Although the recognition of facial expressions seems automatic and effortless, discrimination of expressions can still be error prone. Common errors are often due to visual similarities between some expressions (e.g., fear and surprise). However, little is known about the neural mechanisms underlying such a confusion effect. To address this question, we recorded the magnetoencephalography (MEG) while participants judged facial expressions that were either easily confused with or easily distinguished from other expressions. The results showed that the fusiform face area (FFA), rather than the posterior superior temporal sulcus (pSTS), played a preponderant role in discriminating confusable facial expressions. No difference between high confusion and low confusion conditions was observed on the M170 component in either the FFA or the pSTS, whilst a difference between two conditions started to emerge in the late positive potential (LPP), with the low confusion condition eliciting a larger LPP amplitude in the FFA. In addition, the power of delta was stronger in the time window of LPP component. This confusion effect was reflected in the FFA, which might be associated with the perceptual-to-conceptual shift.

尽管对面部表情的识别似乎是自动的且毫不费力的，但是对表情的辨别仍然容易出错。常见错误通常是由于某些表达之间的视觉相似性（例如，恐惧和惊奇）。然而，对于这种混淆作用的神经机制知之甚少。为了解决这个问题，我们记录了脑磁图（MEG），同时参与者判断面部表情容易与其他表情混淆或容易区别。结果表明，梭形脸部区域（FFA）而不是后颞颞沟（pSTS）在区分容易混淆的面部表情方面起着主要作用。在FFA或pSTS中，M170组件上没有发现高混淆条件和低混淆条件之间的差异，而两个条件之间的差异开始出现在晚期正电位（LPP）中，而低混淆条件则导致FFA中的LPP幅度更大。此外，在LPP组件的时间窗口中，delta的功效更强。这种混淆效应反映在FFA中，这可能与知觉到观念的转变有关。