Uddin Lucina Q, Kaplan Jonas T, Molnar-Szakacs Istvan, Zaidel Eran, Iacoboni Marco
Department of Psychology, University of California, Box 951563, B627 Franz Hall, Los Angeles, CA 90095, USA.
Neuroimage. 2005 Apr 15;25(3):926-35. doi: 10.1016/j.neuroimage.2004.12.018.
Self-recognition has been demonstrated by a select number of primate species and is often used as an index of self-awareness. Whether a specialized neural mechanism for self-face recognition in humans exists remains unclear. We used event-related fMRI to investigate brain regions selectively activated by images of one's own face. Ten right-handed normal subjects viewed digital morphs between their own face and a gender-matched familiar other presented in a random sequence. Subjects were instructed to press a button with the right hand if the image looked like their own face, and another button if it looked like a familiar or scrambled face. Contrasting the trials in which images contain more "self" with those containing more familiar "other" revealed signal changes in the right hemisphere (RH) including the inferior parietal lobule, inferior frontal gyrus, and inferior occipital gyrus. The opposite contrast revealed voxels with higher signal intensity for images of "other" than for "self" in the medial prefrontal cortex and precuneus. Additional contrasts against baseline revealed that activity in the "self" minus "other" contrasts represent signal increases compared to baseline (null events) in "self" trials, while activity in the "other" minus "self" contrasts represent deactivations relative to baseline during "self" trials. Thus, a unique network involving frontoparietal structures described as part of the "mirror neuron system" in the RH underlies self-face recognition, while regions comprising the "default/resting state" network deactivate less for familiar others. We provide a model that reconciles these findings and previously published work to account for the modulations in these two networks previously implicated in social cognition.
一些灵长类物种已表现出自我识别能力,且自我识别常被用作自我意识的一个指标。人类是否存在用于自我面部识别的专门神经机制仍不清楚。我们使用事件相关功能磁共振成像(fMRI)来研究被试自己面部图像选择性激活的脑区。十名右利手正常受试者观看了他们自己的面部与一名性别匹配的熟悉他人面部之间的数字变形图像,这些图像以随机顺序呈现。受试者被指示,如果图像看起来像他们自己的脸,就用右手按一个按钮;如果看起来像一张熟悉的脸或打乱的脸,就按另一个按钮。将图像包含更多“自我”特征的试验与包含更多熟悉“他人”特征的试验进行对比,结果显示右半球(RH)包括下顶叶小叶、额下回和枕下回有信号变化。相反的对比显示,在内侧前额叶皮质和楔前叶中,“他人”图像的体素信号强度高于“自我”图像。与基线的额外对比显示,“自我”减去“他人”对比中的活动代表在“自我”试验中相对于基线(空事件)的信号增加,而“他人”减去“自我”对比中的活动代表在“自我”试验期间相对于基线的失活。因此,一个涉及额顶叶结构的独特网络(被描述为RH中“镜像神经元系统”的一部分)是自我面部识别的基础,而构成“默认/静息状态”网络的区域对熟悉他人的失活程度较小。我们提供了一个模型,该模型整合了这些发现和先前发表的研究成果,以解释这两个先前与社会认知相关的网络中的调节作用。