Rivest Jessica B, Jemel Boutheina, Bertone Armando, McKerral Michelle, Mottron Laurent
University of Montreal Center of Excellence for Pervasive Developmental Disorders (CETEDUM), Montreal, Quebec, Canada ; Centre de Recherche en Neuropsychologie et Cognition (CERNEC) and Department of Psychology, University of Montreal, Montreal, Quebec, Canada.
PLoS One. 2013 Oct 24;8(10):e78978. doi: 10.1371/journal.pone.0078978. eCollection 2013.
According to the complexity-specific hypothesis, the efficacy with which individuals with autism spectrum disorder (ASD) process visual information varies according to the extensiveness of the neural network required to process stimuli. Specifically, adults with ASD are less sensitive to texture-defined (or second-order) information, which necessitates the implication of several cortical visual areas. Conversely, the sensitivity to simple, luminance-defined (or first-order) information, which mainly relies on primary visual cortex (V1) activity, has been found to be either superior (static material) or intact (dynamic material) in ASD. It is currently unknown if these autistic perceptual alterations are present in childhood. In the present study, behavioural (threshold) and electrophysiological measures were obtained for static luminance- and texture-defined gratings presented to school-aged children with ASD and compared to those of typically developing children. Our behavioural and electrophysiological (P140) results indicate that luminance processing is likely unremarkable in autistic children. With respect to texture processing, there was no significant threshold difference between groups. However, unlike typical children, autistic children did not show reliable enhancements of brain activity (N230 and P340) in response to texture-defined gratings relative to luminance-defined gratings. This suggests reduced efficiency of neuro-integrative mechanisms operating at a perceptual level in autism. These results are in line with the idea that visual atypicalities mediated by intermediate-scale neural networks emerge before or during the school-age period in autism.
根据复杂性特定假说，自闭症谱系障碍（ASD）个体处理视觉信息的效能会根据处理刺激所需神经网络的广泛程度而有所不同。具体而言，患有ASD的成年人对纹理定义（或二阶）信息的敏感度较低，而处理此类信息需要多个皮层视觉区域的参与。相反，对主要依赖初级视觉皮层（V1）活动的简单的、亮度定义（或一阶）信息的敏感度，在ASD中被发现要么更高（静态材料）要么未受影响（动态材料）。目前尚不清楚这些自闭症感知改变在儿童期是否存在。在本研究中，我们对向患有ASD的学龄儿童呈现的静态亮度和纹理定义光栅进行了行为学（阈值）和电生理学测量，并与发育正常儿童进行了比较。我们的行为学和电生理学（P140）结果表明，自闭症儿童的亮度处理可能并无异常。关于纹理处理，两组之间没有显著的阈值差异。然而，与正常儿童不同，自闭症儿童在面对纹理定义光栅相对于亮度定义光栅时，并未表现出可靠增强的大脑活动（N230和P340）。这表明自闭症患者在感知层面上神经整合机制的效率有所降低。这些结果与以下观点一致，即在自闭症中，由中等规模神经网络介导的视觉异常在学龄期之前或期间就已出现。
