No description available.

No description available.

Temporally selective attention allows for the preferential processing of stimuli presented at particular times, and is reasoned to be important for processing rapidly presented information such as speech. Recent event-related potential (ERP) evidence demonstrates that listeners direct temporally selective attention to times that contain word onsets in speech. This may be an effective listening strategy since these moments provide critical information to the listener, but the mechanism that underlies this process remains unexplored. In three experiments, putative attention cues including word recognition and predictability were manipulated in both artificial and natural speech and ERP responses at various times were compared to determine how listeners selectively process word onsets in speech. The results demonstrate that listeners allocate attention to word-initial segments because they are less predictable than other times in the speech stream. Attending to unpredictable moments may improve spoken language comprehension by allowing listeners to glean the most relevant information from an otherwise overwhelming speech signal.

Speech perception in crowded acoustic environments is particularly challenging for hearing impaired listeners. While assistive hearing devices can suppress background noises distinct from speech, they struggle to lower interfering speakers without knowing the speaker on which the listener is focusing. The human brain has a remarkable ability to pick out individual voices in a noisy environment like a crowded restaurant or a busy city street. This inspires the brain-controlled hearing technologies. A brain-controlled hearing aid acts as an intelligent filter, reading wearers’ brainwaves and enhancing the voice they want to focus on. Two essential elements form the core of brain-controlled hearing aids: automatic speech separation (SS), which isolates individual speakers from mixed audio in an acoustic scene, and auditory attention decoding (AAD) in which the brainwaves of listeners are compared with separated speakers to determine the attended one, which can then be amplified to facilitate hearing. This dissertation focuses on speech separation and its integration with AAD, aiming to propel the evolution of brain-controlled hearing technologies. The goal is to help users to engage in conversations with people around them seamlessly and efficiently. This dissertation is structured into two parts. The first part focuses on automatic speech separation models, beginning with the introduction of a real-time monaural speech separation model, followed by more advanced real-time binaural speech separation models. The binaural models use both spectral and spatial features to separate speakers and are more robust to noise and reverberation. Beyond performing speech separation, the binaural models preserve the interaural cues of separated sound sources, which is a significant step towards immersive augmented hearing. Additionally, the first part explores using speaker identifications to improve the performance and robustness of models in long-form speech separation. This part also delves into unsupervised learning methods for multi-channel speech separation, aiming to improve the models' ability to generalize to real-world audio. The second part of the dissertation integrates speech separation introduced in the first part with auditory attention decoding (SS-AAD) to develop brain-controlled augmented hearing systems. It is demonstrated that auditory attention decoding with automatically separated speakers is as accurate and fast as using clean speech sounds. Furthermore, to better align the experimental environment of SS-AAD systems with real-life scenarios, the second part introduces a new AAD task that closely simulates real-world complex acoustic settings. The results show that the SS-AAD system is capable of improving speech intelligibility and facilitating tracking of the attended speaker in realistic acoustic environments. Finally, this part presents employing self-supervised learned speech representation in the SS-AAD systems to enhance the neural decoding of attentional selection.

No description available.

<p>Recent research on cognitive control has focused on the learning consequences of high selective attention demands in selective attention tasks. The current study extends these ideas by examining the influence of selective attention demands on remembering. In Experiment 1, participants read aloud the red word in a pair of red and green interleaved words. Half of the items were congruent (the interleaved words were the same), and the other half were incongruent (the interleaved words were different). Following the study phase, participants completed a recognition memory test with a remember/know classification. A mirror effect was observed in the recognition memory data, with better memory for incongruent than for congruent items. In Experiment 2, context was only partially reinstated at test, and again better memory for incongruent compared to congruent items was observed. However, the processes supporting recognition decisions varied depending on context reinstatement, with only full context reinstatement resulting in differences in recollection for congruent and incongruent items. These results demonstrate that selective attention process demands associated with incongruent items affect episodic learning.</p> / Master of Science (MSc)

Visual attentional capture is a form of visual attentional selection that is automatic and involuntary in nature, and is of high adaptive value as it allows visual attention to be oriented in a reflexive manner towards visual information without necessarily being guided by pre-existing knowledge, goals, and plans. According to the load-hypothesis (Lavie &amp; De Fockert, 2005), attentional capture of salient stimuli increases under load on working memory due to disruption of stimulus-processing priorities. Moreover, it has been proposed that maintenance of task-irrelevant verbal information increases distractor interference in singleton search by increasing attentional capture of salient, but task-irrelevant, color singletons. This hypothesis was tested in the present study by having participants complete several succeeding trials of singleton search while simultaneously maintaining digits in working memory. The presence of task-irrelevant color singletons in the search array of a singleton search task led to increased response times, indicating attentional capture. However, the cost to response times associated with distractor presence did not increase under load on working memory, indicating that distractor interference may not be affected by load on working memory when task-irrelevant verbal information is maintained over an extended period of time. Individual differences in action video game playing and trait anxiety were considered and excluded as possible confounders.

L’apprentissage des relations entre événements dans notre environnement nous permetd’anticiper des futures cibles et guide notre comportement. Une partie de cet apprentissage alieu sans intention, i.e. implicitement. Notre capacité limitée de traitement, qui contraste avec larichesse de notre environnement, impose la sélection d’une partie des informations sensorielles.Quels stimuli sont donc sélectionnés quand on apprend des associations ? Dans quelle mesurel’apprentissage sollicite des ressources attentionnelles ? Cette thèse porte sur les interactionsentre l’attention et l’apprentissage associatif.Dans la première partie expérimentale, nous avons étudié si la capture attentionnellependant l’apprentissage associatif est modulée par la prédictibilité de la cible. Nous avonsconçu 2 études EEG dans lesquels nous avons manipulé la valeur de la contingence entre indiceet cible. Nous avons trouvé deux biais attentionnels différents. Dans la première expérience lescibles inattendues ont montré une priorité attentionnelle, tandis que dans la deuxième ce sontles cibles prédictibles qui ont été privilégiées, y compris quand l’apprentissage est implicite.Ceux deux biais attentionnels, qui ont déjà été décrits en référence aux cibles dans des modèlesattentionnels de l’apprentissage, pourraient être au service de buts comportementaux différents.Dans la deuxième partie, nous avons étudié si les ressources attentionnelles disponiblesaffectent la capacité à discriminer des associations entre un indice et une cible. Pour cela nousavons mesuré la sensibilité aux associations sous différentes contraintes attentionnelles, à l’aided’un paradigme de double tâche. Nos données montrent que la discrimination est diminué parune tâche de suppression articulatoire concurrente et abolie par une tâche de charge cognitiveélevée. Bien qu’il ait été suggéré que l’apprentissage associatif puisse être automatique, nosdonnées montrent qu’il sollicite des ressources attentionnelles considérables. / Learning relations between events in our environment allows us to anticipate futureoutcomes and guides our decisions. Part of this learning occurs without intention, implicitly.Given the enormous amount of information available, which contrasts with our limitedprocessing capacity, the selection of certain stimuli becomes crucial. So which stimuli do weselect when we learn associations? How do the available attentional resources modulatelearning? This thesis focuses on the intertwining between associative learning and attention.In the first experimental part, we investigated whether the deployment of attentionduring associative learning is modulated by expectations. In particular, we conducted twoEEG studies in which we manipulated the contingent relation between a cue and an outcome.We found two different attentional biases. In the first experiment, unexpected outcomescaptured attention preferentially whereas predictable outcomes were prioritized in the second,and importantly even when the learning of the associations was implicit. We argue that theseattentional biases, which have already been described in attentional models of associativelearning, likely serve different goals.In the second experimental part, we examined to what extent associative learningrequires attention. With that aim, we measured sensitivity to contingency in three studiesunder different attentional constraints. Our data show that the ability to assess associations isdiminished by an articulatory suppression secondary task and is abolished by a highlydemanding task. While it has been suggested that associative learning might be an automaticprocess, our findings demonstrate that attention is critical to contingency assessment.

Atenção consiste em conjunto de processos que leva à seleção ou priorização no processamento de certas categorias de informação, em detrimento de outras, possibilitando um processamento mais eficiente do que seria possível caso o sistema nervoso processasse os estímulos presentes no ambiente simultaneamente. A atenção participa da maioria das funções cognitivas humanas. Depende, portanto, de região cerebral com privilégios anátomo-fisiológicos, como o lobo parietal, cujo padrão de conectividade (áreas unimodais, córtex pré-motor, colículo superior, giro cingulado, giro parahipocampal, insula, córtex orbitofrontal) possibilita a integração sensório-motora e cognitiva necessária à atenção. Desde o início da década de 80 estudos sobre o lobo parietal tem sugerido uma reavaliação de suas funções, modificando a percepção comum de que esteja relacionado exclusivamente a desempenhar funções espaciais, incluindo uma suposta especialização do lobo parietal direito na distribuição da atenção no espaço. No entanto, a base fisiológica para a especialização do lobo parietal na orientação atencional é mal compreendida pelas seguintes razões: 1- lesão unilateral do lobo parietal direito determina deficiência de processamento atencional em relação ao hemiespaço contralateral, e raramente ocorre após lesão do lobo parietal esquerdo; 2- o processamento das informações pelo sistema visual humano varia sensivelmente em relação aos campos visuais, e a metodologia dos testes atencionais tradicionais não considera que o desempenho dos voluntários pode ser limitado pela visibilidade dos estímulos; a localização dos estímulos tem sido avaliada independentemente da disposição dos alvos no campo visual. Nossa proposta é padronizar as condições de estimulação no teste de Posner para orientação da atenção, considerando os limiares específicos de cada voluntário e avaliar as deficiências de orientação da atenção endógena e exógena nos planos horizontal, vertical e diagonal, em pacientes portadores de dano nos lobos parietais direito e esquerdo, secundário a neoplasia, e compará-las entre si e com voluntários saudáveis. Desse modo poderíamos contribuir para o conhecimento sobre as bases neurais da atenção e para o desenvolvimento de estratégias eficazes e individualizadas de reabilitação / Attention consists of processes that lead to selection or prioritization in processing certain categories of information over others, allowing more efficient processing than would be possible if the nervous system had to process the stimuli in the environment simultaneously. Attention integrates most of human cognitive functions. Therefore it depends on specific brain regions with anatomical and physiological privileges, such as the parietal lobe, which pattern of connectivity (unimodal areas, premotor cortex, superior colliculus, cingulate gyrus, parahippocampal gyrus, insula, orbitofrontal cortex) enables sensorimotor and cognitive integration required for attention. Since early of 1980´s the common perception that parietal lobe is related solely to performance of spatial tasks, including a supposed specialization of the right parietal lobe for the distribution of attention in space is changing. The physiological basis for the specialization of the parietal lobe in orienting of attention is poorly understood for the following reasons: 1 - unilateral lesion of the right parietal lobe attentional determines disability in attention processing of information which comes from the contralateral space, and rarely occurs after injury of the left parietal lobe 2 - the processing of information by the human visual system varies considerably in relation to visual fields, and traditional attentional testing methodology does not consider that performance of the volunteers may be limited by the visibility of the stimuli; the location of the stimuli has been evaluated independently on the targets position in the visual field. Our proposal is to standardize the conditions of stimulation in the Posner test for orienting of attention, considering the specific visual thresholds of each subject and evaluate exogenous and endogenous orientation of attention deficiencies in horizontal, vertical and diagonal plans, in patients with damage to the right and left parietal lobes, secondary to brain tumor, and compare them among themselves and with healthy volunteers. Thereby this approach could contribute for the knowledge about the neural bases of attention and therefore help to develop effective strategies for rehabilitation

Investigamos, no Experimento, se o estímulo precedente, que captura a atenção quando existem demarcações, deixa de capturar a atenção na ausência de demarcações por ter seu processamento filtrado precocemente. Além disso, investigamos, nos experimentos 2, 3 e 4, se alterações no fundo da tela, que gerassem maior competição no processamento dos estímulos presentes na cena visual, poderiam levar à captura da atenção, mesmo sem a presença das demarcações classicamente utilizadas. Observamos que quando a intensidade dos estímulos competidores presentes na tela era alta, o estímulo precedente passou a capturar a atenção. Explicamos esse resultado com a hipótese de que as demarcações são importantes por adicionarem ruído ao processamento dos estímulos apresentados, influenciando a representação desses estímulos e, portanto, a possibilidade de um estímulo capturar a atenção. Por fim, no Experimento 5, investigamos se os resultados da tarefa de escolha de local seriam replicados em uma tarefa de discriminação de forma. / In Experiment 1 we investigated if a peripheral stimulus, which is able to capture attention when there are placeholders on the screen, is no longer able to capture attention in the absence of placeholders because is early filtered. In Experimento 2, 3 and 4 we investigated if changes on screen background, which would generate stronger processing competition between stimuli, could lead to attentional capture even in absence of placeholders. Accorging to our results the peripheral stimuli is able to capture attention when competing stimuli of high intensity are presented togueter on screen. Our explanation is that placeholders are important because they add noise to stimuli processing, affecting stimuli representation and, therefore, the probability that a stimulus will capture attention. Lastly, in Experimento 5 we investigated if similar results would be obtained in a form discrimination task.