School of Psychology, UNSW Sydney, NSW, Australia.
Institute of Cognitive Neuroscience, UCL, London, UK; Wellcome Trust Centre for Neuroscience, UCL, London, UK; Department of Psychology, University of Cambridge, Cambridge, UK.
Cortex. 2018 Jun;103:13-23. doi: 10.1016/j.cortex.2018.02.005. Epub 2018 Feb 21.
Progress in our understanding of autism spectrum disorder (ASD) has recently been sought by characterising how systematic differences in canonical neural computations employed across the sensory cortex might contribute to clinical symptoms in diverse sensory, cognitive, and social domains. A key proposal is that ASD is characterised by reduced divisive normalisation of sensory responses. This provides a bridge between genetic and molecular evidence for an increased ratio of cortical excitation to inhibition in ASD and the functional characteristics of sensory coding that are relevant for understanding perception and behaviour. Here we tested this hypothesis in the context of gaze processing (i.e., the perception of other people's direction of gaze), a domain with direct relevance to the core diagnostic features of ASD. We show that reduced divisive normalisation in gaze processing is associated with specific predictions regarding the psychophysical effects of sensory adaptation to gaze direction, and test these predictions in adults with ASD. We report compelling evidence that both divisive normalisation and sensory adaptation occur robustly in adults with ASD in the context of gaze processing. These results have important theoretical implications for defining the types of divisive computations that are likely to be intact or compromised in this condition (e.g., relating to local vs distal control of cortical gain). These results are also a strong testament to the typical sensory coding of gaze direction in ASD, despite the atypical responses to others' gaze that are a hallmark feature of this diagnosis.
自闭症谱系障碍(ASD)的研究进展最近通过描述整个感觉皮层中规范的神经计算的系统差异如何有助于各种感觉、认知和社会领域的临床症状来寻求。一个关键的假设是,ASD 的特征是感觉反应的有区别的正常化减少。这为 ASD 中皮质兴奋与抑制的比率增加的遗传和分子证据以及与理解感知和行为相关的感觉编码的功能特征之间提供了桥梁。在这里,我们在注视处理(即感知他人的注视方向)的背景下检验了这一假设,注视处理是与 ASD 的核心诊断特征直接相关的领域。我们表明,注视处理中减少的有区别的正常化与关于对注视方向的感觉适应的心理物理学效应的特定预测相关,并在 ASD 成人中测试了这些预测。我们报告了令人信服的证据,表明在注视处理中,ASD 成人的有区别的正常化和感觉适应都很强烈。这些结果对定义在这种情况下可能完整或受损的有区别的计算类型具有重要的理论意义(例如,与皮质增益的局部与远程控制有关)。这些结果也是 ASD 中注视方向的典型感觉编码的有力证明,尽管对他人注视的反应异常是该诊断的一个显著特征。