untersuchte das Wahlverhalten sowie Einflüsse vorheriger Sequenzen auf die Verarbeitung von Ergebnissen in einem Münzwurf Paradigma. Hierzu wurde ein EEG bei einer Gruppe von Problemspielern und Kontrollprobanden abgeleitet. Problemspieler zeigten wiederum generell kleinere FRN Amplituden als Kontrollen. Es zeigten sich keine Unterschiede in der Verarbeitung der Ergebnissequenzen zwischen den Gruppen. Die Unterbrechung einer Sequenz gleicher Ergebnisse führte zu verstärkter Power im Theta Frequenzband. Zusätzlich war die Amplitude der P300 nach zwei vorangegangenen Gewinnen erhöht. Schließlich zeigten Problemspieler im Vergleich zu Kontrollen die Tendenz das gewählte Symbol relativ zum vorangegangenen Ergebnissymbol häufiger zu wechseln. Zusammenfassend deuten die Ergebnisse auf Unterschiede in der Verarbeitung knapper und voller Ergebnisse hin, die vor allem Gehirnareale und Prozesse umfassen, die mit Aufmerksamkeit und Salienz assoziiert sind. Die Verarbeitung von Ergebnissequenzen umfasst Prozesse der Salienzzuschreibung und Erwartungsverletzung. Außerdem scheinen Problemspieler im Vergleich zu Kontrollen knappe Ergebnisse als gewinnähnlicher zu verarbeiten. Die Ergebnisse und deren Implikationen für problematisches Glücksspielverhalten sowie weitere mögliche Forschungsfragen werden diskutiert. KW - Spielsucht KW - Psychobiologie KW - Near Miss KW - Problem Gambling KW - Heart Period KW - EEG KW - fMRI KW - Gambler's Fallacy KW - Hot Hand Fallacy KW - Cognitive Distortions KW - Glücksspiel KW - Electroencephalographie KW - Funktionelle Kernspintomografie Y1 - 2016 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-139612 ER - TY - JOUR A1 - Real, Ruben G. L. A1 - Kotchoubey, Boris A1 - Kübler, Andrea T1 - Studentized continuous wavelet transform (t-CWT) in the analysis of individual ERPs: real and simulated EEG data N2 - This study aimed at evaluating the performance of the Studentized Continuous Wavelet Transform (t-CWT) as a method for the extraction and assessment of event-related brain potentials (ERP) in data from a single subject. Sensitivity, specificity, positive (PPV) and negative predictive values (NPV) of the t-CWT were assessed and compared to a variety of competing procedures using simulated EEG data at six low signal-to-noise ratios. Results show that the t-CWT combines high sensitivity and specificity with favorable PPV and NPV. Applying the t-CWT to authentic EEG data obtained from 14 healthy participants confirmed its high sensitivity. The t-CWT may thus be well suited for the assessment of weak ERPs in single-subject settings. KW - electroencephalogram KW - wavelet KW - EEG KW - t-CWT KW - significance KW - detection KW - ERP Y1 - 2014 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-113581 ER - TY - JOUR A1 - Stegmann, Yannik A1 - Andreatta, Marta A1 - Wieser, Matthias J. T1 - The effect of inherently threatening contexts on visuocortical engagement to conditioned threat JF - Psychophysiology N2 - Fear and anxiety are crucial for adaptive responding in life‐threatening situations. Whereas fear is a phasic response to an acute threat accompanied by selective attention, anxiety is characterized by a sustained feeling of apprehension and hypervigilance during situations of potential threat. In the current literature, fear and anxiety are usually considered mutually exclusive, with partially separated neural underpinnings. However, there is accumulating evidence that challenges this distinction between fear and anxiety, and simultaneous activation of fear and anxiety networks has been reported. Therefore, the current study experimentally tested potential interactions between fear and anxiety. Fifty‐two healthy participants completed a differential fear conditioning paradigm followed by a test phase in which the conditioned stimuli were presented in front of threatening or neutral contextual images. To capture defense system activation, we recorded subjective (threat, US‐expectancy), physiological (skin conductance, heart rate) and visuocortical (steady‐state visual evoked potentials) responses to the conditioned stimuli as a function of contextual threat. Results demonstrated successful fear conditioning in all measures. In addition, threat and US‐expectancy ratings, cardiac deceleration, and visuocortical activity were enhanced for fear cues presented in threatening compared with neutral contexts. These results are in line with an additive or interactive rather than an exclusive model of fear and anxiety, indicating facilitated defensive behavior to imminent danger in situations of potential threat. KW - anxiety KW - EEG KW - emotion KW - fear KW - heart rate KW - ssVEP Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-312465 VL - 60 IS - 4 ER -