Dr Giorgia Bussu Hi, my name is Giorgia Bussu. I’m a Neuroscientist, and I work as a Biostatistician at Sence Research AB in Uppsala, Sweden, and I’m here to talk about a study that I’ve conducted together with my colleagues at Uppsala University, where we studied sensory processing. So, we know that people vary significantly in how they experience the world through their senses, and that is what we define more broadly in neuroscience as “sensory processing,” and its variability is evident in young babies already, and the way they respond to external stimuli has relevant implications for their development across the whole neurodevelopmental spectrum. So, what is relevant to the conception of our study is that this variability may have a strong genetic basis, but we know very little about which etiological factors influence sensory differences in infancy. And that is a very crucial time, because that’s when brain circuits supporting both social and non-social cognition are sculptured, and then babies learn a lot about the world via sensory input, especially in re – in interaction with the caregivers. So, we wanted to understand how variability among babies in these sensory-related behaviours maps out in terms of the structure of these differences in the observation of those behaviour in everyday life as reported by parents. And then we wanted to see which factors influence this variability, whether it’s genetics or the environments, and whether it’s shared across different behaviours or not. And, most of all, we wanted to try and see what was the link between this variability very early in age and then neurodevelopment when it comes to autism in particular. So, when I talk about different domains of sensory processing, I mean the different senses, so the vision, hearing, vortex tests in relation, for example. But when I talk about “dimensions,” I talk about what – the so called “quadrants.” So, previous research has shown that the way we respond to signal from our senses, the behaviours that we observe in relation to that, may separate across different dimensions. And we define that as “sensory sensitivity,” so in the case of babies, for example, a baby who jumps at loud noises, “sensation seeking,” that may be a baby who likes to look at spinning objects or toys, “sensation avoiding,” that may be a baby who is, for example, resistant to cuddles, and then “low registration” or “under-responsivity,” and that may be a baby who instead doesn’t seem to react to loud noises. So, we wanted to see how this variability in these behaviours maps out in babies, whether it maps out to these quadrants, because we know that there is renewed interest in sensory processing, a lot of research is focusing on that now. And there are contrasting findings when it comes to these quadrants, so we wanted to see whether the structure holds in infancy, before moving on to try and understand what are the influences, whether it’s genetics or environment, and so on. So, we tackled this issue by investigating these factors in very young babies, in particular, 300 baby twins around five months of age, and they participated in the BabyTwins Study, Sweden, and then we used a standardised instrument to measure the children’s response to sensory stimuli, that is the Infant/Toddler Sensory Profile. And then we used statistical methods to try and address our research questions, in particular, the exploratory factor analysis for the phenotypic structure of sensory variability, the multivariate twin models for the etiological influences, and then generalised estimating equations to try and link this variability in sensory behaviours to later autistic traits, around three years of age. And then our results showed actually that the structure holds, so there is separability of how the baby – the babies differ in sensory-related behaviours across different dimensions of sensory processing and the quadrants that I talked about before, and so, we could actually map out this – the behaviours across these different four dimensions. And by investigating the influences we provided additional support to the separability when it comes to the genetic – unique genetic contribution to variability across different dimensions. Then there was the strongest influences that come – came from shared environment, and that was instead more shared across different domains. So, we want to highlight this structure of four different quadrants in variability in sensory processing, and how this variability is uniquely influenced by genetic and environmental influences. And that is what’s most likely contribute to the rich spectrum of sensory-related behaviour that we observe in babies and people more generally. So, we found in particular a high heritability for sensory sensitivity, around 44%, and for tactile behaviours, around 38%, but most of the influence, the strongest influence, came from shared environment. And that we interpret, for example, as family environment, the interaction with the caregivers and how the babies respond different to the world in relation to that. So, young infants may be more passive when it comes to the environmental exposure to the sensory stimuli, and so we interpret the influences from shared environment when it comes to the exposure mediated by the caregivers and the parents. So they may be the ones more in charge when it comes to sensory stimuli and playing a relevant role than compared to what may be more of a baby specific choices that may have a stronger influence later in development. And then we found unique associations with the level of autistic traits in toddlerhood, in particular for sensory sensitivity, but also under-responsivity and sensation avoiding. So, we give a new perspective with the study on the developmental cascade process that results in the highly variable manifestation of autism when it comes especially to sensory-related behaviours. So, we speculate that the variability across the spectrum of behavioural and symptom manifestation in autism is a result of the interaction across these different strains that underly different dimensions of sensory processing in everyday life, and then environmental influences that scaffold the early sensory experiences, that may have separate and unique influences across these four sensory dimension, and then result in a very, very much higher level of variability. And then the early caregiving environment is likely to mediate this cascading effect of the alterations that we observe in sensory processing in infancy. And we have, sort of, support through the parent-mediated interventions that are conducted on younger siblings of autistic children. So, different aspects of parent responsiveness, for example, or directiveness and scaffolding may influence a child’s sensory experience differently, in everyday settings, and then in turn influence how these children learn from the world. So, future work should actually follow-up on these findings in clinical samples, and see how this dynamic interplay between the infant and caregiver may actually influence more specific aspects of sensory processing in – and then in turn development of autism. So, the – our results have implications for the development of support strategies and interventions that’s conducted in a – in autism, for example, that target sensory experience and sensory-related behaviours. So we suggest that, for example, these strategies may benefit from more narrow targeting of each sensory domain and dimension.