Matsuyoshi Daisuke, Morita Tomoyo, Kochiyama Takanori, Tanabe Hiroki C, Sadato Norihiro, Kakigi Ryusuke
Department of Integrative Physiology, National Institute for Physiological Sciences, Aichi 444-8585, Japan, Department of Psychology, Graduate School of Human Sciences, Osaka University, Osaka 565-0871, Japan, Research Center for Advanced Science and Technology, University of Tokyo, Tokyo 153-8904, Japan,
Department of Integrative Physiology, National Institute for Physiological Sciences, Aichi 444-8585, Japan, Department of Adaptive Machine Systems, Graduate School of Engineering, Osaka University, Osaka 565-0871, Japan.
J Neurosci. 2015 Mar 11;35(10):4268-79. doi: 10.1523/JNEUROSCI.3960-14.2015.
Humans' ability to recognize objects is remarkably robust across a variety of views unless faces are presented upside-down. Whether this face inversion effect (FIE) results from qualitative (distinct mechanisms) or quantitative processing differences (a matter of degree within common mechanisms) between upright and inverted faces has been intensely debated. Studies have focused on preferential responses to faces in face-specific brain areas, although face recognition also involves nonpreferential responses in non-face-specific brain areas. By using dynamic causal modeling with Bayesian model selection, here we show that dissociable cortical pathways are responsible for qualitative and quantitative mechanisms in the FIE in the distributed network for face recognition. When faces were upright, the early visual cortex (VC) and occipital and fusiform face areas (OFA, FFA) suppressed couplings to the lateral occipital cortex (LO), a primary locus of object processing. In contrast, they did not inhibit the LO when faces were inverted but increased couplings to the intraparietal sulcus, which has been associated with visual working memory. Furthermore, we found that upright and inverted face processing together involved the face network consisting of the VC, OFA, FFA, and inferior frontal gyrus. Specifically, modulatory connectivity within the common pathways (VC-OFA), implicated in the parts-based processing of faces, strongly correlated with behavioral FIE performance. The orientation-dependent dynamic reorganization of effective connectivity indicates that the FIE is mediated by both qualitative and quantitative differences in upright and inverted face processing, helping to resolve a central debate over the mechanisms of the FIE.
人类识别物体的能力在各种视角下都非常强大，除非面孔是倒置呈现的。直立面孔和倒置面孔之间的这种面孔倒置效应（FIE）是由定性（不同机制）还是定量处理差异（共同机制内的程度问题）导致的，一直存在激烈争论。研究主要聚焦于面孔特异性脑区对面孔的优先反应，尽管人脸识别也涉及非面孔特异性脑区的非优先反应。通过使用贝叶斯模型选择的动态因果模型，我们在此表明，可分离的皮层通路负责在人脸识别分布式网络中FIE的定性和定量机制。当面孔直立时，早期视觉皮层（VC）以及枕颞面孔区和梭状面孔区（OFA、FFA）抑制了与枕外侧皮层（LO）的耦合，枕外侧皮层是物体处理的主要位点。相反，当面孔倒置时，它们并不抑制LO，而是增加了与顶内沟的耦合，顶内沟与视觉工作记忆有关。此外，我们发现直立和倒置面孔处理共同涉及由VC、OFA、FFA和额下回组成的面孔网络。具体而言，参与面孔基于部分处理的共同通路（VC - OFA）内的调制连接性与行为FIE表现密切相关。有效连接性的方向依赖性动态重组表明，FIE是由直立和倒置面孔处理中的定性和定量差异共同介导的，这有助于解决关于FIE机制的核心争论。
