State Key Laboratory of Cognitive Neuroscience and Learning & IDG/McGovern Institute for Brain Research, Beijing Normal University, Beijing, 100875, China.
Center for Mind/Brain Sciences (CIMeC), University of Trento, Trento, 38123, Italy; International School for Advanced Studies (SISSA), Trieste, 34136, Italy.
Neuroimage. 2020 Jul 15;215:116838. doi: 10.1016/j.neuroimage.2020.116838. Epub 2020 Apr 13.
The human ventral visual cortex is functionally organized into different domains that sensitively respond to different categories, such as words and objects. There is heated debate over what principle constrains the locations of those domains. Taking the visual word form area (VWFA) as an example, we tested whether the word preference in this area originates from the bottom-up processes related to word shape (the shape hypothesis) or top-down connectivity of higher-order language regions (the connectivity hypothesis). We trained subjects to associate identical, meaningless, non-word-like figures with high-level features of either words or objects. We found that the word-feature learning for the figures elicited the neural activation change in the VWFA, and learning performance effectively predicted the activation strength of this area after learning. Word-learning effects were also observed in other language areas (i.e., the left posterior superior temporal gyrus, postcentral gyrus, and supplementary motor area), with increased functional connectivity between the VWFA and the language regions. In contrast, object-feature learning was not associated with obvious activation changes in the language regions. These results indicate that high-level language features of stimuli can modulate the activation of the VWFA, providing supportive evidence for the connectivity hypothesis of words processing in the ventral occipitotemporal cortex.
人类腹侧视觉皮层在功能上组织成不同的区域，这些区域对不同的类别（如单词和物体）敏感。对于什么原则约束这些区域的位置，存在激烈的争论。以视觉词形区（VWFA）为例，我们测试了该区域中的单词偏好是否源自与单词形状相关的自下而上的过程（形状假说），还是来自于高级语言区域的自上而下的连通性（连接假说）。我们训练受试者将相同的、无意义的、非单词样的图形与单词或物体的高级特征联系起来。我们发现，图形的单词特征学习引起了 VWFA 中的神经激活变化，并且学习后的学习表现可以有效地预测该区域的激活强度。在其他语言区域（即左侧后上颞叶回、中央后回和补充运动区）也观察到了单词学习效应，VWFA 与语言区域之间的功能连接增强。相比之下，物体特征学习与语言区域中的明显激活变化无关。这些结果表明，刺激的高级语言特征可以调节 VWFA 的激活，为腹侧枕颞叶皮层中单词处理的连接假说提供了支持性证据。
