Previous studies have found that behavioral and P300 responses to speech are influenced by linguistic cues in the stimuli. Research has found conflicting data regarding the influence of phonemic characteristics of stimuli in the mismatch negativity (MMN) response. The current investigation is a replication of the study designed by Tampas et al. (2005), which studied the effects of linguistic cues on the MMN response. This current study was designed to determine whether the MMN response is influenced by phonetic or purely acoustic stimuli, and to expand our knowledge of the scalp distribution of processing responses to within- and across-category speech and nonspeech stimuli. The stimuli used in this study consisted of within-category synthetic speech stimuli and corresponding nonspeech frequency glides. Participants consisted of 21 (11 male and 10 female) adults between the ages of 18 and 30 years. A same/different discrimination task was administered to all participants. Data from behavioral responses and event-related potentials (MMN and P300) were recorded. Results provided additional evidence that the MMN response is influenced by linguistic information. MMN responses elicited by the nonspeech contrasts had more negative peak amplitudes and longer latencies than MMN responses elicited by speech contrasts. Brain maps of t scores for speech vs. nonspeech contrasts showed significant differences in areas of cognitive processing for all contrast pairs over the left hemisphere near the temporal and parietal areas. The present investigation confirms that there are significant differences in the cortical processing of speech sounds vs. nonspeech sounds.

The mismatch negativity (MMN) response, a passively-elicited component of the auditory event-related potential (ERP), reflects preattentive identification of infrequent changes in acoustic stimuli. In the current study, the MMN response was examined closely to determine what extent natural speech sounds evoke the MMN. It was hypothesized that a significant MMN response results during the presentation of deviant stimuli from which spectral energy within formant bands critical to vowel identification has been removed. Localizations of dipoles within the cortex were hypothesized to yield information pertaining to the processing of formant-specific linguistic information. A same/different discrimination task was administered to 20 adult participants (10 female and 10 male) between the ages of 18 and 26 years. Data from behavioral responses and ERPs were recorded. Results demonstrated that the MMN may be evoked by natural speech sounds. Grand-averaged brain maps of ERPs created for all stimulus pairs showed a large preattentive negativity. Additionally, amplitudes of the MMN were greatest for pairs of auditory stimuli in which spectral energy not corresponding to formant frequencies was digitally eliminated. Dipoles reconstructed from temporal ERP data were located in cortical areas known to support language and auditory processing. Significant differences between stimulus type and reaction time were also noted. The current investigation confirms that the MMN response is evoked by natural speech sounds and provides evidence for a theory of preattentive formant-based processing of speech sounds.

The human brain is highly responsive to (deviant) sounds violating an auditory regularity. Respective brain responses are usually investigated in situations when the sounds were produced by the experimenter. Acknowledging that humans also actively produce sounds, the present event-related potential study tested for differences in the brain responses to deviants that were produced by the listeners by pressing one of two buttons. In one condition, deviants were unpredictable with respect to the button-sound association. In another condition, deviants were predictable with high validity yielding correctly predicted deviants and incorrectly predicted (mispredicted) deviants. Temporal principal component analysis revealed deviant-specific N1 enhancement, mismatch negativity (MMN) and P3a. N1 enhancements were highly similar for each deviant type, indicating that the underlying neural mechanism is not affected by intention-based expectation about the self-produced forthcoming sound. The MMN was abolished for predictable deviants, suggesting that the intention-based prediction for a deviant can overwrite the prediction derived from the auditory regularity (predicting a standard). The P3a was present for each deviant type but was largest for mispredicted deviants. It is argued that the processes underlying P3a not only evaluate the deviant with respect to the fact that it violates an auditory regularity but also with respect to the intended sensorial effect of an action. Overall, our results specify current theories of auditory predictive processing, as they reveal that intention-based predictions exert different effects on different deviance-specific brain responses.

The auditory system is able to recognize auditory objects and is thought to form predictive models of them even though the acoustic information arriving at our ears is often imperfect, intermixed, or distorted. We investigated implicit regularity extraction for acoustically intact versus disrupted six-tone sound patterns via event-related potentials (ERPs). In an exact-repetition condition, identical patterns were repeated; in two distorted-repetition conditions, one randomly chosen segment in each sound pattern was replaced either by white noise or by a wrong pitch. In a roving-standard paradigm, sound patterns were repeated 1–12 times (standards) in a row before a new pattern (deviant) occurred. The participants were not informed about the roving rule and had to detect rarely occurring loudness changes. Behavioral detectability of pattern changes was assessed in a subsequent behavioral task. Pattern changes (standard vs. deviant) elicited mismatch negativity (MMN) and P3a, and were behaviorally detected above the chance level in all conditions, suggesting that the auditory system extracts regularities despite distortions in the acoustic input. However, MMN and P3a amplitude were decreased by distortions. At the level of MMN, both types of distortions caused similar impairments, suggesting that auditory regularity extraction is largely determined by the stimulus statistics of matching information. At the level of P3a, wrong-pitch distortions caused larger decreases than white-noise distortions. Wrong-pitch distortions likely prevented the engagement of restoration mechanisms and the segregation of disrupted from true pattern segments, causing stronger informational interference with the relevant pattern information

L’objectif de ce travail était d’examiner la spécificité fonctionnelle du traitement et des représentations des hauteurs musicales. À cette fin, ce traitement a été comparé à celui des phonèmes de la parole, d’une part, et aux associations spatiales évoquées par des séquences ordonnées, d’autre part. Nos quatre études avaient pour point commun d’adapter à un nouvel objet de recherche des méthodes bien établies en psychologie cognitive. Ainsi, nous avons exploité la tâche de classification accélérée (Etude 1) de Garner (1974), l’analyse des conjonctions illusoires en mémoire (Etude 2), l’additivité de la composante mismatch negativity (MMN) des potentiels évoqués (Etude 3) et l’observation d’associations spatiales de codes de réponse (Etude 4). Les trois premières études, menées chez des participants non-musiciens, portaient sur la spécificité de traitement des hauteurs par rapport à celui des phonèmes au sein de stimuli chantés. Les deux premières études ont mis en évidence un effet surprenant de la nature des phonèmes sur leurs interactions avec le traitement des mélodies : les voyelles apparaissaient plus intégrées à la mélodie que les consonnes. Ceci était vrai à la fois lors du traitement en temps réel de non-mots chantés (Etude 1) et au niveau des traces en mémoire de ces mêmes non-mots (Etude 2, utilisant une tâche de reconnaissance à choix forcé permettant la mise en évidence de conjonctions illusoires). Cette dissociation entre voyelles et consonnes quant à leur intégration avec les traitements mélodiques ne semblait pas causée par des caractéristiques acoustico-phonétiques telles que la sonorité. Les résultats de la troisième étude indiquaient que les MMNs en réponse à des déviations de hauteur et de voyelle n’étaient pas additives et que leur distribution topographique ne différait pas selon le type de déviation. Ceci suggère que, même au niveau pré-attentionnel, le traitement des voyelles n’est pas indépendant de celui des hauteurs. Dans la quatrième étude, nous avons comparé le traitement des hauteurs musicales à un autre domaine : la cognition spatiale. Nous avons ainsi montré que les non-musiciens comme les musiciens associent les notes graves à la partie inférieure et les notes aiguës à la partie supérieure de l’espace. Les deux groupes liaient aussi les notes graves au côté gauche et les notes aiguës au côté droit, mais ce lien n’était automatique que chez les musiciens. Enfin, des stimuli musicaux plus complexes (intervalles mélodiques) n’évoquaient ces associations spatiales que chez les musiciens et ce, uniquement sur le plan horizontal. Ces recherches contribuent de plusieurs manières à la compréhension de la cognition musicale. Premièrement, nous avons montré que les consonnes et les voyelles diffèrent dans leurs interactions avec la musique, une idée à mettre en perspective avec les rôles différents de ces phonèmes dans l’évolution du langage. Ensuite, les travaux sur les représentations spatiales des hauteurs musicales ouvrent la voie à un courant de recherche qui aidera à dévoiler les liens potentiels entre habiletés musicales et spatiales. / The purpose of this work was to examine the functional specificity of musical pitch processing and representation. To this aim, we compared musical pitch processing to (1) the phonological processing of speech and (2) the spatial associations evoked by ordered sequences. The four studies described here all use classical methods of cognitive psychology, which have been adapted to our research question. We have employed Garner’s (1974) speeded classification task (Study 1), the analysis of illusory conjunctions in memory (Study 2), the additivity of the mismatch negativity (MMN) component of event-related potentials (Study 3), as well as the observation of spatial associations of response codes (Study 4). The three first studies examined, in non-musician participants, the specificity of pitch processing compared to phoneme processing in songs. Studies 1 and 2 revealed a surprising effect of phoneme category on their interactions with melodic processing: vowels were more integrated with melody than were consonants. This was true for both on-line processing of sung nonwords (Study 1) and for the memory traces of these nonwords (Study 2, using a forced-choice recognition task allowing the occurrence of illusory conjunctions). The difference between vowels and consonants was not due to acoustic-phonetic properties such as phoneme sonority. The results of the third study showed that the MMN in response to pitch and to vowel deviations was not additive and that its brain topography did not differ as a function of the kind of deviation. This suggests that vowel processing is not independent from pitch processing, even at the pre-attentive level. In the fourth study, we compared pitch processing to another domain: spatial cognition. We showed that both musicians and non-musicians map pitch onto space, in that they associate low-pitched tones to the lower spatial field and high-pitched tones to the higher spatial field. Both groups of participants also associated low pitched-tones with the left and high-pitched tones with the right, but this association was automatic only in musicians. Finally, more complex musical stimuli such as melodic intervals evoked these spatial associations in the horizontal plane only in musicians. This work contributes to the understanding of music cognition in several ways. First, we have shown that consonants and vowels differ in their interactions with music, an idea related to the contrasting roles of these phonemes in language evolution. Second, the work on the spatial representation of pitch opens the path to research that will help uncover the potential links between musical and spatial abilities.

La grossesse est un moment charnière de la vie où la femme reconsidère les bienfaits de chacune de ses habitudes de vie. Il est bien connu que l'activité physique apporte des bénéfices pour la cognition des enfants et des adultes, mais est-ce aussi le cas des femmes enceintes? Et qu'en est-il de l'enfant à naitre? L’objectif général de cette thèse était d’examiner l'effet de l'interaction entre l'activité physique et la grossesse sur les fonctions cognitives de la mère et de l'enfant. Une première étude démontre que la cognition de la femme enceinte diminue lors du troisième trimestre sans effet de condition physique. Une seconde étude présente les effets d'une séance d'activité physique sur plusieurs habiletés cognitives des femmes enceintes. On retrouve chez elles une diminution de la mémoire de travail et de la capacité d'attention soutenue alors qu'il n'y a pas d'effet chez la femme non enceinte. Enfin, une dernière étude présente l'impact de l'activité physique pratiquée tout au long de la grossesse sur le cerveau du nouveau-né. Cette étude démontre que les nouveau-nés de mères actives présentent des réponses neurophysiologiques plus matures que les enfants de mères sédentaires. L'ensemble de ces résultats démontre que la grossesse entraine des déficits cognitifs. De plus, les fonctions cognitives de la femme enceinte seront réduites à la suite d'une séance d'activité physique. Il serait donc préférable pour elle de ne pas prévoir son activité physique avant une activité qui nécessite ses capacités cognitives. Elle devrait tout de même effectuer de l'activité physique tout au long de sa grossesse afin d'offrir le meilleur départ possible dans la vie à son enfant. / Pregnancy is a pivotal moment in life when a woman reconsiders the value of each of her lifestyle choices. It is well known that physical activity brings benefits for cognition in children and adults, but is this also the case for pregnant women? What about their children? The overall objective of this thesis was to examine the effect of the interaction between physical activity and pregnancy on the cognitive functions of the mother and of the child. A first study shows that the cognition of pregnant women decreases during the third trimester and is not affected by their fitness level. A second study shows the effects of an exercise session on several cognitive abilities of pregnant women. We observed that pregnant women's self-monitoring ability is poorer than that of control women and that pregnant women's self-monitoring and sustained attention diminish after a bout of acute cardiovascular exercise. Finally, a third study shows the impact of physical activity performed throughout pregnancy on the brain of the newborn. This study demonstrates that newborns of active mothers have more mature neurophysiological responses than children of sedentary mothers. Taken together, these results demonstrate that pregnancy induces cognitive deficits. In addition, the cognitive functions of pregnant women are impaired as a result of an exercise session. Thus, they should not plan to exercise before a cognitively demanding activity. Nonetheless, women should still exercise regularly during pregnancy to provide the best possible start in life for their child.

The aim of the study was to examine central auditory processes compromised by age, age-related hearing loss, and the presentation of a distracting cafeteria noise using auditory event-related potentials (ERPs). In addition, the relation of ERPs to behavioral measures of discrimination was investigated. Three groups of subjects participated: young normal hearing, elderly subjects with normal hearing for their age, and elderly hearing-impaired subjects. Psychoacoustic frequency discrimination thresholds for a 1000-Hz pure tone were determined in quiet and in the presence of a contralateral cafeteria noise. To elicit ERPs, small frequency contrasts were presented with and without noise under unattended and attended conditions. In the attended condition, behavioral measures of d′ detectability and reaction times were also obtained. Noise affected all measures of behavioral frequency discrimination significantly. Except N1, all ERP components in the standard and difference waveforms decreased significantly in amplitude and increased in latency to the same degree in all three subject groups, arguing against a specific age-related sensitivity to the effects of contralateral background noise. For N1 amplitude, the effect of noise was different in the three subject groups, with a complex interaction of age, hearing loss, and attention. Behavioral frequency discrimination was not affected by age but deteriorated significantly in the elderly subjects with hearing loss. In the electrophysiological test, age-related changes occurred at various levels. The most prominent finding in the response to the standard stimuli was a sustained negativity (N2) following P2 in the young subjects that was absent in the elderly, possibly indicating a deficit in the inhibition of irrelevant information processing. In the attended difference waveform, significantly larger N2b and smaller P3b amplitudes and longer N2b and P3b latencies were observed in the elderly indicating different processing strategies. The pronounced age-related changes in the later cognitive components suggest that the discrimination of difficult contrasts, although behaviorally maintained, becomes more effortful in the elderly.

Το ακουστικό σύστημα έχει να μας διδάξει πολλά σχετικά με τις κεντρικές ακουστικές διαδικασίες, όμως ο τρόπος με τον οποίο συμπεριφέρεται και λειτουργεί σε διάφορα νοσήματα (αυτισμός, σ.Αsperger, σχιζοφρένεια), όσο και σε καταστάσεις τόσο προβληματικές (δυσλεξία, αλκοολισμός, κώμα) όσο και φυσιολογικές (εκμάθηση ξένων γλωσσών), είναι ακόμη άγνωστος. Ο λεπτός κρίκος που παρεμβάλλεται μεταξύ όλων αυτών των καταστάσεων και της λειτουργίας του ακουστικού συστήματος είναι ένα (ακουστικό) προκλητό δυναμικό, το αρνητικό δυναμικό ασυμφωνίας (ΑΔΑ). Το δυναμικό αυτό εκλύεται από τον εγκέφαλο οποτεδήποτε ένας διαφορετικός ήχος επιδράσει σε μια ακολουθία σταθερών ήχων. Πρόκειται για ένα αυτόματο φαινόμενο το οποίο υπάρχει στη φύση, είναι όμως δυνατό να εκλυθεί και να μελετηθεί και πειραματικά. Στην παρούσα εργασία αναλύεται το δυναμικό ΑΔΑ, περιγράφονται κάποιες κλινικές χρησιμότητες και μερικά πλεονεκτήματά του και αναλυτικά η μεθοδολογία και η πειραματική διάταξη που ακολουθήθηκε για την ανάδειξη του σημαντικού αυτού δυναμικού. Η πειραματική διάταξη που χρησιμοποιήθηκε στην παρούσα εργασία, επέτρεψε την ανίχνευση ισχυρών και διακριτών δυναμικών ΑΔΑ. Η διάταξη είναι εύκολα αναπαραγώγιμη και θα μπορούσε να τύχει πολλών κλινικών εφαρμογών. / By studying the function of the auditory system, it is possible to also elucidate the function of several central auditory procedures. It is however largely unknown how these are related to diseases such as autism, Asperger's syndrome, schizophrenia, but also to other situations such as dyslexia, coma, alcoholism, or the learning of foreign languages. The tiny bond that connects all these functions with central auditory processes is an auditory evoked potential called mismatch negativity (MMN). The MMN is elicited whenever a deviant sound interferes in a sequence of standard tones. Elicitation of MMN potentials is an automatic procedure that happens in nature all the time. It can however also be produced and detected in the laboratory. The present work starts with a detailed description of the MMN potential. Some of its advantages, as well as its clinical uses are also presented. This work also includes a very detailed description of the methhodology used to detect and study MMN potentials in experimental conditions. The experimental setup used in this work allowed us to detect substantial and discernible MMNs. This setup, and hence the study of MMNs is easily replicable, could therefore be also used in clinical praxis.

La grossesse est un moment charnière de la vie où la femme reconsidère les bienfaits de chacune de ses habitudes de vie. Il est bien connu que l'activité physique apporte des bénéfices pour la cognition des enfants et des adultes, mais est-ce aussi le cas des femmes enceintes? Et qu'en est-il de l'enfant à naitre? L’objectif général de cette thèse était d’examiner l'effet de l'interaction entre l'activité physique et la grossesse sur les fonctions cognitives de la mère et de l'enfant. Une première étude démontre que la cognition de la femme enceinte diminue lors du troisième trimestre sans effet de condition physique. Une seconde étude présente les effets d'une séance d'activité physique sur plusieurs habiletés cognitives des femmes enceintes. On retrouve chez elles une diminution de la mémoire de travail et de la capacité d'attention soutenue alors qu'il n'y a pas d'effet chez la femme non enceinte. Enfin, une dernière étude présente l'impact de l'activité physique pratiquée tout au long de la grossesse sur le cerveau du nouveau-né. Cette étude démontre que les nouveau-nés de mères actives présentent des réponses neurophysiologiques plus matures que les enfants de mères sédentaires. L'ensemble de ces résultats démontre que la grossesse entraine des déficits cognitifs. De plus, les fonctions cognitives de la femme enceinte seront réduites à la suite d'une séance d'activité physique. Il serait donc préférable pour elle de ne pas prévoir son activité physique avant une activité qui nécessite ses capacités cognitives. Elle devrait tout de même effectuer de l'activité physique tout au long de sa grossesse afin d'offrir le meilleur départ possible dans la vie à son enfant. / Pregnancy is a pivotal moment in life when a woman reconsiders the value of each of her lifestyle choices. It is well known that physical activity brings benefits for cognition in children and adults, but is this also the case for pregnant women? What about their children? The overall objective of this thesis was to examine the effect of the interaction between physical activity and pregnancy on the cognitive functions of the mother and of the child. A first study shows that the cognition of pregnant women decreases during the third trimester and is not affected by their fitness level. A second study shows the effects of an exercise session on several cognitive abilities of pregnant women. We observed that pregnant women's self-monitoring ability is poorer than that of control women and that pregnant women's self-monitoring and sustained attention diminish after a bout of acute cardiovascular exercise. Finally, a third study shows the impact of physical activity performed throughout pregnancy on the brain of the newborn. This study demonstrates that newborns of active mothers have more mature neurophysiological responses than children of sedentary mothers. Taken together, these results demonstrate that pregnancy induces cognitive deficits. In addition, the cognitive functions of pregnant women are impaired as a result of an exercise session. Thus, they should not plan to exercise before a cognitively demanding activity. Nonetheless, women should still exercise regularly during pregnancy to provide the best possible start in life for their child.

The mismatch negativity (MMN) is a specific event-related potential (ERP) component used frequently in the observation of auditory processing. The MMN is elicited by a deviant stimulus randomly presented in the presence of repeating stimuli. The current study utilized the MMN response in order to determine the temporal (timing) and linguistic processing of natural and synthetic vowel stimuli. It was hypothesized that a significant MMN response would be elicited by natural and synthetic vowel stimuli. Brain mapping of the MMN response was hypothesized to yield temporal resolution information, which would provide detail regarding the sequential processing differences between natural and synthetic vowel stimuli. It was also hypothesized that the location of dipoles within the cortex would provide information pertaining to differences in cortical localization of processing for natural and synthetic stimuli. Vowel stimuli were presented to twenty participants (10 females and 10 males between the ages of 18 and 26 years) in a three-forced-choice response paradigm. Data from behavioral responses, reaction times, and ERPs were recorded for each participant. Results demonstrated that there were differences in the behavioral and electrophysiological responses between natural and synthesized vowels presented to young, normal hearing adults. In addition, significant MMN responses were evoked by both natural and synthetic vowel stimuli. Greater reaction times existed for the synthetic vowel phonemes compared to the natural vowel phonemes. Electrophysiological differences were primarily seen in the processing of the synthetic /u/ stimuli. Scalp distribution of cognitive processing was essentially the same for naturally produced phonemes. Processing of synthetic phonemes also had similar scalp distributions; however, the synthetic /u/ phoneme required more complex processing compared to the synthetic /æ/ phoneme. The most significant processing localizations were located in the superior temporal gyrus, which is known for its role in linguistic processing. Continued processing in the frontal lobe was observed, suggesting continual evaluation of natural and synthetic phonemes throughout processing.