Giesbrecht Barry, Camblin C Christine, Swaab Tamara Y
Center for Mind & Brain, University of California, One Shields Avenue, Davis, CA 95616, USA.
Cereb Cortex. 2004 May;14(5):521-9. doi: 10.1093/cercor/bhh014. Epub 2004 Mar 28.
Understanding the neural representation of semantic concepts is at the core of understanding human knowledge and experience. Competing cognitive theories suggest that these neural representations are based on either a unitary semantic code or on multiple semantic codes. We contrasted these theories using event-related fMRI in a semantic priming study. Pairs of words were presented that were either semantically related or unrelated and were either high or low imageable. The unitary view predicts that there should be little or no difference between neural activity evoked by high and low imageable words when presented in a related context, but large differences in neural activity when there is an unrelated context. In contrast to this view, we provide evidence for functionally and anatomically separable effects of context and imageability in human cortex, suggesting that semantic knowledge consists of multiple representational codes.
理解语义概念的神经表征是理解人类知识和经验的核心。相互竞争的认知理论表明，这些神经表征要么基于单一语义代码，要么基于多个语义代码。我们在一项语义启动研究中使用事件相关功能磁共振成像对这些理论进行了对比。呈现的词对要么语义相关，要么语义不相关，且要么具有高可想象性，要么具有低可想象性。单一观点预测，当在相关语境中呈现时，高可想象性和低可想象性的词所引发的神经活动之间应该几乎没有差异，或者没有差异，但在不相关语境中时，神经活动会有很大差异。与这一观点相反，我们提供了证据表明，在人类皮层中，语境和可想象性在功能和解剖学上具有可分离的效应，这表明语义知识由多个表征代码组成。
