Bertone Armando, Mottron Laurent, Jelenic Patricia, Faubert Jocelyn
Visual Psychophysics and Perception Laboratory, Ecole d'optométrie, Université de Montréal, Montréal, Canada.
Brain. 2005 Oct;128(Pt 10):2430-41. doi: 10.1093/brain/awh561. Epub 2005 Jun 15.
Visuo-perceptual processing in autism is characterized by intact or enhanced performance on static spatial tasks and inferior performance on dynamic tasks, suggesting a deficit of dorsal visual stream processing in autism. However, previous findings by Bertone et al. indicate that neuro-integrative mechanisms used to detect complex motion, rather than motion perception per se, may be impaired in autism. We present here the first demonstration of concurrent enhanced and decreased performance in autism on the same visuo-spatial static task, wherein the only factor dichotomizing performance was the neural complexity required to discriminate grating orientation. The ability of persons with autism was found to be superior for identifying the orientation of simple, luminance-defined (or first-order) gratings but inferior for complex, texture-defined (or second-order) gratings. Using a flicker contrast sensitivity task, we demonstrated that this finding is probably not due to abnormal information processing at a sub-cortical level (magnocellular and parvocellular functioning). Together, these findings are interpreted as a clear indication of altered low-level perceptual information processing in autism, and confirm that the deficits and assets observed in autistic visual perception are contingent on the complexity of the neural network required to process a given type of visual stimulus. We suggest that atypical neural connectivity, resulting in enhanced lateral inhibition, may account for both enhanced and decreased low-level information processing in autism.
在静态空间任务中表现正常或增强，而在动态任务中表现较差，这表明自闭症患者的背侧视觉流处理存在缺陷。然而，Bertone等人之前的研究结果表明，自闭症患者用于检测复杂运动的神经整合机制可能受损，而非运动感知本身。我们在此首次证明，自闭症患者在同一视觉空间静态任务中同时表现出增强和降低的能力，其中区分表现的唯一因素是辨别光栅方向所需的神经复杂性。研究发现，自闭症患者识别简单的、亮度定义（或一阶）光栅方向的能力较强，但识别复杂的、纹理定义（或二阶）光栅方向的能力较弱。通过闪烁对比敏感度任务，我们证明这一发现可能并非由于皮层下水平（大细胞和小细胞功能）的异常信息处理所致。综合来看，这些发现被解释为自闭症患者低水平感知信息处理发生改变的明确迹象，并证实自闭症患者视觉感知中观察到的缺陷和优势取决于处理给定类型视觉刺激所需神经网络的复杂性。我们认为，导致侧向抑制增强的非典型神经连接可能是自闭症患者低水平信息处理增强和降低的原因。
