Kraut Michael A, Kremen Sarah, Moo Lauren R, Segal Jessica B, Calhoun Vincent, Hart John
Division of Neuroradiology, Johns Hopkins Hospital, Johns Hopkins University, Baltimore, MD 21287, USA.
J Cogn Neurosci. 2002 Jan 1;14(1):37-47. doi: 10.1162/089892902317205302.
The human brain's representation of objects has been proposed to exist as a network of coactivated neural regions present in multiple cognitive systems. However, it is not known if there is a region specific to the process of activating an integrated object representation in semantic memory from multimodal feature stimuli (e.g., picture-word). A previous study using word-word feature pairs as stimulus input showed that the left thalamus is integrally involved in object activation (Kraut, Kremen, Segal, et al., this issue). In the present study, participants were presented picture-word pairs that are features of objects, with the task being to decide if together they "activated" an object not explicitly presented (e.g., picture of a candle and the word "icing" activate the internal representation of a "cake"). For picture-word pairs that combine to elicit an object, signal change was detected in the ventral temporo-occipital regions, pre-SMA, left primary somatomotor cortex, both caudate nuclei, and the dorsal thalami bilaterally. These findings suggest that the left thalamus is engaged for either picture or word stimuli, but the right thalamus appears to be involved when picture stimuli are also presented with words in semantic object activation tasks. The somatomotor signal changes are likely secondary to activation of the semantic object representations from multimodal visual stimuli.
有人提出，人类大脑中物体的表征是以多个认知系统中共同激活的神经区域网络的形式存在。然而，目前尚不清楚是否存在一个特定区域，专门用于从多模态特征刺激（如图像-单词）激活语义记忆中的综合物体表征这一过程。之前一项使用单词-单词特征对作为刺激输入的研究表明，左丘脑整体参与物体激活（克劳特、克雷门、西格尔等人，本期）。在本研究中，向参与者呈现物体特征的图像-单词对，任务是判断它们是否共同“激活”了一个未明确呈现的物体（例如，蜡烛的图片和单词“糖霜”激活了“蛋糕”的内部表征）。对于组合后能引出一个物体的图像-单词对，在腹侧颞枕区、前辅助运动区、左初级躯体运动皮层、双侧尾状核以及双侧背侧丘脑检测到了信号变化。这些发现表明，左丘脑参与处理图像或单词刺激，但在语义物体激活任务中，当图像刺激与单词同时呈现时右丘脑似乎也会参与。躯体运动信号变化可能继发于多模态视觉刺激对语义物体表征的激活。
