239 research outputs found

    Knowledge-driven perceptual organization reshapes information sampling via eye movements

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    Humans constantly move their eyes to explore the environment. However, how image-computable features and object representations contribute to eye-movement control is an ongoing debate. Recent developments in object perception indicate a complex relationship between features and object representations, where image-independent object knowledge generates objecthood by reconfiguring how feature space is carved up. Here, we adopt this emerging perspective, asking whether object-oriented eye movements result from gaze being guided by image-computable features, or by the fact that these features are bound into an object representation. We recorded eye movements in response to stimuli that initially appear as meaningless patches but are experienced as coherent objects once relevant object knowledge has been acquired. We demonstrate that fixations on identical images are more object-centered, less dispersed, and more consistent across observers once these images are organized into objects. Gaze guidance also showed a shift from exploratory information sampling to exploitation of object-related image areas. These effects were evident from the first fixations onwards. Importantly, eye movements were not fully determined by knowledge-dependent object representations but were best explained by the integration of these representations with image-computable features. Overall, the results show how information sampling via eye movements is guided by a dynamic interaction between image-computable features and knowledge-driven perceptual organization

    Repetition suppression and memory for faces is reduced in adults with autism spectrum conditions

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    Autism spectrum conditions (ASC) are associated with a number of atypicalities in face processing, including difficulties in face memory. However, the neural mechanisms underlying this difficulty are unclear. In neurotypical individuals, repeated presentation of the same face is associated with a reduction in activity, known as repetition suppression (RS), in the fusiform face area (FFA). However, to date, no studies have investigated RS to faces in individuals with ASC, or the relationship between RS and face memory. Here, we measured RS to faces and geometric shapes in individuals with a clinical diagnosis of an ASC and in age and IQ matched controls. Relative to controls, the ASC group showed reduced RS to faces in bilateral FFA and reduced performance on a standardized test of face memory. By contrast, RS to shapes in object-selective regions and object memory did not differ between groups. Individual variation in face memory performance was positively correlated with RS in regions of left parietal and prefrontal cortex. These findings suggest difficulties in face memory in ASC may be a consequence of differences in the way faces are stored and/or maintained across a network of regions involved in both visual perception and shortterm/ working memory

    The components of interpersonal synchrony in the typical population and in autism: a conceptual analysis

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    Interpersonal synchrony – the tendency for social partners to temporally co-ordinate their behaviour when interacting – is a ubiquitous feature of social interactions. Synchronous interactions play a key role in development, and promote social bonding and a range of pro-social behavioural outcomes across the lifespan. The process of achieving and maintaining interpersonal synchrony is highly complex, with inputs required from across perceptual, temporal, motor, and socio-cognitive domains. In this conceptual analysis, we synthesise evidence from across these domains to establish the key components underpinning successful non-verbal interpersonal synchrony, how such processes interact, and factors that may moderate their operation. We also consider emerging evidence that interpersonal synchrony is reduced in autistic populations. We use our account of the components contributing to interpersonal synchrony in the typical population to identify potential points of divergence in interpersonal synchrony in autism. The relationship between interpersonal synchrony and broader aspects of social communication in autism are also considered, together with implications for future research

    Intact priors for gaze direction in adults with high-functioning autism spectrum conditions

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    This research was supported by the UK Medical Research Council under project code MC-A060-5PQ50 (Andrew J. Calder). IM was supported by a Leverhulme Trust Project Grant. CC was supported by an Australian Research Council Future Fellowship. SBC was supported by the MRC, the Wellcome Trust and the Autism Research Trust during the period of this work. The research was also supported by the National Institute for Health Research (NIHR) Collaboration for Leadership in Applied Health Research and Care East of England at Cambridgeshire and Peterborough NHS Foundation Trust

    Beyond simultaneity: temporal interdependence of behaviour is key to affiliative effects of interpersonal synchrony in children

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    Interpersonal synchrony (IS) is the temporal co-ordination of behavior during social interactions. IS acts as a social cue signifying affiliation, both when children witness IS between others and when they experience it themselves. However, it is unclear which temporal qualities of IS produce these effects, and why. We hypothesized that the simultaneity and temporal regularity of partners’ actions would each influence affiliation judgements, and that subjective perceptions of IS (‘togetherness’) would play a role in mediating these relations. In two online studies, children aged 4-11 years listened to a pair of children tapping together (witnessed IS; N=68) or themselves tapped with another child (experienced IS; N=63). Tapping partners were presented as real but were virtual. The simultaneity and regularity of their tapping was systematically manipulated across trials. For witnessed IS, both the simultaneity and regularity of partners’ tapping significantly positively affected the perceived degree of affiliation between them. These effects were mediated by the perceived togetherness of the tapping. No affiliative effects of IS were found in the experienced IS condition. Our findings suggest that both the simultaneity and regularity of partners’ actions influence children’s affiliation judgements when witnessing IS, via elicited perceptions of togetherness. We conclude that temporal interdependence – which includes but is not limited to simultaneity of action – is responsible for inducing perceptions of affiliation during witnessed IS

    The effect of perceptual expectation on repetition suppression to faces is not modulated by variation in autistic traits

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    There is substantial variation in the magnitude of the repetition suppression (RS) effects across individuals; however the causes of this variation remain unclear. In a recent study, we found that RS in occipitotemporal cortex was negatively related to individual variation in autistic traits in a neurotypical population. Recent proposals have considered autistic behaviours within a Bayesian framework, suggesting that individuals with autism may have 'attenuated priors' (i.e., their perception is less influenced by prior information). Predictive coding represents a neural instantiation of Bayesian inference, and characterises RS as reduction in prediction error between 'top-down' (prior beliefs) and 'bottom-up' (stimulus related) inputs. In accordance with this, evidence shows that RS is greater when repetition of a stimulus is expected relative to when it is unexpected. Here, using an established paradigm which manipulates the probability of stimulus repetition, we investigated the effect of perceptual expectation on RS in a group of neurotypical individuals varying on a measure of autistic traits. We predicted that the magnitude of the perceptual expectation effect would be negatively related to individual differences in autistic traits. We found a significant effect of perceptual expectation on RS in face-selective regions (i.e., greater RS when repetitions were expected relative to unexpected). However, there was no evidence of a relationship between autistic traits and the magnitude of this effect in any face-selective region of interest (ROI). These findings provide a challenge for the proposal that autism spectrum conditions (ASC) may be associated with the attenuated influence of prior information.This work was supported by the UK Medical Research Council under project codes MC-A060-5PQ50 (Andrew J. Calder) and MC_US_A060_0046 (Richard N. Henson)

    Autism spectrum traits predict the neural response to eye gaze in typical individuals

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    Autism Spectrum Disorders (ASD) are neurodevelopmental disorders characterised by impaired social interaction and communication, restricted interests and repetitive behaviours. The severity of these characteristics are posited to lie on a continuum extending into the typical population, and typical adults' performance on behavioural tasks that are impaired in ASD is correlated with the extent to which they display autistic traits (as measured by Autism Spectrum Quotient, AQ). Individuals with ASD also show structural and functional differences in brain regions involved in social perception. Here we show that variation in AQ in typically developing individuals is associated with altered brain activity in the neural circuit for social attention perception while viewing others' eye gaze. In an fMRI experiment, participants viewed faces looking at variable or constant directions. In control conditions, only the eye region was presented or the heads were shown with eyes closed but oriented at variable or constant directions. The response to faces with variable vs. constant eye gaze direction was associated with AQ scores in a number of regions (posterior superior temporal sulcus, intraparietal sulcus, temporoparietal junction, amygdala, and MT/VS) of the brain network for social attention perception. No such effect was observed for heads with eyes closed or when only the eyes were presented. The results demonstrate a relationship between neurophysiology and autism spectrum traits in the typical (non-ASD) population and suggest that changes in the functioning of the neural circuit for social attention perception is associated with an extended autism spectrum in the typical population. (C) 2011 Elsevier Inc. All rights reserved

    A systematic review of familiarisation methods used in human-robot interactions for autistic participants

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    There is a growing need for standardised familiarisation techniques within the Human-Robot Interaction (HRI) community. This is particularly the case when considering autistic participants, who may have difficulties with the novelty and sensory stimulation associated with meeting a robot. Familiarisation techniques should be considered critical to research, both from an ethical perspective and to achieve research best practice, and are also important in applied settings. In the absence of standardised familiarisation protocols, we conducted a systematic review in accordance with PRISMA guidelines to better understand the range of familiarisation methods used in studies of HRIs with autistic participants. We searched for papers from four different databases: PubMed, Scopus, Web of Science and Science Direct. We identified 387 articles that involved HRIs with autistic participants. The majority did not mention a familiarisation phase (n = 285). A further 52 mentioned including familiarisation but without any description. 50 studies described their familiarisation. Based on a synthesis of these papers, we identified six familiarisation techniques that are commonly used. Using co-production techniques with the autistic community and other participant groups, future studies should validate and critically evaluate the approaches identified in this review. In order to help facilitate improved reporting and critical evaluation of familiarisation approaches across studies we have setup a familiarisation repository

    Obesity-associated melanocortin-4 receptor mutations are associated with changes in the brain response to food cues.

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    CONTEXT: Mutations in the melanocortin-4 receptor (MC4R) represent the commonest genetic form of obesity and are associated with hyperphagia. OBJECTIVE: The aim of this study was to investigate whether melanocortin signaling modulates anticipatory food reward by studying the brain activation response to food cues in individuals with MC4R mutations. Design/Setting/Participants/Main Outcome Measure: We used functional magnetic resonance imaging to measure blood oxygen level-dependent responses to images of highly palatable, appetizing foods, bland foods, and non-food objects in eight obese individuals with MC4R mutations, 10 equally obese controls, and eight lean controls with normal MC4R genotypes. Based on previous evidence, we performed a region-of-interest analysis centered on the caudate/putamen (dorsal striatum) and ventral striatum. RESULTS: Compared to non-foods, appetizing foods were associated with activation in the dorsal and ventral striatum in lean controls and in MC4R-deficient individuals. Surprisingly, we observed reduced activation of the dorsal and ventral striatum in obese controls relative to MC4R-deficient patients and lean controls. There were no group differences for the contrast of disgusting foods with bland foods or non-foods, suggesting that the effects observed in response to appetizing foods were not related to arousal. CONCLUSION: We identified differences in the striatal response to food cues between two groups of obese individuals, those with and those without MC4R mutations. These findings are consistent with a role for central melanocortinergic circuits in the neural response to visual food cues.This is the final published version. It first appeared at http://press.endocrine.org/doi/abs/10.1210/jc.2014-1651
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