Department of Psychology, National Taiwan University, Taipei, Taiwan.
Cortex. 2010 Feb;46(2):217-30. doi: 10.1016/j.cortex.2009.04.003. Epub 2009 Apr 17.
Reading is one of the best well-practiced visual tasks for modern people. We investigated how the visual cortex analyzes spatial configuration in written words by studying the inversion effect in Chinese character processing. We measured the psychometric functions and brain activations for upright real-characters and non-characters and their inverted (upside down) versions. In the psychophysical experiment, the real-characters showed an inversion effect at both 1 degrees and 4 degrees eccentricities, while the non-characters showed no inversion effect for all eccentricities tested. In the functional magnetic resonance image (fMRI) experiment, the left fusiform gyrus and a small area in the bilateral lateral occipital regions showed a significant differential activation between upright and inverted real-characters. The bilateral fusiform gyri also show differential activation between upright real- and non-characters. The dorsal lateral occipital regions showed character-selective activation when compared with scrambled lines. The result suggested that the occipitoparietal regions may analyze the local features of an object regardless of its familiarity. Therefore, the lateral occipital regions may play an intermediate role in integrating the local information in an object. Finally, the fusiform gyrus plays a critical role in analyzing global configurations of a visual word form. This is consistent with the notion that the human visual cortex analyzes an object in a hierarchical way.
阅读是现代人最常进行的视觉活动之一。我们通过研究汉字处理中的反转效应，来研究视觉皮层如何分析书面文字的空间结构。我们测量了直立正字和非正字及其倒置（上下颠倒）版本的心理物理函数和大脑激活。在心理物理学实验中，正字在 1 度和 4 度偏心率下均表现出反转效应，而非正字在所有测试的偏心率下均未表现出反转效应。在功能磁共振成像（fMRI）实验中，左侧梭状回和双侧外侧枕叶的一个小区域在直立和倒置正字之间表现出显著的差异激活。双侧梭状回在直立正字和非正字之间也表现出差异激活。与随机线相比，背外侧枕叶区域表现出字符选择性激活。结果表明，枕顶区可能会分析物体的局部特征，而不考虑其熟悉程度。因此，外侧枕叶区域可能在整合物体的局部信息方面发挥中间作用。最后，梭状回在分析视觉单词的全局结构方面起着关键作用。这与人类视觉皮层以分层方式分析物体的观点一致。
