McGovern Institute for Brain Research, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
J Neurosci. 2011 Aug 3;31(31):11305-12. doi: 10.1523/JNEUROSCI.1935-11.2011.
Electrophysiological and behavioral studies in many species have demonstrated mirror-image confusion for objects, perhaps because many objects are vertically symmetric (e.g., a cup is the same cup when seen in left or right profile). In contrast, the navigability of a scene changes when it is mirror reversed, and behavioral studies reveal high sensitivity to this change. Thus, we predicted that representations in object-selective cortex will be unaffected by mirror reversals, whereas representations in scene-selective cortex will be sensitive to such reversals. To test this hypothesis, we ran an event-related functional magnetic resonance imaging adaptation experiment in human adults. Consistent with our prediction, we found tolerance to mirror reversals in one object-selective region, the posterior fusiform sulcus, and a strong sensitivity to these reversals in two scene-selective regions, the transverse occipital sulcus and the retrosplenial complex. However, a more posterior object-selective region, the lateral occipital sulcus, showed sensitivity to mirror reversals, suggesting that the sense information that distinguishes mirror images is represented at earlier stages in the object-processing hierarchy. Moreover, one scene-selective region (the parahippocampal place area or PPA) was tolerant to mirror reversals. This last finding challenges the hypothesis that the PPA is involved in navigation and reorientation and suggests instead that scenes, like objects, are processed by distinct pathways guiding recognition and action.
在许多物种的电生理和行为研究中，已经证明了物体的镜像混淆，这可能是因为许多物体是垂直对称的（例如，杯子从左右轮廓看都是同一个杯子）。相比之下，当场景被镜像反转时，其可导航性会发生变化，行为研究也揭示了对这种变化的高度敏感性。因此，我们预测，在物体选择性皮层中的表示将不受镜像反转的影响，而在场景选择性皮层中的表示将对这种反转敏感。为了验证这一假设，我们在成年人类中进行了一项与事件相关的功能磁共振成像适应实验。与我们的预测一致，我们在一个物体选择性区域（后梭状回沟）中发现了对镜像反转的容忍，而在两个场景选择性区域（横向枕沟和后扣带回复合体）中则对这些反转非常敏感。然而，一个更靠后的物体选择性区域（外侧枕沟）对镜像反转表现出敏感性，这表明区分镜像的感觉信息是在物体处理层次结构的早期阶段表示的。此外，一个场景选择性区域（旁海马区位置区或 PPA）对镜像反转具有容忍性。最后一个发现挑战了 PPA 参与导航和重新定向的假说，表明场景和物体一样，是通过不同的路径来处理的，这些路径指导着识别和行动。
