Visual scanning of social stimuli in preterm and autism spectrum disorder children / Varredura visual de estímulos sociais em crianças prematuras e com transtorno do espectro autista

ABSTRACT Objective: To evaluate the pattern of eye-gaze of preterm (PT), autism spectrum disorder (ASD) and neurotypical (Ty) children. Methods: A cross-sectional study with eight preterm (born with ≤2000 g weight), nine ASD and five Ty male children, between six and nine years old, was performed. The eye gaze was evaluated presenting a board with a couple in social interaction, and a video with four children playing with blocks, projected in a screen computer, successively, evaluating the time that the children looked at each stimulus. Results: Although all the groups focus on the central social figure with no significant differences, ASD presented significant differences in time fixation of the objects (p=0.021), while premature children fixated more time in the central social interaction than in the whole scene than typical children. Conclusions: Although this study found noteworthy differences in the eye-gaze patterns among the three groups, additional research with a more extensive participant pool is necessary to validate these preliminary results.

RESUMO Objetivo: Avaliar o padrão de fixação visual de crianças nascidas prematuras (PT), com transtorno do espectro do autismo (TEA/ASD) e neurotípicas (Ty). Métodos: Estudo transversal incluindo oito meninos prematuros (nascidos com peso ≤2000 g), nove TEA e cinco Ty, com idade entre 6 e 9 anos. A varredura visual foi avaliada apresentando-se imagem de casal em interação social e vídeo com crianças brincando. A figura e o vídeo foram projetados em tela de computador, sucessivamente, sendo avaliado o tempo de fixação para cada estímulo. Resultados: Apesar de os três grupos de crianças focarem o olhar na figura social central sem diferenças significativas, crianças com TEA apresentaram diferenças significativas no tempo de fixação em objetos (p=0,021), enquanto prematuros fixaram o olhar mais tempo na interação social central do que na cena como um todo. Conclusões: Embora tenham sido notadas algumas diferenças significativas nos padrões de olhar para os três grupos, é necessário realizar mais pesquisas com uma amostra maior para confirmar esses resultados iniciais.

Visual Traces of Language Acquisition in Toddlers with Autism Spectrum Disorder During the Second Year of Life.

Infants show shifting patterns of visual engagement to faces over the first years of life. To explore the adaptive implications of this engagement, we collected eye-tracking measures on cross-sectional samples of 10-25-month-old typically developing toddlers (TD;N = 28) and those with autism spectrum disorder (ASD;N = 54). Concurrent language assessments were conducted and relationships between visual engagement and expressive and receptive language were analyzed between groups, and within ASD subgroups. TD and ASD toddlers exhibited greater mouth- than eye-looking, with TD exhibiting higher levels of mouth-looking than ASD. Mouth-looking was positively associated with expressive language in TD toddlers, and in ASD toddlers who had acquired first words. Mouth-looking was unrelated to expressive language in ASD toddlers who had not yet acquired first words.

Early developmental changes in visual social engagement in infant rhesus monkeys.

Impairments in social interaction in Autism Spectrum Disorder (ASD) differ greatly across individuals and vary throughout an individual's lifetime. Yet, an important marker of ASD in infancy is deviations in social-visual engagement, such as the reliably detectable early deviations in attention to the eyes or to biological movement (Klin et al., 2015). Given the critical nature of these early developmental periods, understanding its neurobehavioral underpinnings by means of a nonhuman primate model will be instrumental to understanding the pathophysiology of ASD. Like humans, rhesus macaques 1) develop in rich and complex social behaviors, 2) progressively develop social skills throughout infancy, and 3) have high similarities with humans in brain anatomy and cognitive functions (Machado and Bachevalier, 2003). In this study, male infant rhesus macaques living with their mothers in complex social groups were eye-tracked longitudinally from birth to 6 months while viewing full-faced videos of unfamiliar rhesus monkeys differing in age and sex. The results indicated a critical period for the refinement of social skills around 4-8 weeks of age in rhesus macaques. Specifically, infant monkeys' fixation to the eyes shows an inflection in developmental trajectory, increasing from birth to 8 weeks, decreasing slowly to a trough between 14-18 weeks, before increasing again. These results parallel the developmental trajectory of social visual engagement published in human infants (Jones & Klin, 2013) and suggest the presence of a switch in the critical networks supporting these early developing social skills that is highly conserved between rhesus macaque and human infant development.

Visual scanning preferences in low birth weight preterm infants / Preferências de rastreamento visual em prematuros nascidos com baixo peso

Abstract Introduction Few studies have used eye tracking as a screening tool for autism spectrum disorder (ASD) in preterm infants. Objectives To evaluate fixation time on social and non-social figures and percentage of preterm babies who gazed at the images. Methods This was a cross-sectional study of 31 preterm infants born weighing ≤ 2,000 g in which eye gaze was evaluated at 6 months of corrected age. Six boards with social and non-social figures were projected on a computer screen, successively, evaluating time and percentage of preterm babies who gazed at each board. The Modified Checklist for Autism in Toddlers (M-CHAT) was answered at 18 months of corrected age. Results Preterm infants showed longer visual fixation time on social figures compared with non-social images, regardless of the position of the social figure on the board. Similar percentages of preterm infants gazed either at social or non-social figures, at social figures with a direct or an indirect look, and at the eyes or mouth of the social figures. No preterm infant screened positive on the M-CHAT. Conclusion At 6 months of corrected age, preterm infants show the ability to gaze in an eye-tracking test, with preference for social figures, suggesting that this tool could be useful as another screening instrument for ASD.

Resumo Introdução Poucos estudos utilizaram a varredura visual como ferramenta para rastreamento de transtorno do espectro do autismo (TEA) em bebês prematuros. Objetivos Avaliar bebês prematuros quanto ao o tempo de fixação de olhar em figuras sociais e não sociais e a porcentagem deles que olharam para as imagens. Métodos Este estudo transversal incluiu 31 bebês prematuros com ≤ 2.000 g ao nascer, cujo rastreamento visual foi avaliado aos 6 meses de idade corrigida. Seis pranchas com figuras sociais e não sociais foram projetadas em tela de computador, sucessivamente, avaliando-se o tempo e porcentagem de prematuros que olharam para cada prancha. O Modified Checklist for Autism in Toddlers (M-CHAT) foi respondido aos 18 meses de idade corrigida. Resultados Os bebês prematuros apresentaram maior tempo de fixação visual em figuras sociais do que não sociais, independentemente da posição da figura social na prancha. Porcentagens similares de prematuros olharam tanto para figuras sociais como para não sociais, para figuras sociais com olhar direto ou indireto, e para boca ou olhos das figuras sociais. Nenhum prematuro foi rastreado positivamente pelo M-CHAT. Conclusão Aos 6 meses de idade corrigida, prematuros apresentaram habilidade para varredura em teste de rastreamento visual, com preferência por figuras sociais, sugerindo que esta ferramenta pode ser útil como mais um instrumento para rastreamento de TEA.

Early Developmental Trajectories of Functional Connectivity Along the Visual Pathways in Rhesus Monkeys.

Early social interactions shape the development of social behavior, although the critical periods or the underlying neurodevelopmental processes are not completely understood. Here, we studied the developmental changes in neural pathways underlying visual social engagement in the translational rhesus monkey model. Changes in functional connectivity (FC) along the ventral object and motion pathways and the dorsal attention/visuo-spatial pathways were studied longitudinally using resting-state functional MRI in infant rhesus monkeys, from birth through early weaning (3 months), given the socioemotional changes experienced during this period. Our results revealed that (1) maturation along the visual pathways proceeds in a caudo-rostral progression with primary visual areas (V1-V3) showing strong FC as early as 2 weeks of age, whereas higher-order visual and attentional areas (e.g., MT-AST, LIP-FEF) show weak FC; (2) functional changes were pathway-specific (e.g., robust FC increases detected in the most anterior aspect of the object pathway (TE-AMY), but FC remained weak in the other pathways (e.g., AST-AMY)); (3) FC matures similarly in both right and left hemispheres. Our findings suggest that visual pathways in infant macaques undergo selective remodeling during the first 3 months of life, likely regulated by early social interactions and supporting the transition to independence from the mother.

Social visual engagement in infants and toddlers with autism: early developmental transitions and a model of pathogenesis.

Efforts to determine and understand the causes of autism are currently hampered by a large disconnect between recent molecular genetics findings that are associated with the condition and the core behavioral symptoms that define the condition. In this perspective piece, we propose a systems biology framework to bridge that gap between genes and symptoms. The framework focuses on basic mechanisms of socialization that are highly-conserved in evolution and are early-emerging in development. By conceiving of these basic mechanisms of socialization as quantitative endophenotypes, we hope to connect genes and behavior in autism through integrative studies of neurodevelopmental, behavioral, and epigenetic changes. These changes both lead to and are led by the accomplishment of specific social adaptive tasks in a typical infant's life. However, based on recent research that indicates that infants later diagnosed with autism fail to accomplish at least some of these tasks, we suggest that a narrow developmental period, spanning critical transitions from reflexive, subcortically-controlled visual behavior to interactional, cortically-controlled and social visual behavior be prioritized for future study. Mapping epigenetic, neural, and behavioral changes that both drive and are driven by these early transitions may shed a bright light on the pathogenesis of autism.