Department of Psychology, Yale University, New Haven, CT 06520, USA.
Cereb Cortex. 2012 Feb;22(2):391-402. doi: 10.1093/cercor/bhr118. Epub 2011 Jun 13.
Ventral visual cortex contains specialized regions for particular object categories, but little is known about how these regions interact during object recognition. Here we examine how the face-selective fusiform gyrus (FG) and the scene-selective parahippocampal cortex (PHC) interact with each other and with the rest of the brain during different visual tasks. To assess these interactions, we developed a novel approach for identifying patterns of connectivity associated with specific task sets, independent of stimulus-evoked responses. We tested whether this "background connectivity" between the FG and PHC was modulated when subjects engaged in face and scene processing tasks. In contrast to what would be predicted from biased competition or intrinsic activity accounts, we found that the strength of FG-PHC background connectivity depended on which category was task relevant: connectivity increased when subjects attended to scenes (irrespective of whether a competing face was present) and decreased when subjects attended to faces (irrespective of competing scenes). We further discovered that posterior occipital cortex was correlated selectively with the FG during face tasks and the PHC during scene tasks. These results suggest that category specificity exists not only in which regions respond most strongly but also in how these and other regions interact.
腹侧视觉皮层包含专门用于特定对象类别的区域，但对于这些区域在对象识别过程中如何相互作用知之甚少。在这里，我们研究了在不同的视觉任务中，选择性的梭状回（FG）和场景选择性的旁海马回（PHC）如何与彼此以及大脑的其他部分相互作用。为了评估这些相互作用，我们开发了一种新的方法来识别与特定任务集相关的连接模式，而不依赖于刺激引起的反应。我们测试了当被试执行面孔和场景处理任务时，FG 和 PHC 之间的这种“背景连接”是否会被调节。与偏向竞争或内在活动解释所预测的相反，我们发现 FG-PHC 背景连接的强度取决于哪个类别是任务相关的：当被试关注场景时（无论是否存在竞争面孔），连接强度增加，而当被试关注面孔时（无论是否存在竞争场景），连接强度降低。我们进一步发现，后枕叶皮层在面孔任务中与 FG 选择性相关，在场景任务中与 PHC 选择性相关。这些结果表明，类别特异性不仅存在于反应最强的区域，还存在于这些区域和其他区域如何相互作用。
