Aufmerksamkeit auf visuelle Reize kann durch top-down Such- Strategien oder durch bottom-up Eigenschaften des visuellen Reizes gesteuert werden. Die Eigenschaft einer bestimmten Position, aus einer visuellen Szene heraus zu stechen, wird als Salienz bezeichnet. Es wird angenommen, dass auf neuronaler Ebene eine Salienzkarte existiert. Bis heute ist strittig, wo die Repräsentation einer solchen Karte im Gehirn lokalisiert sein könnte. Im Rahmen dieser Dissertation wurden drei Experimente durchgeführt, die verschiedene Aspekte von bottom-up Salienz-Verarbeitung mit Hilfe der funktionellen Magnetresonanztomographie untersuchten. Während die Aufmerksamkeit auf einen Fixationspunkt gerichtet war, wurde die neuronale Reaktion auf unterschiedlich saliente Stimuli in der Peripherie untersucht. In den ersten zwei Experimenten wurde die neuronale Antwort auf Orientierungskontrast und Luminanzkontrast untersucht. Die Ergebnisse deuten darauf hin, dass Salienz möglicherweise verteilt im visuellen System kodiert ist. Im dritten Experiment wurden natürliche Szenen als Stimuli verwendet. Im Einklang mit den Ergebnissen der ersten beiden Experimente wurde hier graduierte Salienz in frühen und späten visuellen Arealen identifiziert. Darüber hinaus konnten Informationen über die salientesten Positionen aus weiter anterior liegenden Arealen, wie dem anterioren intraparietalen Sulcus (aIPS) und dem frontalen Augenfeld (FAF), dekodiert werden. Zusammengenommen deuten die Ergebnisse auf eine verteilte Salienzverarbeitung von unterschiedlichen low-level Merkmalen in frühen und späten visuellen Arealen hin, die möglicherweise zu einer merkmalsunabhängigen Salienzrepräsentation im posterioren intraparetalen Sulcus zusammengefasst werden. Verschiebungen der Aufmerksamkeit zu den salientesten Positionen werden dann im aIPS und im FAF vorbereitet. Da die Probanden mit einer Fixationsaufgabe beschäftigt waren, wird die Salienz vermutlich automatisch verarbeitet. / Attention to visual stimuli can be guided by top-down search strategies or by bottom-up information. The property of a specific position to stand out in a visual scene is referred to as saliency. On the neural level, a representation of a saliency map is assumed to exist. However, to date it is still unclear where such a representation is located in the brain. This dissertation describes three experiments that investigated different aspects of bottom-up saliency processing in the human brain using functional magnetic resonance imaging (fMRI). Neural responses to different salient stimuli presented in the periphery were investigated while top-down attention was directed to the central fixation point. The first two experiments investigated the neural responses to orientation contrast and to luminance contrast. The results indicate that saliency is potentially encoded in a distributed fashion in the visual system and that a feature-independent saliency map is calculated late in the processing hierarchy. The third experiment used natural scenes as stimuli. Consistent with the results of the other two experiments, graded saliency was identified in striate and extrastriate visual cortex, in particular in posterior intraparietal sulcus (pIPS), potentially reflecting a representation of feature-independent saliency. Additionally information about the most salient positions could be decoded in more anterior brain regions, namely in anterior intraparietal sulcus (aIPS) and frontal eye fields (FEF). Taken together, the results suggest a distributed saliency processing of different low-level features in striate and extrastriate cortex that is potentially integrated to a feature-independent saliency representation in pIPS. Shifts of attention to the most salient positions are then prepared in aIPS and FEF. As participants were engaged in a fixation task, the saliency is presumably processed in an automatic manner.

Comprendre le comportement du système visuel rétino-thalamo-cortico-colliculaire (i.e. précoce) dans une situation d'images naturelles est d'une importance capitale pour comprendre ce qui se passe ensuite dans le cerveau. Pour comprendre ces comportements, les neurobiologistes ont étudié les voies standard, Parvocellulaires et Magnocellulaires, depuis des décennies. Cependant, il y a aussi la voie non-standard, ou Koniocellulaire, qui joue un rôle modulateur important dans les traitements local, global, et entremêlé, pour atteindre de tels comportements. Particulièrement, l'analyse standard du mouvement réalisée par la voie Magno est alternée avec des réactions rapides, comme la fuite ou l'approche à des mouvements spécifiques, qui sont pré-câblés dans la voie Konio. De plus, l'étude d'une tâche de fixation dans une situation réelle, par exemple quand un prédateur s'approche lentement de sa proie, implique non seulement un mécanisme de mouvement, mais nécessite également l'utilisation de la voie Parvo, qui analyse, au moins, le contraste de l'image. Ici, nous étudions dans un modèle neuronal de calcul bio-inspiré comment ces voies peuvent être modélisées avec un ensemble minimal de paramètres, afin de fournir des résultats numériques robustes lors d'une tâche réelle. Ce modèle repose sur une étude approfondie pour intégrer des éléments biologiques dans l'architecture des circuits, les constantes de temps et les caractéristiques de fonctionnement des neurones. Nos résultats montrent que notre modèle, bien que fonctionnant via des calculs locaux, montre globalement un bon comportement de réseau en termes d'espace et de temps, et permet d'analyser et de proposer des interprétations de l'interaction entre le thalamus et le cortex. À une échelle plus macroscopique, les comportements du modèle sont reproductibles et peuvent être qualitativement comparés à des mesures de fixation oculaire chez l'homme. Cela est également vrai lorsque l'on utilise des images naturelles, où quelques paramètres sont légèrement modifiés, en gardant des résultats qualitativement humains. Les résultats de robustesse montrent que les valeurs précises des paramètres ne sont pas critiques, mais leur ordre de grandeur l'est. Une instabilité numérique ne se produit qu'après une variation de 100% d'un paramètre. Nous pouvons donc conclure que cette approche systémique est capable de représenter les changements de l'attention en utilisant des images naturelles, tout en étant algorithmiquement robuste. Cette étude nous donne ainsi une interprétation possible sur le rôle de la voie Konio, tandis qu'en même temps elle nous permet de participer au débat sur les low et high-roads des flux attentionnel et émotionnel. Néanmoins, d'autres informations, comme la couleur, sont également présentes dans le système visuel précoce, et pourraient être prises en considération, ainsi que des mécanismes corticaux plus complexes, dans les perspectives de ce travail / Understanding the behavior of the retino-thalamo-cortico-collicular (i.e. early) visual system in a natural images situation is of utmost importance to understand what further happens in the brain. To understand these behaviors, neuroscientists have looked at the standard Parvocellular and Magnocellular pathways for decades. However, there is also the non-standard Koniocellular pathway, which plays an important modulating role in the local, global, and intermingled processing carried out to achieve such behaviors. Particularly, the standard motion analysis carried out by the Magno pathway is alternated with rapid reactions, like fleeing or approaching to specific motions, which are hard-wired in the Konio pathway. In addition, studying a fixation task in a real situation, e.g., when a predator slowly approaches its prey, not only involves a motion mechanism, but also requires the use of the Parvo pathway, analyzing, at least, the image contrast. Here, we study in a bio-inspired computational neural model how these pathways can be modeled with a minimal set of parameters, in order to provide robust numerical results when doing a real task. This model is based upon an important study to integrate biological elements about the architecture of the circuits, the time constants and the operating characteristics of the different neurons. Our results show that our model, despite operating via local computations, globally shows a good network behavior in terms of space and time, and allows to analyze and propose interpretations to the interplay between thalamus and cortex. At a more macroscopic scale, the behaviors emerging from the model are reproducible and can be qualitatively compared to human-made fixation measurements. This is also true when using natural images, where just a few parameters are slightly modified, keeping the qualitatively human-like results. Robustness results show that the precise values of the parameters are not critical, but their order of magnitude matters. Numerical instability occurs only after a 100% variation of a parameter. We thus can conclude that such a reduced systemic approach is able to represent attentional shifts using natural images, while also being algorithmically robust. This study gives us as well a possible interpretation about the role of the Konio pathway, while at the same time allowing us to participate in the debate between low and high-roads in the attentional and emotional streams. Nevertheless, other information, such as color, is also present in the early visual system, and should be addressed together with more complex cortical mechanisms in a sequel of this work

Erfolgreiches willkürliches Verhalten beruht auf der Selektion verhaltensrelevanter perzeptueller Informationen durch Aufmerksamkeit und deren kurzzeitiger Speicherung im Arbeitsgedächtnis. Bisherige Untersuchungen legen eine sowohl anatomische als auch funktionelle Interaktion beider kognitiver Funktionen nahe, insbesondere eine selektive Fazilitierung visueller Verarbeitung durch Arbeitsgedächtnisrepräsentationen. In der hier vorliegenden Arbeit wurde ein Gedächtnissakkadenparadigma (Gedächtnisphase von 6 Sekunden) mit einer visuellen Diskriminationsaufgabe kombiniert, die 1500, 2500 oder 3500 ms nach Präsentation des Gedächtnisstimulus durchzuführen war. Im Gegensatz zu den Erwartungen wurde eine transiente Verlängerung der Reaktionszeiten auf Diskriminationsstimuli beobachtet, die an aktuell erinnerten räumlichen Positionen präsentiert worden waren. In einem Kontrollexperiment ohne mnestische Anforderungen trat dieser Effekt hingegen nicht auf. Darüber hinaus hing die verzögerte Diskrimination von der Präzision der Gedächtnissakkaden und somit von der Güte der Arbeitsgedächtnisrepräsentation ab. Die räumliche Verteilung der Inhibition zeigte eine sog. „Center-Surround“-Organisation, wie sie für lokale neuronale Netzwerke im visuellen und präfrontalen Kortex bekannt ist. Es wird ein aktiver inhibitorischer Mechanismus postuliert, der den durch räumliches Arbeitsgedächtnis induzierten fazilitierenden Effekten entgegenwirkt und somit eine flexible Orientierung zu neuen Informationen während der Repräsentation von behavioral relevanten Informationen im räumlichen Arbeitsgedächtnis ermöglicht. Ein neurophysiologisches Korrelat für diesen Mechanismus könnte inhibitorische Gedächtnisphasenaktivität im präfrontalen Kortex darstellen, die über direkte präfrontotektale Projektionen vermittelt wird. / Voluntary behavior critically depends on attentional selection and short-term maintenance of perceptual information. Recent research suggests a tight coupling of both cognitive functions with visual processing being selectively enhanced by working memory representations. Here, a memoryguided saccade paradigm (6-s delay) was combined with a visual discrimination task, performed either 1,500, 2,500, or 3,500 ms after presentation of the memory cue. Contrary to what can be expected from previous studies, the results show that memory of spatial cues can transiently delay speeded discrimination of stimuli presented at remembered locations. This effect was not observed in a control experiment without memory requirements. Furthermore, delayed discrimination was dependent on the strength of actual memory representations as reflected by accuracy of memory-guided saccades. The spatial distribution of the observed discrimination inhibition showed a center-surround-organization reminiscent of activation patterns of local neuronal networks in prefrontal and visual cortex. An active inhibitory mechanism is proposed that counteracts facilitating effects of spatial working memory, promoting flexible orienting to novel information during maintenance of spatial memoranda for intended actions. Inhibitory delay-period activity in prefrontal cortex is a likely source for this mechanism which may be mediated by prefronto-tectal projections.

Submitted by Adriana Alves Rodrigues (aalves@espm.br) on 2018-10-09T18:35:23Z No. of bitstreams: 1 MPCC - MARIÂNGELA GALLINA.pdf: 2738383 bytes, checksum: 2dee930c11d516ee62ec9d342824ee72 (MD5) / Approved for entry into archive by Debora Cristina Bonfim Aquarone (deborabonfim@espm.br) on 2018-10-09T18:35:52Z (GMT) No. of bitstreams: 1 MPCC - MARIÂNGELA GALLINA.pdf: 2738383 bytes, checksum: 2dee930c11d516ee62ec9d342824ee72 (MD5) / Approved for entry into archive by Debora Cristina Bonfim Aquarone (deborabonfim@espm.br) on 2018-10-09T18:36:01Z (GMT) No. of bitstreams: 1 MPCC - MARIÂNGELA GALLINA.pdf: 2738383 bytes, checksum: 2dee930c11d516ee62ec9d342824ee72 (MD5) / Made available in DSpace on 2018-10-09T18:36:09Z (GMT). No. of bitstreams: 1 MPCC - MARIÂNGELA GALLINA.pdf: 2738383 bytes, checksum: 2dee930c11d516ee62ec9d342824ee72 (MD5) Previous issue date: 2018-03-28 / Research on visual attention and consumer behavior reports how packaging design raises interest and stimulates point of sale choice. However, little attention is dedicate to packaging, that has a similar layout or congruent. The empiricist of this dissertation evaluates the decision making of the consumer in front of a packaging with congruent layout between the brands of the same category of product. It divided into three studies, all performed in a retail laboratory environment and using eye tracking. Two studies were exploratory, being that the second was the inclusion of a controlled variable, the observation distance. The third was an experiment with hypothesis testing constructed from the previous results and supported in the literature review. The results of the study show a correspondence between the shelf position and consumer choice, regardless of the congruent factors and distance of observation. The inputs serve as a basis for future research, can be validated for other product categories, and subsidize marketing strategies and packaging design. / Pesquisas sobre atenção visual e o comportamento do consumidor relatam como o design de embalagem desperta o interesse e estimula a escolha no ponto de venda. No entanto, pouca atenção é dedicada às embalagens que apresentam layout similar ou congruentes. O empírico dessa dissertação avalia a tomada de decisão do consumidor frente a uma embalagem com layout congruente entre as marcas de uma mesma categoria de produto. Está dividido em três estudos, todos realizados em ambiente de laboratório de varejo e com uso de eye tracking. Dois estudos foram de caráter exploratório, e o segundo houve a inclusão de uma variável controlada, a distância de observação. O terceiro foi um experimento com teste de hipóteses construídas a partir dos resultados anteriores e apoiados na revisão da literatura. Os resultados do estudo mostram uma correspondência entre a posição de gôndola e a escolha do consumidor, independente da congruência e da distância de observação. Os inputs servem como base para futuras pesquisas, podem ser validados em outras categorias de produtos e subsidiar estratégias de marketing e design de embalagem.

RésuméL’objectif général de cette thèse était d’étudier les capacités d’empan visuo-attentionnel (VA) des lecteurs arabophones. Les recherches ont montré que l’empan VA module le traitement visuel des séquences de lettres et joue à ce titre un rôle important en lecture experte, tel que modélisé dans le cadre du modèle multitraces de lecture experte (Ans, Carbonnel et Valdois, 1998). Il a également été montré que l'empan VA joue un rôle dans l’acquisition de la lecture et qu’une réduction de l’empan VA explique certaines formes de dyslexies développementales. Néanmoins, les études menées jusqu’ici se sont limitées aux langues européennes. Il s’agissait donc d’évaluer la pertinence du concept d’empan VA dans une langue de structure très différente, comme l’arabe. Deux questions principales ont été abordées : la première (Etude 1) portait sur une éventuelle modulation des capacités d’empan VA selon la langue ; elle a été menée chez des lecteurs experts. La seconde (Etude 2) visait à évaluer l’implication de l’empan VA dans les troubles de l’apprentissage de la lecture. Dans l’étude 1, nous avons comparé les performances d’empan VA chez des adultes de langue française, espagnole et arabe. Nous montrons notamment que les capacités d’empan VA sont plus limitées chez les arabophones que chez les français ou les hispanophones. La taille de l’empan VA n’est pas modulée par la transparence de la langue mais pourrait varier selon les contraintes de traitement des mots (traitement parallèle pour le français et l’espagnol mais traitement privilégié de la racine morphologique pour l’arabe). L’étude 2 a porté sur des enfants arabophones de 4ème et 5ème année, bons et mauvais lecteurs, qui ont été soumis à des épreuves de lecture, de conscience phonologique et d’empan VA. Nous montrons que les capacités d’empan VA contribuent à expliquer les performances en lecture de mots et de texte, voyellé et non voyellé, indépendamment des capacités phonologiques des enfants. Comme dans les langues européennes, un sous-groupe d’enfants mauvais lecteurs présente un trouble isolé de l’empan VA. Par contre, la proportion d’enfants présentant un trouble de l’empan VA, isolé ou pas, est beaucoup plus importante que dans les études précédentes portant sur les langues européennes. Ces résultats devraient conduire à proposer de nouveaux outils de diagnostic et de remédiation des troubles d'apprentissage de la lecture chez les lecteurs arabophones. Ils ont également des implications potentielles sur les méthodes d’enseignement de la lecture en langue arabe. / AbstractThe aim of this doctoral research was to study the visual-attention (VA) span abilities of Arabic-readers. Previous studies showed that VA span modulates letter string visual processing and plays an important role in expert reading, as modeled in the multitrace memory model (Ans, Carbonnel and Valdois, 1998). The VA span was previously described as a key component of reading acquisition; a reduction in VA span was found to characterize a subgroup of children with developmental dyslexia. Longitudinal and training studies suggest this relation may be causal. However, all previous studies on VA span have been limited to the European languages. Our purpose in this doctoral research was to assess the relevance of the VA span in a language of very different structure, the Arabic language. Two main questions were addressed. In Study 1, we explored potential modulations of VA span skills depending on the language characteristics; this study was conducted on expert readers. Study 2 was designed to investigate the role of VA span in reading acquisition in Arabic children. In Study 1, we compared the VA span performance of skilled readers from three different languages (French, Spanish and Arabic). We show that VA span abilities are reduced in Arabic as compared to French or Spanish. Differences in the size of VA span do not relate to language transparency but may depend on orthographic processing constraints (parallel processing of the word letter string for French and Spanish but privileged processing of the morphological root for Arabic). Study 2 was carried out on Arabic-speaking children, good and poor readers, from 4th and 5th grade. They were administered tests of reading, phonological awareness and VA span. Results show that VA span abilities contribute to explain performance in word and text reading whatever the script (vowelized or not) regardless of the child phonological abilities. As in European languages, a subgroup of poor readers shows an isolated VA span disorder. However, the proportion of children with a VA span disorder (isolated or not) is much higher than in previous studies on European languages. The current findings should allow designing new diagnostic tools and remediation programs for Arabic children with learning disorders. They also have potential implications for the teaching methods of reading in Arabic.

Made available in DSpace on 2016-04-28T20:56:34Z (GMT). No. of bitstreams: 1 Renan de Almeida Sargiani.pdf: 1879594 bytes, checksum: 30d53cbb220f22cadcfb3ef6f994cefd (MD5) Previous issue date: 2013-01-29 / Conselho Nacional de Desenvolvimento Científico e Tecnológico / Earlier studies showed that reading performance depends on phonemic awareness skills and visual attention span (VAS). Phonemic awareness refers to sensitivity and intentional control over the smallest speech sounds, i.e., phonemes. Visual attention span refers to the amount of distinct visual elements (letters) that can be processed simultaneously within a given set. There are hardly any studies on these two skills and their role in reading performance among Brazilian Portuguese speakers. This study aims at verifying (1) the existence of relationships between the skills of VAS and phonemic awareness and their relations with the reading performance of Brazilian children and (2) whether these relations would modify during their schooling years. The sample was made up of 48 students (1st, 3rd and 5th grade) from a public elementary school in Sao Paulo (Brazil). Children were assessed in three sessions through a battery of tasks which included single word reading, phonemic awareness, VAS, nonverbal IQ, verbal short-term memory and letter identification threshold. Results showed that VAS and phonemic awareness correlated with performance in reading of regular and irregular words and nonwords from 1st to 5th grade of elementary school. They also indicated that VAS and phonemic awareness play a more important role at the beginning of the learning of reading, i.e., in 1st grade, but continue to be of importance to reading ability in 3rd and 5th grade especially in reading of nonwords. It was also observed that there is a development of reading skills, phonemic awareness and visual attention span with the progress in schooling / Estudos anteriores demonstraram que o desempenho em leitura depende das habilidades de consciência fonêmica e de amplitude visuo-atencional (AVA). A consciência fonêmica se refere à sensibilidade e controle intencional dos menores sons da fala, isto é, os fonemas. A amplitude visuo-atencional se refere à quantidade de elementos visuais distintos (letras) que podem ser processados simultaneamente dentro de um conjunto. Ainda são escassas as pesquisas sobre essas duas habilidades e seu papel no desempenho em leitura em falantes do português do Brasil. No presente estudo, verificou-se (1) a existência de relações entre as habilidades de AVA e de consciência fonêmica e o desempenho em leitura em crianças brasileiras e (2) se essas relações se modificavam com o progresso na escolarização. Participaram desse estudo 48 alunos do 1º ano, 3º ano e 5º ano do ensino fundamental de uma escola pública de São Paulo. As crianças foram avaliadas em três sessões por meio de uma bateria que incluía tarefas de leitura de palavras isoladas, tarefas de consciência fonêmica, tarefas de EVA, Q.I. não verbal, memória verbal de curto prazo e limiar de identificação de letras. Demonstrou-se que a AVA e a consciência fonêmica se correlacionam com o desempenho em leitura de palavras regulares, irregulares e pseudopalavras desde o 1º até o 5º ano do ensino fundamental. Os resultados indicam que a AVA e a consciência fonêmica desempenham um papel mais importante no 1º ano da aprendizagem da leitura, mas continuam tendo um papel relevante no 3º ano e no 5º ano principalmente na leitura de pseudopalavras. Observou-se também que ocorre uma evolução das habilidades de leitura, consciência fonêmica e amplitude visuoatencional com o progresso na escolarização

Existem evidências que jogar videogames de ação (AVG) aperfeiçoa habilidades perceptuais, atentivas e cognitivas, como por exemplo, recuperação mais rápida da atenção visual e aprimoramento das dinâmicas temporais da percepção visual. Estudos correlacionais sugerem que estes aprimoramentos temporais se aplicam também ao processamento visual de baixa ordem, contudo evidências mais contundentes são necessárias. Ademais, no campo da multimídia computacional estudos apontam que a resolução temporal na qual o videogame é apresentado na tela, correspondente a taxa de quadros por segundo (QPS), afeta o desempenho e o entretenimento de jogadores. Entretanto ainda não se sabe como aspectos técnicos dos AVG, como a taxa de QPS, influenciam nos aperfeiçoamentos cognitivos citados anteriormente. Para esclarecer tais lacunas, delineou-se um estudo para verificar se AVG jogados em diferentes QPS afetam a recuperação temporal da atenção, medidos pela tarefa de Supressão Atencional (SA), e se há alterações nos limiares da resolução temporal visual, medidas através da frequência crítica de fusão e oscilação da visão (CFF). Trinta e dois (16M, 16F) participantes não jogadores de videogame voluntariaram-se para um experimento longitudinal. Inicialmente os voluntários foram separados em quatro grupos (4M, 4F) e todos eles no primeiro dia foram submetidos a uma tarefa de mensuração de CFF na região visual central e uma tarefa de SA. No dia seguinte e depois nos sete dias conseguintes dois grupos, intitulados experimentais, realizaram um treinamento com videogames de ação, sendo que cada um dos grupos treinou em diferentes resoluções temporais, um a 15 QPS e outro a 120 QPS. Simultaneamente um terceiro grupo, treinou com um videogame controle sem elementos de ação. E o quarto grupo, controle, não teve treinamento. O total de tempo de treinamento foi de 10 horas, distribuído em 8 dias, exceto para o grupo sem treino. No dia posterior ao último dia de treinamento todos os participantes foram submetidos novamente a tarefas de SA e CFF. De modo geral o CFF aumentou para todos os participantes entre pré e pós-teste, particularmente para o grupo sem treino, não houve efeito de grupo. Desempenho no SA melhorou somente no para lag2 (212ms) para participantes que treinaram AVG na taxa de QPS mais baixa. Estes resultados sugerem que treinamento com AVG não aumenta o limiar do CFF na região visual central, se não o oposto, e que o aprimoramento temporal da atenção beneficia-se com um treinamento com AVG em baixa resolução temporal, mas não de alta taxa de QPS, ao menos nas 10 horas iniciais de treino / Action video game play enhances perceptual, attentional, and cognitive skills, such as leading to faster recovery of visual attention over time and improvement of temporal dynamics of visual perception. Correlational data suggest that these temporal enhancements extend to low-level vision processes, but stronger evidence is needed. Also, in the multimedia computing field it was pointed out that video game screen frame rate affects players performance and enjoyment, but it is unclear how such technical aspects of the games play a role in cognitive augmentations. To shed more light on these issues, we tested whether action video game play and the frame rate at which they are played affects flicker detection in the central visual field and performance in attentional blink task. Thirty two (16 M, 16F) non-video game players volunteered to a longitudinal experiment. They were randomly split into four groups (4M, 4F). All of the groups performed a critical flicker-fusion frequency task (by method of limits) and attentional blink task at the first day of the experiment. Two experimental groups underwent action video-game training with different screen frame-rate caps each (15 and 120 frames per second, respectively). And one control group trained with a control game and a second control group had no training. The total amount of time in video-game training was 10 hours (75 min per day for consecutive 8 days), except for the no-training group. On the 10th day, all participants performed the flicker-detection and attentional blink tasks (post-test). Generally, critical flicker-fusion thresholds increased at the post-test for all groups, particularly for the non-training group, there were no group effect. Only marginal increased were observed in lag 2 for participant trained in low-frame-rate action video games. Our data suggest that playing video games do not increase flicker sensitivity threshold, it may actually prevent increase. And lower frame rate training produce transfer effects to Attentional Blink task, but not the higher frame rate training, at least in the first 10 hours

A análise de cenas complexas por computadores não é uma tarefa trivial, entretanto, o cérebro humano pode realizar esta função de maneira eficiente. A evolução natural tem desenvolvido formas para otimizar nosso sistema visual de modo que apenas partes importantes da cena sejam analisadas a cada instante. Este mecanismo de seleção é denominado por atenção visual. A atenção visual opera sob dois aspectos: bottom-up e top-down. A atenção bottom-up é dirigida por conspicuidades baseadas na cena, como o contraste de cores, orientação, etc. Por outro lado, a atenção top-down é controlada por tarefas, memórias, etc. A atenção top-down pode ainda modular o mecanismo bottom-up através do enviesamento de determinadas características de acordo com a tarefa. Além do mecanismo de modulação considerado, o que é selecionado a partir da cena também representa uma importante parte para o processo de seleção. Neste cenário, diversas teorias têm sido propostas e podem ser agrupadas em duas linhas principais: atenção baseada no espaço e atenção baseada em objetos. Modelos baseados em objeto, ao invés de apenas direcionar a atenção para locais ou características específicas da cena, requerem que a seleção seja realizada a nível de objeto, significando que os objetos são a unidade básica da percepção. De modo a desenvolver modelos de acordo com a teoria baseada em objetos, deve-se considerar a integração de um módulo de organização perceptual. Este módulo pode segmentar os objetos do fundo da cena baseado em princípios de agrupamento tais como similaridade, proximidade, etc. Esses objetos competirão pela atenção. Diversos modelos de atenção visual baseados em objetos tem sido propostos nos últimos anos. Pesquisas em modelos de atenção visual têm sido desenvolvidas principalmente relacionadas à atenção bottom-up guiadas por características visuais primitivas, desconsiderando qualquer informação sobre os objetos. Por outro lado, trabalhos recentes têm sido realizados em relação ao uso do conhecimento sobre o alvo para influenciar a seleção da região mais saliente. Pesquisas nesta área são relativamente novas e os poucos modelos existentes encontram-se em suas fases iniciais. Aqui, nós propomos um novo modelo para atenção visual com modulações bottom-up e top-down. Comparações qualitativas e quantitativas do modelo proposto são realizadas em relação aos mapas de fixação humana e demais modelos estado da arte propostos / Perceiving a complex scene is a quite demanding task for a computer albeit our brain does it efficiently. Evolution has developed ways to optimize our visual system in such a manner that only important parts of the scene undergo scrutiny at a given time. This selection mechanism is named visual attention. Visual attention operates in two modes: bottom-up and top-down. Bottom-up attention is driven by scene-based conspicuities, such as the contrast of colors, orientation, etc. On the other hand, top-down attention is controlled by task, memory, etc. Top-down attention can even modulate the bottom-up mechanism biasing features according to the task. In additional to modulation mechanism taken into account, what is selected from the scene also represents an important part of the selection process. In this scenario, several theories have been proposed and can be gathered in two main lines: space-based attention and object-based attention. Object-based models, instead of only delivering the attention to locations or specific features of the scene, claim that the selection it be performed on object level, it means that the objects are the basic unit of perception. In order to develop models following object-based theories, one needs to consider the integration of a perceptual organization module. This module might segment the objects from the background of the scene based on grouping principles, such as similarity, closeness, etc. Those objects will compete for attention. Several object-based models of visual attention have been proposed in recent years. Research in models of visual attention has mainly focused on the bottom-up guidance of early visual features, disregarding any information about objects. On the other hand, recently works have been conducted regarding the use of the knowledge of the target to influence the computation of the most salient region. The research in this area is rather new and the few existing models are in their early phases. Here, we propose a new visual attention model with both bottom-up and top-down modulations. We provide both qualitative and quantitative comparisons of the proposed model against an ground truth fixation maps and state-of-the-art proposed methods

A análise de cenas complexas por computadores não é uma tarefa trivial, entretanto, o cérebro humano pode realizar esta função de maneira eficiente. A evolução natural tem desenvolvido formas para otimizar nosso sistema visual de modo que apenas partes importantes da cena sejam analisadas a cada instante. Este mecanismo de seleção é denominado por atenção visual. A atenção visual opera sob dois aspectos: bottom-up e top-down. A atenção bottom-up é dirigida por conspicuidades baseadas na cena, como o contraste de cores, orientação, etc. Por outro lado, a atenção top-down é controlada por tarefas, memórias, etc. A atenção top-down pode ainda modular o mecanismo bottom-up através do enviesamento de determinadas características de acordo com a tarefa. Além do mecanismo de modulação considerado, o que é selecionado a partir da cena também representa uma importante parte para o processo de seleção. Neste cenário, diversas teorias têm sido propostas e podem ser agrupadas em duas linhas principais: atenção baseada no espaço e atenção baseada em objetos. Modelos baseados em objeto, ao invés de apenas direcionar a atenção para locais ou características específicas da cena, requerem que a seleção seja realizada a nível de objeto, significando que os objetos são a unidade básica da percepção. De modo a desenvolver modelos de acordo com a teoria baseada em objetos, deve-se considerar a integração de um módulo de organização perceptual. Este módulo pode segmentar os objetos do fundo da cena baseado em princípios de agrupamento tais como similaridade, proximidade, etc. Esses objetos competirão pela atenção. Diversos modelos de atenção visual baseados em objetos tem sido propostos nos últimos anos. Pesquisas em modelos de atenção visual têm sido desenvolvidas principalmente relacionadas à atenção bottom-up guiadas por características visuais primitivas, desconsiderando qualquer informação sobre os objetos. Por outro lado, trabalhos recentes têm sido realizados em relação ao uso do conhecimento sobre o alvo para influenciar a seleção da região mais saliente. Pesquisas nesta área são relativamente novas e os poucos modelos existentes encontram-se em suas fases iniciais. Aqui, nós propomos um novo modelo para atenção visual com modulações bottom-up e top-down. Comparações qualitativas e quantitativas do modelo proposto são realizadas em relação aos mapas de fixação humana e demais modelos estado da arte propostos / Perceiving a complex scene is a quite demanding task for a computer albeit our brain does it efficiently. Evolution has developed ways to optimize our visual system in such a manner that only important parts of the scene undergo scrutiny at a given time. This selection mechanism is named visual attention. Visual attention operates in two modes: bottom-up and top-down. Bottom-up attention is driven by scene-based conspicuities, such as the contrast of colors, orientation, etc. On the other hand, top-down attention is controlled by task, memory, etc. Top-down attention can even modulate the bottom-up mechanism biasing features according to the task. In additional to modulation mechanism taken into account, what is selected from the scene also represents an important part of the selection process. In this scenario, several theories have been proposed and can be gathered in two main lines: space-based attention and object-based attention. Object-based models, instead of only delivering the attention to locations or specific features of the scene, claim that the selection it be performed on object level, it means that the objects are the basic unit of perception. In order to develop models following object-based theories, one needs to consider the integration of a perceptual organization module. This module might segment the objects from the background of the scene based on grouping principles, such as similarity, closeness, etc. Those objects will compete for attention. Several object-based models of visual attention have been proposed in recent years. Research in models of visual attention has mainly focused on the bottom-up guidance of early visual features, disregarding any information about objects. On the other hand, recently works have been conducted regarding the use of the knowledge of the target to influence the computation of the most salient region. The research in this area is rather new and the few existing models are in their early phases. Here, we propose a new visual attention model with both bottom-up and top-down modulations. We provide both qualitative and quantitative comparisons of the proposed model against an ground truth fixation maps and state-of-the-art proposed methods

Veränderungsblindheit tritt auf, wenn das Bewegungssignal einer Veränderung verdeckt wird oder der Betrachter von der Veränderung abgelenkt wird. In beiden Fällen kann die visuelle Aufmerksamkeit, mangels Hinweisreiz, nicht zum Ort der Veränderung gelenkt werden. Nach einer Erörterung von Augenbewegungen und ihrem Zusammenhang mit Veränderungsblindheit werden drei explorative Untersuchungen zur Veränderungsblindheit im Kontext des Straßenverkehrs vorgestellt. Untersuchung 1 befasst sich mit einem direkten Vergleich dreier unterschiedlicher Verdeckungsarten (Lidschläge, Blicksprünge, Blanks) bei statischem Stimulusmaterial (Fotos). Insgesamt führen die Ergebnisse zu dem Schluss, dass Veränderungsblindheit, unabhängig von der Verdeckungsart, ein Grund für zu spät oder nicht erkannte Gefahren im Straßenverkehr sein könnte, wenngleich sie für die gefährlichsten Situationen (relevante Additionen) am geringsten ausfällt und künstliche Blanks sich, zumindest in einer statischen Bedingung, gut zur Simulation von Lidschlägen und Sakkaden eignen. Darüber hinaus zeigen sich deutliche Hinweise zur impliziten Veränderungsentdeckung. Untersuchung 2 überprüft Teile von Untersuchung 1 in dynamischer Umgebung (Fahrsimulator) und findet überraschenderweise einen umgekehrten Effekt von Veränderungsblindheit. Die Echtheit des Effektes wird angezweifelt und auf die Nutzung von Abzählstrategien zurückgeführt. Unabhängig davon zeigen sich erneut Hinweise zur impliziten Entdeckung. Untersuchung 3 stellt schließlich einen direkten Vergleich zwischen statischer (Fotos) und dynamischer Umgebung (Filme) vor und zeigt, dass das Ausmaß an Veränderungsblindheit, unabhängig von Verdeckungsdauer und Veränderungsart, in dynamischer Umgebung größer ist als in statischer (85% vs. 64%) und daher eine Gefahr im Straßenverkehr darstellt. Wieder zeigen sich Hinweise auf eine implizite Entdeckung. Die Arbeit schließt mit einem grundlagen- und anwendungsorientierten Ausblick.