语义知识神经表征的fMRI研究:通道特异性或类别特异性?

fMRI RESEARCH ON THE NEURAL REPRESENTATIONS ABOUT SEMANTIC KNOWLEDGE:MODALITY SPECIFICITY OR CATEGORY SPECIFICITY?

在同一实验中同时考虑类别与通道二个因素,并采用典型的语义提取任务应用功能磁共振成像技术探讨了语义知识的神经基础,结果发现不同类型的语义知识的脑激活模式(含左梭形回的激活)无论在范围还是强度上存在很大的相似性;而且,在严格的统计阈值下,不存在通道或是类别特异性激活的脑区。结果提示语义知识的神经表征分布于整个大脑皮层;在提取物体语义知识时都会同时激活该物体的视觉表象。另外,研究观察到的语义提取过程中BA9区的激活进一步证实并扩展了关于“汉语和表音文字在皮层组织上存在重要差异的观点”。

The study was performed to explore the neural basis about semantics by fMRI, with a better-controlled experimental design which considered both modalities and category in one study and took the typical questions of semantic retrieval as cognitive task. It was found that the pattern of brain activation (including the activation in left fusiform) evoked by different types of semantic information was very similar at its extent and peak value. Moreover, with a strict statistical threshold, no brain areas specifically related to the retrieval of either categorical or modality information was found. Results suggested that human semantic system be undifferentiated by category or modality at the neural level and the activation of visual imagery of a concrete object may go with the retrieval of any of its information. And what’s more, the activation of BA9 observed in this study corroborated and extended the claim that there may be important difference in cortical organization of English and Chinese.