Department of Psychology, University of Pennsylvania, Philadelphia, PA 19104-6241, USA.
Neuroimage. 2010 Apr 1;50(2):753-63. doi: 10.1016/j.neuroimage.2009.12.036. Epub 2009 Dec 23.
Sensorimotor-based theories of semantic memory contend that semantic information about an object is represented in the neural substrate invoked when we perceive or interact with it. We used fMRI adaptation to test this prediction, measuring brain activation as participants read pairs of words. Pairs shared function (flashlight-lantern), shape (marble-grape), both (pencil-pen), were unrelated (saucer-needle), or were identical (drill-drill). We observed adaptation for pairs with both function and shape similarity in left premotor cortex. Further, degree of function similarity was correlated with adaptation in three regions: two in the left temporal lobe (left medial temporal lobe, left middle temporal gyrus), which has been hypothesized to play a role in mutimodal integration, and one in left superior frontal gyrus. We also found that degree of manipulation (i.e., action) and function similarity were both correlated with adaptation in two regions: left premotor cortex and left intraparietal sulcus (involved in guiding actions). Additional considerations suggest that the adaptation in these two regions was driven by manipulation similarity alone; thus, these results imply that manipulation information about objects is encoded in brain regions involved in performing or guiding actions. Unexpectedly, these same two regions showed increased activation (rather than adaptation) for objects similar in shape. Overall, we found evidence (in the form of adaptation) that objects that share semantic features have overlapping representations. Further, the particular regions of overlap provide support for the existence of both sensorimotor and amodal/multimodal representations.
基于感觉运动的语义记忆理论认为，当我们感知或与物体互动时，关于物体的语义信息会在被调用的神经基质中得到表示。我们使用 fMRI 适应来测试这一预测，测量参与者阅读单词对时的大脑激活情况。单词对共享功能（手电筒-灯笼）、形状（大理石-葡萄）、两者兼具（铅笔-钢笔）、不相关（碟子-针）或相同（钻头-钻头）。我们观察到在左前运动皮层中，具有功能和形状相似性的单词对存在适应现象。此外，功能相似程度与三个区域的适应程度相关：两个在左颞叶（左内侧颞叶、左颞中回），这些区域被假设在多模态整合中发挥作用，另一个在左额上回。我们还发现，操作程度（即动作）和功能相似性都与两个区域的适应相关：左前运动皮层和左顶内沟（参与指导动作）。进一步的考虑表明，这两个区域的适应仅由操作相似性驱动；因此，这些结果意味着物体的操作信息被编码在执行或指导动作的大脑区域中。出乎意料的是，这两个区域对形状相似的物体显示出增加的激活（而不是适应）。总的来说，我们发现了证据（以适应的形式），即具有共享语义特征的物体具有重叠的表示。此外，重叠的特定区域为感觉运动和非模态/多模态表示的存在提供了支持。
