Estudamos os efeitos da estimulação elétrica no nucleus basalis magnocelular (Meynert), núcleo colinégico que projeta aferências para o córtex cerebral e tem sido associado a mecanismos de aprendizagem e memória. Verificamos os efeitos eletrofisiológicos induzidos pela estimulação elétrica do núcleo basalis pareado com apresentação de um tom puro. Caracterizamos a dinâmica da atividade elétrica neural do cortex auditivo primário e de núcleos subcorticais relacionados à circuitaria da aprendizagem e memória, durante o condicionamento auditivo nos momentos de aquisição e de revocação além correlacioná-las a dinâmica de freqüência cardiaca, variável que pode exprimir a relevância de um estímulo / Acetilcholine is related to learning and memory and is related to cortical activation. We studied the effects electrically stimulating the basal forebrain - the main cholinergic afferent to the cortex, while presenting paired and unpaired pure tones. Mathematical techniques were used to analyze electrophysiological data. The dynamics from primary auditory cortex and related subcortical nuclei were correlated to the auditory conditioning. We also correlated brain activity to the heart dynamics, considered a reliable measure of learning and conditioning, an interesting approach that uncovers the relevance of stimulus that is not detectable through other behavioral variables

INTRODUÇÃO: A Esclerose Múltipla é uma doença desmielinizante e autoimune, na qual ocorre a destruição da bainha de mielina por autoanticorpos. Esta destruição causa uma diminuição na velocidade de condução do impulso nervoso alterando, assim, as funções cerebral e neural. Para ocorrer o funcionamento adequado do sistema auditivo, tanto na sua porção periférica quanto na central há necessidade que o mesmo esteja íntegro. OBJETIVO: Este estudo tem como objetivo verificar a ocorrência de alterações nos potenciais evocados auditivos de curta (PEATE), média (PEAML) e longa (P300) latências em adultos audiologicamente normais com diagnóstico de Esclerose Múltipla do tipo remitente recorrente ou surto remissivo. MÉTODO: Para o grupo controle foram avaliados 25 indivíduos com histórico de desenvolvimento neurológico normal e sem queixa de zumbido, sendo 19 do gênero feminino e seis do masculino, com idade variando entre 25 e 55 anos (média de 35,16 anos de idade). Para o grupo pesquisa foram avaliados 25 indivíduos com Esclerose Múltipla do tipo remitente-recorrente ou surto-remissivo, seis do gênero masculino e 19 do feminino, com idades entre 25 e 53 anos (média de 34,88 anos de idade). Todos os indivíduos participantes da pesquisa realizaram audiometria tonal e vocal, medidas de imitância acústica e os potenciais evocados auditivos de curta, média e longa latências. RESULTADOS: Os resultados demonstraram ocorrência de alterações nos potenciais evocados auditivos de tronco encefálico e de média latência e no potencial cognitivo, em indivíduos com Esclerose Múltipla. Com relação ao potencial evocado auditivo de tronco encefálico, verificou-se aumento de latência das ondas III e V e dos interpicos I-III e I-V, sugerindo alteração de tronco encefálico baixo. No que diz respeito ao potencial evocado auditivo de média latência observou-se atraso nas latências das ondas Na e Pa e, para o potencial cognitivo, evidenciou-se aumento da latência do P300. Conclusão: Indivíduos com Esclerose Múltipla do tipo remitente recorrente apresentam alterações eletrofisiológicas observadas nos resultados dos potenciais evocados auditivos de curta e média latências e no potencial cognitivo, sugerindo comprometimento em diferentes locais do sistema nervoso auditivo central / INTRODUCTION: The Multiple Sclerosis is a demyelinating disease and autoimmune, which is the destruction of the myelin sheath of a selfantibodies. This destruction causes a decrease in impulse driving speed of nervous changing thus the brain and neural functions. To place the proper functioning of the auditory system, both in its peripheral portion as the central need that it is full. PURPOSE: This study aims to determine the occurrency of changes in auditory evoked potentials of short (PEATE), middle (PEAML) and long (P300) latencies in adults audiologically normal diagnosed with Multiple Sclerosis remitting type of applicant or remissive outbreak. METHOD: For the control group were evaluated 25 individuals with a history of normal neurological development and without complaint from tinnitus, and 19 females and six males, with ages ranging between 25 and 55 years (average of 35.16 years of age) . To search the group were evaluated 25 individuals with Multiple Sclerosis-remitting type of applicant or flareremissive, six males and 19 females, aged between 25 and 53 years (average of 34.88 years of age). All individuals participating in the search conducted tone audiometry and speech, acoustic immitance measures brainstem auditory evoked potential, middle latency response and cognitive potential RESULTS: The results showed occurrencies of changes in brainstem auditory evoked potential and middle latency and cognitive potential in individuals with Multiple Sclerosis. Regarding the potential of brain stem auditory evoked, there was an increase in latency wave III and V and interpeaks I-III and IV, suggesting change in brainstem down. Regarding the auditory evoked potential of average latency there was delay in latencies of Na and Pa waves, and the potential for cognitive, showed an increase of latency of P300. Conclusion: Individuals with multiple sclerosis relapsing remitting type of applicant presents electrophysiological changes seen in the results of sound evoked short and middle latency and the potential cognitive suggesting impairment from different parts of the central auditory nervous system

Introdução: No sistema auditivo, as mudanças decorrentes do envelhecimento resultam na dificuldade que os idosos apresentam em compreender a fala, afetando a capacidade de comunicação e de participação nas relações sociais, podendo levar à piora da qualidade de vida desta população. O treinamento auditivo é uma proposta de intervenção baseada na neuroplasticidade que tem o objetivo de adequar as habilidades auditivas de indivíduos com transtorno do processamento auditivo (TPA). Esse método vem sendo cada vez mais utilizado na reabilitação auditiva de idosos e, por meio de medidas comportamentais e eletrofisiológicas, revela-se como uma ferramenta eficaz para otimizar o processamento da fala, contribuindo para um processo de envelhecimento com qualidade de vida. Objetivos: Verificar a eficácia de um programa de treinamento auditivo acusticamente controlado (TAAC) em idosos com TPA utilizando medidas comportamentais e eletrofisiológicas. Método: Participaram 16 idosos (14 mulheres, dois homens) com TPA, os quais realizaram uma avaliação inicial (avaliação 1), composta por testes comportamentais e eletrofisiológicos do processamento auditivo, e foram distribuídos em dois grupos: GP (n=8), submetidos a um treinamento placebo e GSI (n=8) que não foram submetidos a nenhuma intervenção. Após 12 semanas os indivíduos foram submetidos novamente aos testes (avaliação 2 - pré TAAC). Em seguida, todos os indivíduos foram submetidos ao TAAC e após 12 semanas realizaram a avaliação final (avaliação 3 - pós TAAC). Resultados: Não houve diferença significante na análise multivariada entre as avaliações 1 e 2, tanto para os testes comportamentais quanto para o P300, sendo descartada a ocorrência de efeito placebo e efeitos teste-reteste. Na comparação entre as avaliações 2 e 3, foi constatada melhora significante entre as condições pré TAAC e pós TAAC para a maioria das habilidades auditivas investigadas pelo método comportamental; entretanto, o mesmo resultado não foi encontrado para os parâmetros do P300 em nenhuma das condições (tone burst ou fala). Também não foi encontrada diferença significante entre o P300 evocado por estímulo tone burst e o evocado por estímulo de fala no monitoramento das mudanças neurobiológicas decorrentes do TAAC. Conclusões: O TAAC foi capaz de promover uma mudança no desempenho comportamental dos idosos para a maioria das habilidades auditivas investigadas, mostrando ser um método eficaz na reabilitação auditiva de idosos com TPA. Considerando a grande vulnerabilidade aos fatores cognitivos e a variabilidade intra-sujeito que o P300 apresenta, concluímos que este potencial não parece ser a melhor ferramenta para monitorar as mudanças decorrentes do programa TAAC em idosos / Introduction: In the hearing system, changes from aging result in the difficulty that the elderly have understanding speech, affecting their communication abilities and their social participation in the community, which can lead to a decrease of life quality in this group of people. The auditory training is an intervention procedure based on neuroplasticity that aims improving hearing abilities of individuals with auditory processing disorder (APD). This method has been used in the auditory rehab of elderly and, through behavioral and electrophysiological measures, reveals itself as an effective tool for optimizing the processing of speech contributing for an aging process with life quality. Purpose: Verify the efficacy of an acoustically controlled auditory training program (ACAT) in elderly patients with APD using behavioral and electrophysiological measures. Method: Sixteen elderly (14 women, two men) with APD, who have performed an initial evaluation (1), consisting of behavioral and electrophysiological tests of auditory processing, were divided into two groups: GP (n = 8) those who were submitted to a placebo training and GSI (n = 8) the one\'s not submitted to any intervention. After 12 weeks the individuals were submitted to the tests again (evaluation 2 - pre ACAT). Then, all of them were submitted to ACAT and, after 12 weeks (8 training), they were submitted to the final evaluation (3 - post ACAT). Results: There was no significant difference in the various analyses between evaluations 1 and 2, both in the behavioral tests as for the P300, discarding the presence of placebo effects and test-retest. Comparing the evaluations 2 and 3, a significant improvement was found between the pre and post ACAT conditions for the majority of the auditory abilities investigated by the behavioral method; however, the same result was not found for the parameters of P300 in any of the conditions (tone burst or speech). The same way, no significant difference was found between the P300 evoked by tone burst and evoked by speech stimulation during the neurobiological changes monitoring coming from ACAT. Conclusions: The ACAT was able to promote a change in the behavioral performance of the elderly for most investigated auditory abilities, proving to be an effective method regards hearing rehabilitation of elderly with APD. Considering the high vulnerability to the cognitive factors and intra-subject variability that the P300 presents, we conclude that this potential does not seem to be the best tool to monitor the changes that result from the ACAT program in the elderly

Die emotionale Valenz von Wörtern beeinflusst deren kognitive Verarbeitung. Ungeklärt ist, obwohl von zentraler Bedeutung für die Disziplinen der Psycholinguistik und der Neurowissenschaften, die Frage nach dem funktionellen Lokus von Emotionseffekten in der visuellen Wortverarbeitung. In der vorliegenden Dissertation wurde mit Hilfe von Ereignis-korrelierten Potentialen (EKPs) untersucht, ob emotionale Valenz auf lexikalischen oder auf semantischen Wortverarbeitungsstufen wirksam wird. Vorausgegangene Studien weisen auf einen post-lexikalischen Lokus von Emotionseffekten hin, wobei einige wenige heterogene Befunde von sehr frühen Emotionseffekten auch einen lexikalischen Lokus vermuten lassen. In der vorliegenden Arbeit wurden drei emotions-sensitive EKP Komponenten beobachtet, die distinkte zeitliche und räumliche Verteilungen aufwiesen, und daher verschiedene Wortverarbeitungsstufen zu reflektieren scheinen. Die Ergebnisse wurden im Rahmen von allgemeinen Annahmen aktueller Wortverarbeitungs- und semantischer Repräsentationsmodelle diskutiert. Als zentrales Ergebnis kann benannt werden, dass Emotion am stärksten semantische Wortverarbeitungsstufen beeinflusste. Hieraus wurde geschlussfolgert, dass emotionale Valenz einen Teil der Wortbedeutung darstellt. Eine Interaktion mit einem lexikalischen Faktor sowie sehr frühe Emotionseffekte deuten auf einen zusätzlichen Lokus auf lexikalischen oder sogar perzeptuellen Wortverarbeitungsstufen hin. Dies bedeutet, Emotion veränderte die visuelle Wortverarbeitung auf multiplen Stufen, dabei konnten separate emotions-sensitive EKP Komponenten, die unterschiedlichen Randbedingungen unterliegen, mit jeweils einem frühen (pre-)lexikalischen und einem späten semantischen Lokus in der Wortverarbeitung in Verbindung gesetzt werden. Die Befunde stützen Wortverarbeitungsmodelle, die zeitlich flexible und interaktive Wortverarbeitungsstufen annehmen. / Emotional valence of words influences their cognitive processing. The functional locus of emotion effects in the stream of visual word processing is still elusive, although it is an issue of great importance for the disciplines of psycholinguistics and neuroscience. In the present dissertation event-related potentials (ERPs) were applied to examine whether emotional valence influences visual word processing on either lexical or semantic processing stages. Previous studies argued for a post-lexical locus of emotion effects, whereas a lexical locus has been indicated by a few heterogeneous findings of very early emotion effects. Three emotion-related ERP components were observed that showed distinct temporal and topographic distributions, and thus seem to reflect different processing stages in word recognition. Results are discussed within a framework of common assumptions from word recognition and semantic representation models. As a main finding, emotion impacted most strongly semantic processing stages. Thus, emotional valence can be considered to be a part of the meaning of words. However, an interaction of emotion with a lexical factor and very early emotion effects argued for an additional functional locus on lexical, or even on perceptual processing stages in word recognition. In conclusion, emotion impacted visual word processing on multiple stages, whereas distinct emotion-related ERP components, that are subject to different boundary conditions, were associated each with an early (pre-)lexical locus or a late semantic locus. The findings are in line with models of visual word processing that assume time-flexible and interactive processing stages, and point out the need for integration of word recognition models with models of semantic representation.

Emotionale Bedeutung erleichtert die Verarbeitung geschriebener Sprache. Dies zeigt sich sowohl in Verhaltensmaßen als auch in ereigniskorrelierten Potenzialen (EKPs) und resultiert vermutlich aus automatischer Aufmerksamkeitszuweisung auf Grund der hohen intrinsischen Relevanz von emotionalen Reizen. Die vorliegende Arbeit untersucht die Mechanismen von Emotionseffekten in geschriebener Sprache, insbesondere den Zeitverlauf der Emotionseffekte, die Beteiligung des peripheren Nervensystems, sowie die Rolle der Emotionsdimensionen Valenz und Erregung. Emotionseffekte in EKPs beginnen mit einer Latenz von 100 ms nach Stimulusonset. Dies deutet auf die Existenz eines schnellen und automatischen Erkennungssystems für emotionale Wörter hin. Zeitverlauf und Verteilung der Emotionseffekte weisen große Ähnlichkeit zu Befunden für emotionale Bilder auf und lassen auf ein domänenübergreifenden System zur Emotionserkennung schließen. Übereinstimmend mit dieser Annahme zeigen sich weitere Ähnlichkeiten in der Verarbeitung emotionaler Wörter und Bilder in einer Studie, die die Interaktion von stimulusbasierter Aufmerksamkeit und Emotion in der Wortverarbeitung untersuchte. Die Ergebnisse dieser Studie legen auf Grund des arbiträren Charakters von Schriftsprache den Schluss nahe, dass der Verarbeitungsvorteil für emotionale Reize zu einem geringeren Anteil als bisher vermutet auf biologischer Relevanz beruht. Neben diesen Ähnlichkeiten zeigt sich ein domänenspezifischen Unterschied in der Emotionsverarbeitung. Während die Darbietung emotionaler Bilder oft mit erhöhter Aktivierung des autonomen Nervensystems einhergeht, zeigen Befunde zur Pupillenaktivität, dass die Verarbeitung emotionaler Wörter nicht zwangsläufig zu autonomer Aktivierung führen muss; stattdessen scheint der Verarbeitungsvorteil für emotionale Wörter darauf zu beruhen, dass weniger kognitive Ressourcen für deren Verarbeitung notwendig sind. / Emotional meaning impacts the processing of written words, leading to facilitated processing that is visible not only in behavioral parameters, but also in event-related potentials (ERPs). It has been suggested that this processing benefit occurs because emotional stimuli involuntarily attract attention, possibly based on their higher intrinsic relevance. The present work investigates the conditions of emotion effects in word recognition, focusing on the time course of emotional processing, on the involvement of autonomic activation, and on contributions of emotional dimensions valence and arousal. In ERPs, emotion effects were evident from approximately 100 ms after stimulus onset, providing evidence for a fast and automatic detection and facilitation of emotional words. The time course and topography of emotion effects is in parallel to findings for affective pictures and suggests the existence of a common system for the extraction of emotional content across stimulus domains. In line with these findings, interactions of stimulus-triggered attention and emotion during word recognition are highly similar to interactions in picture processing. Due to the symbolic nature of words, this finding implies that emotion detection is less dependent on biological relevance than previously assumed. Apart from these analogies, the present results revealed a difference in emotional processing across stimulus domains. While affective pictures have frequently been reported to elicit augmented activity in the autonomic nervous system, evidence from pupillary responses indicates that emotional words do not mandatorily trigger autonomic activation. Instead, the processing advantage visible in behavioral measures seems to result from cognitive facilitation of emotional words.

In einer Pilotstudie sollten deutschsprachigen Probanden (n=28) in zwei Versuchsabschnitten kurze Sätze sprechen, die das Homonym "Leiter" im Sinne von "Steiggerät" bzw. "Teamchef" näher definieren. Das Homonym sollte am Satzanfang ohne Artikel genannt werden. Das Breitband-EEG (bis 2000 Hz, Zeitkonstante 1,5 s) wurde über F3, F4, C3 und C4 (Intern. 10-20-System) vor und kurz nach Sprachbeginn abgeleitet. Signalepochen des EEG- und Mikrophonsignals von 6 s Dauer wurden gespeichert. Off-line erfolgte die Auswertung der auf Sprachbeginn zentrierten und auf 1 Sekunde gekürzten EEG-Episoden. Es wurden vor Vokalisation motorische Bereitschaftspotentiale gefunden, die im gesamten Zeitbereich (750 ms prä- und 250 ms perireaktiv) wenig strukturiert sind und sich an den vier Ableitorten weder in ihrer Amplitude noch in ihrer Amplituden-Zeit-Struktur unterscheiden. Die Spektralanalyse der EEG-Signalstrecke zeigt unter beiden Versuchsbedingungen eine überproportional hohe Amplitude im [delta]-Band. Mit Hilfe der von Bartsch und Krüger entwickelten Subpotentialanalyse, die im Hochfrequenzbereich des EEG (10-400 Hz) dem "local field potential" ähnliche Phänomene nachweist, konnten in der Signalperiode des Bereitschaftspotentials positive und negative Subpotentiale ermittelt werden. Die Amplitude dieser Subpotentiale liegt zwischen 6 und 12[mycro]V. Der Zeitpunkt des Erscheinens der Subpotentiale wurde als Subpotentialevent (SPe) bezeichnet. Die SPe treten teils gruppiert und teils kohärent auf. Die Intervalle zwischen den SPe wurden histographisch aufgetragen, sie reichen vom 4 bis 15 ms. Auffallendstes Ergebnis war die unterschiedliche Struktur der SPe-Intervallhistogramme, die sich in den linksseitigen Ableitungen anders verhielten als in den rechtsseitigen. Möglicherweise sind diese Differenzen typisch für den eloquenten Unterschied. / During a pilot study, 28 german speeking subjects were supposed in two trial parts to speak in short sentences in order to define the german homonyme "Leiter" with the meaning "leader" respectively "manager". The homonyme should be used without any article at the beginning of the sentence. The EEG-activity (0-2000 Hz, time constant 1,5 sec) was recorded from F3, F4, C3 and C4 (international 10-20-system) before and after starting speech. Signalepochs of EEG-activity and microphone signals of 6 seconds were stored. The offline-evaluation was based on the centered and to the one second shortened EEG-episodes. Before staring speech there had been found a movement-related readines-potential (motor. Bereitschaftspotential), which had been less structured during the whole period of time (750ms pre- and 250 ms perireactive). Neither in their amplitude nor in their amplitude-time-structure distinctions were observed. The spectral analysis of EEG showed an overpropotional high amplitude in [delta]-band under both conditions of the trial. The subpotential-analysis developed by Bartsch and Krüger, which shows similar phenomenons as the "local field potentials" in the high frequency-EEG (10-400 Hz), could show positve and negative subpotentials during the period of the readiness-potential. The amplitudes of those subpotentials lay between 6 and 12[mycro]V. The point of time, when the subpotentials showed up, is called the subpotential-event (SPe). The SPe showed up partly in groups and partly coherent. The intervals between the SPe were put on histographically with a reach from 4 to 25 ms. The most striking result was the varying structure of the histography of the SPe-intervalls. The left-sided histography was conducted differently to the right-sided. May be that these distinctions are typical for the eloquent difference.

Empathische Reaktionen auf emotionale Gesichtsausdrücke werden vom Alter beeinflusst. In Bezug auf die kognitive Komponente der Empathie wurde eine Einschränkung bei der Erkennung emotionaler Gesichtsausdrücke sowohl für ältere Beobachter als auch für ältere Gesichter berichtet. Manche Studien berichten auch einen Effekt der Alterskongruenz, d.h. eine bessere Erkennung von Emotionen bei der eigenen Altersgruppe. Das erste Ziel der vorliegenden Dissertation war es, Mechanismen, die diesen Effekten zugrunde liegen könnten, zu untersuchen. Das zweite Ziel war es, zu untersuchen, ob auch die affektive Komponente der Empathie vom Alter beeinflusst wird. Studie 1 gibt einen Überblick über frühere Forschungsarbeiten. Studie 2 beschäftigte sich mit der Rolle von altersbezogenen Antwortverzerrungen, d.h. Altersunterschieden bei der Attribuierung bestimmter Emotionen. Effekte des Alters der Beobachter und der Gesichter auf die Erkennung von Trauer waren auf Antwortverzerrungen zurückzuführen. Allerdings trat eine bessere Erkennung von Trauer bei der eigenen Altersgruppe auf, die unabhängig von Antwortverzerrungen war. Studie 3 untersuchte neuronale Prozesse, die diesem Effekt der Alterskongruenz zugrunde liegen könnten. Bei traurigen Gesichtern wurde ein Effekt der Alterskongruenz für späte Verarbeitungsstadien gefunden, der möglicherweise eine höhere Relevanz trauriger Gesichter der eigenen Altersgruppe widerspiegelt. Studie 4 untersuchte, ob auch affektive Reaktionen, gemessen mit Gesichtsmimikry, vom Alter beeinflusst werden. Ältere Beobachter zeigten eine Beeinträchtigung in der Emotionserkennung, nicht jedoch in den affektiven Reaktionen. Insgesamt weisen diese Ergebnisse auf altersbezogene Defizite bei kognitiven und neuronalen Reaktionen hin; allerdings gab es kaum Alterseffekte auf affektive Reaktionen. Also lassen die Ergebnisse insgesamt trotz Schwierigkeiten bei der Emotionserkennung Optimismus bezüglich der intergenerationalen Empathie zu. / Empathic reactions to emotional facial expressions differ according to age. Concerning the cognitive component of empathy, decoding of emotional facial expressions was reported to be impaired both for older observers and older faces. Some studies also reported an own-age advantage, i.e., higher decoding accuracy for the own compared with other age groups. The first aim of the present dissertation was to explore possible mechanisms underlying these age effects. The second aim was to explore whether the affective component of empathy is affected by age as well. Study 1 summarizes previous research. Study 2 explored the role of age-related response bias, that is, age differences in the attribution of specific emotions. It showed that effects of the observers'' and the faces'' ages on decoding sadness were due to age-related response bias. However, an own-age advantage on decoding sadness occurred, which was independent of response bias. Study 3 explored the neurofunctional processes underlying this own-age advantage. It revealed an own-age effect on late processing stages for sadness, which may be due to an enhanced relevance of sad own-age faces. Study 4 explored whether affective responding in terms of facial mimicry is affected by age as well. It revealed an age-related decline in decoding accuracy, but not in affective responding. Taken together, these results suggest age-related deficits in cognitive and neural responses to emotional facial expressions. However, age had little influence on affective responding. Thus, despite difficulties in emotion decoding, these results allow for some optimism regarding intergenerational empathy.

Une interface cerveau-ordinateur permet d'interagir avec un système, comme un système d'écriture, uniquement par l'activité cérébrale. Un des phénomènes neurophysiologiques permettant cette interaction est le potentiel évoqué cognitif P300, lequel correspond à une modification du signal 300 ms après la présentation d'une information attendue. Cette petite réaction cérébrale est difficile à observer par électroencéphalographie car le signal est bruité. Dans cette thèse, de nouvelles techniques basées sur la théorie des ondelettes sont développées pour améliorer la détection des P300 en utilisant des mesures de similarité entre les canaux électroencéphalographiques. Une technique présentée dans cette thèse débruite les signaux en considérant simultanément la phase des signaux. Nous avons également étendu cette approche pour étudier la localisation du P300 dans le but de sélectionner automatiquement la fenêtre temporelle à étudier et faciliter la détection / Brain-Computer Interfaces (BCI) are control and communication systems which were initially developed for people with disabilities. The idea behind BCI is to translate the brain activity into commands for a computer application or other devices, such as a spelling system. The most popular technique to record brain signals is the electroencephalography (EEG), from which Event-Related Potentials (ERPs) can be detected and used in BCI systems. Despite the BCI popularity, it is generally difficult to work with brain signals, because the recordings contains also noise and artifacts, and because the brain components amplitudes are very small compared to the whole ongoing EEG activity. This thesis presents new techniques based on wavelet theory to improve BCI systems using signals' similarity. The first one denoises the signals in the wavelet domain simultaneously. The second one combines the information provided by the signals to localize the ERP in time by removing useless information

Gesichterkognition ist eine wichtige Fähigkeit für soziale Interaktionen. Obwohl große interindividuelle Unterschiede in der Gesichterkognition festgestellt wurden, gibt es bisher wenige Bestrebungen, diese Fertigkeit zu trainieren. In den vorliegenden Studien habe ich Trainingsverfahren für das Gesichtergedächtnis und die Geschwindigkeit der Gesichterkognition entwickelt und untersucht, welche auf dem Modell von Wilhelm et al. (2010) beruhen. In Studie 1 wurden Trainingseffekte bei gesunden Probanden mittleren Alters behavioral untersucht. Das Training des Gesichtergedächtnisses zeigte einen Trend zur Leistungsverbesserung in der trainierten Aufgabe. Das Training der Geschwindigkeit der Gesichterkognition verkürzte signifikant die Reaktionszeiten in allen Geschwindigkeitsaufgaben der Gesichterkognition, der Objektkognition sowie der mentalen Geschwindigkeit. Daher wird angenommen, dass das Geschwindigkeitstraining eine allgemeine Fähigkeit, komplexe visuelle Stimuli zu verarbeiten, beeinflusst hat. In Studie 2 wurden nach einem Re-Training die psychophysiologischen Grundlagen der trainingsbedingten Veränderungen untersucht. Das Geschwindigkeitstraining verkürzte zwar die Reaktionszeiten im Verlauf des Re-Trainings, jedoch unterschieden sich die beiden Trainingsgruppen nicht im folgenden Posttest. Die Auswertung der ereigniskorrelierten Potentiale wies auf eine Reduktion der strukturellen Repräsentationen aus dem Langzeitgedächtnis zur Erkennung von Individuen (N250r) durch das Geschwindigkeitstraining und auf eine Verstärkung der semantischen Verarbeitung von bekannten Gesichtern (N400) durch das Gedächtnistraining hin. Die vorliegende Arbeit zeigt die Plastizität der Verarbeitungsgeschwindigkeit für komplexe visuelle Stimuli auf. / Face cognition is a crucial skill for social interaction. Large individual differences in face cognition have been shown for healthy adults, suggesting that there might be a need for improvement, yet training of this ability has seldom been attempted. In the present studies, I developed and tested training procedures for face memory and for speed of face cognition, based on the model developed by Wilhelm et al. (2010). In Study 1, training effects were studied with healthy middle-aged participants at the behavioural level. Both training procedures enhanced performance over the course of the training. For facial speed, this improvement was significant as were the faster reaction times on all tasks for facial speed, for object speed, and for general processing speed. Thus, training of facial speed influenced a more general ability to process complex visual stimuli more quickly. Study 2 was conducted to investigate the psychophysiological underpinnings of training effects after a re-training. The facial speed training enhanced performance over the course of the re-training. In the post-test conducted directly after the re-training, the two groups did not differ in reaction times. Results within event-related components suggested that the facial speed training reduced the contributions of structural representations from long-term memory to identity recognition (N250r) and that face memory training enhanced the semantic processing of familiar faces (N400). This dissertation demonstrates the plasticity of the speed of processing complex visual stimuli. The versatility of the results and the limitations of the studies are discussed along with suggestions for future research.

Verhaltensstudien haben gezeigt, dass dynamische besser als statische Emotionsausdrücke erkannt werden. Im Einklang mit dieser dynamischer Vorteil Hypothese, haben fMRT Studien eine erhöhte und ausgedehnte Aktivierung für dynamische Emotionsausdrücke gezeigt. Die vorliegende Dissertation hatte das Ziel, die kognitiven Mechanismen, die den dynamischen Vorteil bedingen, zu klären, beziehungsweise die Spezifität dessen Wirkung für Gesichtsausdrücke der sechs Basisemotionen zu untersuchen. Studie 1 verglich Verhaltensdaten und kortikale Reaktionen zwischen dynamischen und statischen Emotionsausdrücken. Studie 2 behandelte methodischen Fragen des Timings der Stimuli und der neutralen dynamischen Bedingung. Studie 3 überprüfte die Hypothese, dass die Erhöhung der Menge von Bewegungen in den Gesichtsausdrücken die Zuweisung der Aufmerksamkeit erhöhen würde, und verglich die Wirkung in emotionalen und nicht-emotionalen Bewegungen. Study 4 konzentrierte sich auf die Frage der Emotionsspezifität der Hirnaktivierung in der Erkennung von Emotionen. Die Ergebnisse bestätigten einen dynamischen Vorteil in der Klassifizierung von Emotionsausdrücken, vermutlich bedingt durch eine Erhöhung in der visuellen Aufmerksamkeit, und eine Verbesserung der Wahrnehmungsverarbeitung. Außerdem, erhöht sich dieser Effekt mit allmählichem Erhöhen der Stärke der Bewegung in beide emotionalen und neutralen Bedingungen. Solche Effekte sprechen für ein perzeptuellen Bias erhöhte Aufmerksamkeit emotionalen verglichen mit neutralen und dynamischen verglichen mit statischen Gesichtern zuzuweisen. Dieser Effekt war für Freude etwas erhöht und für Überraschung reduziert, aber insgesamt ähnlich für alle Emotionsausdrücken. / Behavioral studies have shown that facial expressions of emotion unfolding over time provide some type of information that benefits the recognition of emotional expressions, in comparison with static images. In line with the dynamic advantage hypothesis, neuroimaging studies have shown increased and wider activation while seeing dynamic expressions. The present dissertation aims to clarify the cognitive mechanism underlying this dynamic advantage and the specificity of this effect for six facial expressions of emotion. Study 1 compared behavioral and brain cortical responses to dynamic and static expressions, looking for psychophysiological correlates of the dynamic advantage. Study 2 dealt with methodological issues regarding the timing of the stimuli and the dynamic neutral conditions. Study 3 tested the hypothesis that increasing the amount of movement in the expressions would increase the allocation of attention, and compared effects of intensity in both emotional and non-emotional movements. Study 4 focused on the question of emotion specificity of brain activation during emotion recognition. Results confirmed a dynamic advantage in the classification of expressions, presumably due to more efficient allocation of attention that improved perceptual processing. The effect increased gradually by augmenting the amount of motion, in both emotional and neutral expressions, indicating a perceptual bias to attend facial movements. The enhancement was somewhat larger for happiness and reduced for surprise, but overall similar for all emotional expressions.