Division of Biology, California Institute of Technology, Pasadena, CA, 91125, USA.
Laboratory of Cognitive Neuroscience, Brain Mind Institute, Faculty of Life Sciences, Swiss Federal Institute of Technology (EPFL), Geneva, Switzerland.
Sci Rep. 2019 Mar 14;9(1):4567. doi: 10.1038/s41598-019-38654-z.
Integrating objects with their context is a key step in interpreting complex visual scenes. Here, we used functional Magnetic Resonance Imaging (fMRI) while participants viewed visual scenes depicting a person performing an action with an object that was either congruent or incongruent with the scene. Univariate and multivariate analyses revealed different activity for congruent vs. incongruent scenes in the lateral occipital complex, inferior temporal cortex, parahippocampal cortex, and prefrontal cortex. Importantly, and in contrast to previous studies, these activations could not be explained by task-induced conflict. A secondary goal of this study was to examine whether processing of object-context relations could occur in the absence of awareness. We found no evidence for brain activity differentiating between congruent and incongruent invisible masked scenes, which might reflect a genuine lack of activation, or stem from the limitations of our study. Overall, our results provide novel support for the roles of parahippocampal cortex and frontal areas in conscious processing of object-context relations, which cannot be explained by either low-level differences or task demands. Yet they further suggest that brain activity is decreased by visual masking to the point of becoming undetectable with our fMRI protocol.
将物体与其上下文进行整合是解释复杂视觉场景的关键步骤。在这里，我们让参与者观看描绘一个人用与场景一致或不一致的物体执行动作的视觉场景，同时使用功能磁共振成像 (fMRI)。单变量和多变量分析显示，在外侧枕叶复合体、下颞叶皮层、海马旁回和前额叶皮层中，一致和不一致的场景有不同的活动。重要的是，与之前的研究相比，这些激活不能用任务引起的冲突来解释。这项研究的第二个目标是检查在没有意识的情况下是否可以处理物体-上下文关系。我们没有发现大脑活动区分一致和不一致的不可见掩蔽场景的证据，这可能反映出真正的缺乏激活，或者源于我们研究的局限性。总的来说，我们的结果为海马旁回和额叶区域在有意识地处理物体-上下文关系方面提供了新的支持，这不能用低水平差异或任务需求来解释。然而，它们进一步表明，大脑活动在视觉掩蔽的作用下降低到了我们的 fMRI 协议无法检测到的程度。
