Athinoula A Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, MA 02129, USA.
Proc Natl Acad Sci U S A. 2011 Feb 22;108(8):3389-94. doi: 10.1073/pnas.1013760108. Epub 2011 Feb 7.
Objects are more easily recognized in their typical context. However, is contextual information activated early enough to facilitate the perception of individual objects, or is contextual facilitation caused by postperceptual mechanisms? To elucidate this issue, we first need to study the temporal dynamics and neural interactions associated with contextual processing. Studies have shown that the contextual network consists of the parahippocampal, retrosplenial, and medial prefrontal cortices. We used functional MRI, magnetoencephalography, and phase synchrony analyses to compare the neural response to stimuli with strong or weak contextual associations. The context network was activated in functional MRI and preferentially synchronized in magnetoencephalography (MEG) for stimuli with strong contextual associations. Phase synchrony increased early (150-250 ms) only when it involved the parahippocampal cortex, whereas retrosplenial-medial prefrontal cortices synchrony was enhanced later (300-400 ms). These results describe the neural dynamics of context processing and suggest that context is activated early during object perception.
物体在其典型的环境中更容易被识别。然而，环境信息是否能提前激活，从而促进个体物体的感知，或者环境促进是由知觉后机制引起的？为了解决这个问题，我们首先需要研究与上下文处理相关的时间动态和神经相互作用。研究表明，上下文网络由海马旁回、后扣带回和内侧前额叶皮层组成。我们使用功能磁共振成像、脑磁图和相位同步分析来比较对具有强或弱上下文关联的刺激的神经反应。功能磁共振成像中激活了上下文网络，对具有强上下文关联的刺激在脑磁图（MEG）中优先同步。相位同步仅在涉及海马旁回时早期（150-250ms）增加，而扣带回-内侧前额叶皮质的同步性则在后期（300-400ms）增强。这些结果描述了上下文处理的神经动力学，并表明在物体感知过程中，上下文会提前被激活。
