The magnocellular system has been implicated in the rapid processing of facial emotions, such as fear. Of the various anatomical possibilities, the retino-colliculo-pulvinar route to the amygdala is currently favored. However, it is not clear whether and when amygdala arousal activates the primary visual cortex (V1). Non-linear visual evoked potentials provide a well-accepted technique for examining temporal processing in the magnocellular and parvocellular pathways in the visual cortex. Here, we investigated the relationship between facial emotion processing and the separable magnocellular (K2.1) and parvocellular (K2.2) components of the second-order non-linear multifocal visual evoked potential responses recorded from the occipital scalp (OZ). Stimuli comprised pseudorandom brightening/darkening of fearful, happy, neutral faces (or no face) with surround patches decorrelated from the central face-bearing patch. For the central patch, the spatial contrast of the faces was 30% while the modulation of the per-pixel brightening/darkening was uniformly 10% or 70%. From 14 neurotypical young adults, we found a significant interaction between emotion and contrast in the magnocellularly driven K2.1 peak amplitudes, with greater K2.1 amplitudes for fearful (vs. happy) faces at 70% temporal contrast condition. Taken together, our findings suggest that facial emotional information is present in early V1 processing as conveyed by the M pathway, and more activated for fearful as opposed to happy and neutral faces. An explanation is offered in terms of the contest between feedback and response gain modulation models.

中文翻译：

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枕大细胞 VEP 非线性显示对比度和面部情绪之间的短延迟相互作用

大细胞系统与面部情绪的快速处理有关，例如恐惧。在各种解剖可能性中，目前偏向于通往杏仁核的视网膜-丘脑-丘脑路径。然而，尚不清楚杏仁核唤醒是否以及何时激活初级视觉皮层 (V1)。非线性视觉诱发电位提供了一种被广泛接受的技术，用于检查视觉皮层中大细胞和细小细胞通路的时间处理。在这里，我们研究了面部情绪处理与从枕骨头皮 (OZ) 记录的二阶非线性多焦视觉诱发电位反应的可分离大细胞 (K2.1) 和小细胞 (K2.2) 成分之间的关​​系。刺激包括恐惧、快乐、中性面（或无面），周围面片与中央面部贴片去相关。对于中心斑块，人脸的空间对比度为 30%，而每像素增亮/变暗的调制均匀为 10% 或 70%。从 14 名神经典型的年轻人中，我们发现情绪和对比度在大细胞驱动的 K2.1 峰值振幅之间存在显着的相互作用，在 70% 的时间对比度条件下，恐惧（与快乐）面孔的 K2.1 振幅更大。综上所述，我们的研究结果表明，面部情绪信息存在于由 M 通路传达的早期 V1 处理中，与快乐和中性面孔相比，在恐惧时更活跃。在反馈和响应增益调制模型之间的竞争方面提供了解释。