Department of Neurology, First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China.
PLoS One. 2011;6(8):e23997. doi: 10.1371/journal.pone.0023997. Epub 2011 Aug 26.
It remains controversial and hotly debated whether foveal information is double-projected to both hemispheres or split at the midline between the two hemispheres. We investigated this issue in a unique patient with lesions in the splenium of the corpus callosum and the left medial occipitotemporal region, through a series of neuropsychological tests and multimodal MRI scans. Behavioral experiments showed that (1) the patient had difficulties in reading simple and compound Chinese characters when they were presented in the foveal but left to the fixation, (2) he failed to recognize the left component of compound characters when the compound characters were presented in the central foveal field, (3) his judgments of the gender of centrally presented chimeric faces were exclusively based on the left half-face and he was unaware that the faces were chimeric. Functional MRI data showed that Chinese characters, only when presented in the right foveal field but not in the left foveal field, activated a region in the left occipitotemporal sulcus in the mid-fusiform, which is recognized as visual word form area. Together with existing evidence in the literature, results of the current study suggest that the representation of foveal stimuli is functionally split at object processing levels.
注视点信息是双侧投射到两个半球，还是在两个半球之间的中线处分裂，这仍然存在争议，并引发了激烈的争论。我们通过一系列神经心理学测试和多模态 MRI 扫描，在一位胼胝体压部和左侧内侧枕颞叶区域病变的独特患者中研究了这个问题。行为实验表明：（1）当注视点左侧呈现简单和复合汉字时，患者阅读汉字有困难；（2）当复合汉字呈现于中央注视点时，他无法识别复合汉字的左侧部分；（3）他对中央呈现的嵌合面孔的性别判断仅基于左半张脸，而他并不知道这些面孔是嵌合的。功能磁共振成像数据显示，只有当汉字呈现于右注视点而不是左注视点时，在中梭状回的左侧枕颞叶沟才会激活被认为是视觉单词形式区的区域。结合文献中的现有证据，本研究的结果表明，注视点刺激的表示在物体处理水平上是功能上分裂的。
