Teodora Gliga

Sleep difficulties (e.g., increased sleep onset latency and more frequent night awakenings) are common in early development and are associated with increased parental stress. Sleep difficulties have been linked to sensory hypersensitivity in typically developing infants and infants with family history of autism. In the current study, we investigate whether infant sensory sensitivity is associated with the strategies parents employ when settling infants to sleep. Strategies encouraging autonomy, rather than those involving active physical comforting, have previously been shown to lead to better sleep. We report findings from a cross‐sectional UK sample of 245 infants aged 6–13 months, from which we collected online parent‐report measures of infant sleep and sensory sensitivity (ITSP). We replicate previous findings showing that poorer sleep is correlated with higher infant sensory sensitivity. We then show an association between higher infant sensory sensitivity and more frequent use of all settling strategies, as well as a higher number of different strategies used. A strong correlation between infant and maternal sensory sensitivity precluded testing whether parental settling strategies are driven by infant or parental sensory sensitivity. The current findings emphasize the need to integrate information about intrinsic (e.g., infant sensitivity) and social environment factors (e.g., parental sensitivity, settling strategies) to understand infant sleep.

Initiating and maintaining sleep requires gating of sensory input. Sensory processing differences, such as elevated sensory reactivity, have emerged as a potential driver of sleep difficulties in autism. Both sensory and sleep difficulties are prevalent in autistic individuals and emerge early in development. Here, we use polysomnography to understand how infant sensory reactivity affects the ability to maintain sleep in a quiet or noisy environment. Forty-four 8- to 11-month-old infants at typical and elevated likelihood for autism participated in a lab-based nap study consisting of two counterbalanced visits, a baseline and an auditory stimulation condition. In the stimulation condition, 60 dB pure tones were played during sleep. We measured slow waves and sleep spindles, electroencephalogram features previously linked to the ability to protect sleep from sensory disturbance. We show that higher caregiver-reported sensory reactivity was significantly associated with lower slow wave activity and density, across both nap conditions. In the stimulation condition, infants with elevated sensory reactivity had even further decreased slow wave density and lower sleep spindle density. Comparisons of pre- and poststimulus windows showed that, rather than triggering immediate event-related disruptions, auditory input and sensory reactivity alter sleep microstructure across the longer timescale of the entire nap. Thus, highly reactive infants experience disruptions in their ability to enter or maintain periods of sensory disconnection, accentuated by the presence of auditory noise.

1. Recognising objects is a vital skill on which humans heavily rely to respond quickly and adaptively to their environment. Yet, we lack understanding on the role visual information sampling plays in this process, and its relation to the individual’s priors. To bridge this gap, the eye-movements of 18 adult participants were recorded during a free-viewing object-recognition task using Dots stimuli (Moca et al., 2011). Participants viewed the stimuli in one of three orders: from most visible to least ( Descending ), least visible to most ( Ascending ) or in a randomised order ( Random ). This dictated the strength of their priors along the experiment. Adding to Moca et al.’s original finding that visibility order influenced participants’ recognition performance and visual exploration, we found that while orders allowing for stronger priors generally led participants to visually sample more informative locations, this was not the case of Random participants. Indeed, they appeared to behave naïvely, and their use of specific object-related priors seemed fully impaired, while they seemed to maintain the ability to use general task-related priors to guide their exploration. These findings have important implications for our understanding of perception, which appears markedly subjective even at the basic level of visual sampling and object perception.

Background: How often a child naps, during infancy, is believed to reflect both intrinsic factors, that is, the need of an immature brain to consolidate information soon after it is acquired, and environmental factors. Difficulty accounting for important environmental factors that interfere with a child's sleep needs (e.g., attending daycare) has clouded our ability to understand the role of intrinsic drivers of napping frequency.Methods: Here we investigate sleep patterns in association with two measures of cognitive ability, vocabulary size, measured with the Oxford‐Communicative Development Inventory (N = 298) and cognitive executive functions (EF), measured with the Early EF Questionnaire (N = 463), in a cohort of 8–38‐month‐olds. Importantly, because of the social distancing measures imposed during the Covid‐19 Spring 2020 lockdown, in the UK, measures of sleep were taken when children did not access daycare settings.Results: We find that children with more frequent but shorter naps than expected for their age had lower concurrent receptive vocabularies, lower cognitive EF and a slower increase in expressive vocabulary from spring to winter 2020, when age, sex, and SES were accounted for. The negative association between vocabulary and frequency of naps became stronger with age.Conclusions: These findings suggest that the structure of daytime sleep is an indicator of cognitive development and highlight the importance of considering environmental perturbations and age when investigating developmental correlates of sleep.

Dimensional approaches to psychopathology interrogate the core neurocognitive domains interacting at the individual level to shape diagnostic symptoms. Embedding this approach in prospective longitudinal studies could transform our understanding of the mechanisms underlying neurodevelopmental disorders. Such designs require us to move beyond traditional group comparisons and determine which domain-specific alterations apply at the level of the individual, and whether they vary across distinct phenotypic subgroups. As a proof of principle, this study examines how the domain of face processing contributes to the emergence of autism spectrum disorder (ASD). We used an event-related potentials (ERPs) task in a cohort of 8-month-old infants with (n = 148) and without (n = 68) an older sibling with ASD, and combined traditional case-control comparisons with machine-learning techniques for prediction of social traits and ASD diagnosis at 36 months, and Bayesian hierarchical clustering for stratification into subgroups. A broad profile of alterations in the time-course of neural processing of faces in infancy was predictive of later ASD, with a strong convergence in ERP features predicting social traits and diagnosis. We identified two main subgroups in ASD, defined by distinct patterns of neural responses to faces, which differed on later sensory sensitivity. Taken together, our findings suggest that individual differences between infants contribute to the diffuse pattern of alterations predictive of ASD in the first year of life. Moving from group-level comparisons to pattern recognition and stratification can help to understand and reduce heterogeneity in clinical cohorts, and improve our understanding of the mechanisms that lead to later neurodevelopmental outcomes.

Background: Although autism spectrum disorder (ASD) is heritable, the mechanisms through which genes contribute to symptom emergence remain unclear. Investigating candidate intermediate phenotypes such as the pupillary light reflex (PLR) prospectively from early in development could bridge genotype and behavioural phenotype. Methods: Using eye tracking, we longitudinally measured the PLR at 9, 14 and 24 months in a sample of infants ( N = 264) enriched for a family history of ASD; 27 infants received an ASD diagnosis at 3 years. We examined the 9‐ to 24‐month developmental trajectories of PLR constriction latency (onset; ms) and amplitude (%) and explored their relation to categorical 3‐year ASD outcome, polygenic liability for ASD and dimensional 3‐year social affect (SA) and repetitive/restrictive behaviour (RRB) traits. Polygenic scores for ASD (PGS _ASD ) were calculated for 190 infants. Results: While infants showed a decrease in latency between 9 and 14 months, higher PGS _ASD was associated with a smaller decrease in latency in the first year (β = −.16, 95% CI = −0.31, −0.002); infants with later ASD showed a significantly steeper decrease in latency (a putative ‘catch‐up’) between 14 and 24 months relative to those with other outcomes (typical: β = .54, 95% CI = 0.08, 0.99; other: β = .53, 95% CI = 0.02, 1.04). Latency development did not associate with later dimensional variation in ASD‐related traits. In contrast, change in amplitude was not related to categorical ASD or genetics, but decreasing 9‐ to 14‐month amplitude was associated with higher SA (β = .08, 95% CI = 0.01, 0.14) and RRB (β = .05, 95% CI = 0.004, 0.11) traits. Conclusions: These findings corroborate PLR development as possible intermediate phenotypes being linked to both genetic liability and phenotypic outcomes. Future work should incorporate alternative measures (e.g. functionally informed structural and genetic measures) to test whether distinct neural mechanisms underpin PLR alterations.

Previous research has provided rich evidence that a set of visual objects can be encoded in isolation along with their exact coordinate positions as well a

It was suggested that children's referent selection may not lay memory traces sufficiently strong to lead to retention of new word-object mappings. If this was the case we expect incorrect selections to be easily rectified through feedback. Previous work suggested this to be the case in toddlers at typical likelihood (TL) but not in those at elevated likelihood (EL) for autism spectrum disorder (ASD) (Bedford et al., 2013). Yet group differences in lexical knowledge may have confounded these findings. Here, TL (N = 29) and EL toddlers (N = 75) chose one of two unfamiliar objects as a referent for a new word. Both groups retained the word-referent mapping above chance when their choices were immediately reinforced but were at chance after corrective feedback. The same pattern of results was obtained when children observed another experimenter make the initial referent choice. Thus, children's referent choices lay memory traces that compete with subsequent correction; these strong word-object associations are not a result of children actively choosing potential referents for new words.

To what extent does language shape how we think about the world? Studies suggest that linguistic symbols expressing conceptual categories (‘apple’, ‘squirrel’) make us focus on categorical information (e.g. that you saw a squirrel) and disregard individual information (e.g. whether that squirrel had a long or short tail). Across two experiments with preverbal infants, we demonstrated that it is not language but nonverbal category knowledge that determines what information is packed into object representations. Twelve-month-olds (N= 48) participated in an electroencephalography (EEG) change-detection task involving objects undergoing a brief occlusion. When viewing objects from unfamiliar categories, infants detected both across- and within-category changes, as evidenced by their negative central wave (Nc) event-related potential. Conversely, when viewing objects from familiar categories, they did not respond to within-category changes, which indicates that nonverbal category knowledge interfered with the representation of individual surface features necessary to detect such changes. Furthermore, distinct patterns of γ and α oscillations between familiar and unfamiliar categories were evident before and during occlusion, suggesting that categorization had an influence on the format of recruited object representations. Thus, we show that nonverbal category knowledge has rapid and enduring effects on object representation and discuss their functional significance for generic knowledge acquisition in the absence of language.

A discrepancy between what was predicted and what is observed has been linked to increased looking times, changes in brain electrical activity, and increased pupil dilation in infants. These processes associated with heightened attention and readiness to learn might enhance the encoding and memory consolidation of the surprising object, as suggested by both the infant and the adult literature. We therefore investigated whether the presence of surprise during the encoding context enhances subsequent encoding and recognition memory processes for the items that violated infants' expectations. Seventeen‐month‐olds viewed 20 familiar objects, half of which were labeled correctly, while the other half were mislabeled. Subsequently, infants were presented with a silent recognition memory test where the previously labeled objects appeared along with new images. Pupil dilation was measured, with more dilated pupils indicating (1) surprise during those labeling events where the item was mislabeled and (2) successful retrieval processes during the memory test. Infants responded with more pupil dilation to mislabeling compared to correct labeling. Importantly, despite the presence of a surprise response during mislabeling, infants only differentiated between the previously seen and unseen items at the memory test, offering no evidence that surprise had facilitated the encoding of the mislabeled items.