Humphreys Kate, Hasson Uri, Avidan Galia, Minshew Nancy, Behrmann Marlene
Carnegie Mellon University, Pittsburgh, Pennsylvania, USA.
Autism Res. 2008 Feb;1(1):52-63. doi: 10.1002/aur.1.
Autism is associated with widespread atypicalities in perception, cognition and social behavior. A crucial question concerns how these atypicalities are reflected in the underlying brain activation. One way to examine possible perturbations of cortical organization in autism is to analyze the activation of category-selective ventral visual cortex, already clearly delineated in typical populations. We mapped out the neural correlates of face, place and common object processing, using functional magnetic resonance imaging (fMRI), in a group of high-functioning adults with autism and a typical comparison group, under both controlled and more naturalistic, viewing conditions. There were no consistent group differences in place-related regions. Although there were no significant differences in the extent of the object-related regions, there was more variability for these regions in the autism group. The most marked group differences were in face-selective cortex, with individuals with autism evincing reduced activation, not only in fusiform face area but also in superior temporal sulcus and occipital face area. Ventral visual cortex appears to be organized differently in high-functioning adults with autism, at least for face-selective regions, although subtle differences may also exist for other categories. We propose that cascading developmental effects of low-level differences in neuronal connectivity result in a much more pronounced effect on later developing cortical systems, such as that for face-processing, than earlier maturing systems (those for objects and places).
自闭症与感知、认知和社会行为方面广泛存在的异常有关。一个关键问题是这些异常如何在潜在的大脑激活中得到体现。研究自闭症中皮质组织可能存在的扰动的一种方法是分析类别选择性腹侧视觉皮层的激活情况，这在典型人群中已得到明确界定。我们使用功能磁共振成像（fMRI），在一组高功能自闭症成年人和一个典型对照组中，在受控和更自然的观看条件下，描绘出了面部、地点和常见物体加工的神经关联。在与地点相关的区域没有一致的组间差异。虽然与物体相关区域的范围没有显著差异，但自闭症组中这些区域的变异性更大。最明显的组间差异出现在面部选择性皮层，自闭症个体不仅在梭状面部区，而且在颞上沟和枕面部区的激活都有所减少。腹侧视觉皮层在高功能自闭症成年人中似乎有不同的组织方式，至少在面部选择性区域是这样，尽管其他类别可能也存在细微差异。我们提出，神经元连接的低水平差异的级联发育效应，对后期发育的皮质系统（如面部加工系统）的影响比对早期成熟系统（物体和地点加工系统）的影响更为显著。
