Department Human Perception, Cognition and Action, Max Planck Institute for Biological Cybernetics, Max-Planck-Ring 8, 72076 Tübingen, Germany; Laboratory for Human Systems Neuroscience, RIKEN Brain Science Institute, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan; Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, 43 Vassar Street, Cambridge, MA 02139, USA.
Department Human Perception, Cognition and Action, Max Planck Institute for Biological Cybernetics, Max-Planck-Ring 8, 72076 Tübingen, Germany; Division of Medical Psychology and Department of Psychiatry, University of Bonn, Sigmund Freud Str. 25, 53105 Bonn, Germany.
Neuroimage. 2018 May 15;172:689-702. doi: 10.1016/j.neuroimage.2018.02.013. Epub 2018 Feb 10.
What cortical mechanisms allow humans to easily discern the expression or identity of a face? Subjects detected changes in expression or identity of a stream of dynamic faces while we measured BOLD responses from topographically and functionally defined areas throughout the visual hierarchy. Responses in dorsal areas increased during the expression task, whereas responses in ventral areas increased during the identity task, consistent with previous studies. Similar to ventral areas, early visual areas showed increased activity during the identity task. If visual responses are weighted by perceptual mechanisms according to their magnitude, these increased responses would lead to improved attentional selection of the task-appropriate facial aspect. Alternatively, increased responses could be a signature of a sensitivity enhancement mechanism that improves representations of the attended facial aspect. Consistent with the latter sensitivity enhancement mechanism, attending to expression led to enhanced decoding of exemplars of expression both in early visual and dorsal areas relative to attending identity. Similarly, decoding identity exemplars when attending to identity was improved in dorsal and ventral areas. We conclude that attending to expression or identity of dynamic faces is associated with increased selectivity in representations consistent with sensitivity enhancement.
是什么皮质机制让人类能够轻易辨别出一张脸的表情或身份？在研究人员测量从整个视觉层级中具有拓扑和功能定义的区域得来的大脑血容量反应时，实验对象检测到了一连串动态人脸的表情或身份变化。在表情任务中，背侧区域的反应增加，而在身份任务中，腹侧区域的反应增加，这与之前的研究结果一致。与腹侧区域类似，早期视觉区域在身份任务中表现出活动增加。如果视觉反应根据其幅度被感知机制加权，那么这些增加的反应将导致对任务适当的面部方面的注意力选择得到改善。或者，增加的反应可能是一种敏感性增强机制的特征，该机制可以改善被注意到的面部方面的表示。与后一种敏感性增强机制一致，与注意身份相比，注意表情会导致在早期视觉和背侧区域中对表情范例的解码得到增强。同样，当注意身份时，在背侧和腹侧区域中对身份范例的解码得到改善。我们的结论是，注意动态人脸的表情或身份与增强的敏感性一致，与表示的选择性增加有关。
