Zion-Golumbic Elana, Golan Tal, Anaki David, Bentin Shlomo
Department of Cognitive Sciences, Hebrew University of Jerusalem, Jerusalem, Israel.
Neuroimage. 2008 Feb 15;39(4):1980-7. doi: 10.1016/j.neuroimage.2007.10.025. Epub 2007 Nov 7.
Previous studies demonstrated that induced EEG activity in the gamma band (iGBA) plays an important role in object recognition and is modulated by stimulus familiarity and its compatibility with pre-existent representations. In the present study we investigated the modulation of iGBA by the degree of familiarity and perceptual expertise that observers have with stimuli from different categories. Specifically, we compared iGBA in response to human faces versus stimuli which subjects are not expert with (ape faces, human hands, buildings and watches). iGBA elicited by human faces was higher and peaked earlier than that elicited by all other categories, which did not differ significantly from each other. These findings can be accounted for by two characteristics of perceptual expertise. One is the activation of a richer, stronger and, therefore, more easily accessible mental representation of human faces. The second is the more detailed perceptual processing necessary for within-category distinctions, which is the hallmark of perceptual expertise. In addition, the sensitivity of iGBA to human but not ape faces was contrasted with the face-sensitive N170-effect, which was similar for human and ape faces. In concert with previous studies, this dissociation suggests a multi-level neuronal model of face recognition, manifested by these two electrophysiological measures, discussed in this paper.
先前的研究表明，诱发的伽马波段脑电活动（iGBA）在物体识别中起着重要作用，并受到刺激熟悉度及其与先前存在表征的兼容性的调节。在本研究中，我们调查了观察者对不同类别刺激的熟悉程度和感知专业知识对iGBA的调节作用。具体而言，我们比较了对人脸与受试者不熟悉的刺激（猿脸、人手、建筑物和手表）的iGBA。人脸诱发的iGBA高于所有其他类别诱发的iGBA，且峰值出现得更早，而其他类别之间没有显著差异。这些发现可以由感知专业知识的两个特征来解释。一个是激活了更丰富、更强且因此更容易获取的人脸心理表征。另一个是类别内区分所需的更详细的感知处理，这是感知专业知识的标志。此外，iGBA对人脸而非猿脸的敏感性与对面敏感的N170效应形成对比，后者对人脸和猿脸相似。与先前的研究一致，这种分离表明了一种人脸识别的多层次神经元模型，由本文讨论的这两种电生理测量表现出来。
