Laboratory for Cognitive Neuroscience, Graduate School of Frontier Biosciences, Osaka University, 1-4 Yamadaoka, Suita, Osaka 565-0871, Japan.
Center for Information and Neural Networks, National Institute of Information and Communications Technology and Osaka University, 1-4 Yamadaoka, Suita, Osaka 565-0871, Japan.
Cereb Cortex. 2023 Jan 5;33(3):895-915. doi: 10.1093/cercor/bhac109.
A subcortical pathway through the superior colliculus and pulvinar has been proposed to provide the amygdala with rapid but coarse visual information about emotional faces. However, evidence for short-latency, facial expression-discriminating responses from individual amygdala neurons is lacking; even if such a response exists, how it might contribute to stimulus detection is unclear. Also, no definitive anatomical evidence is available for the assumed pathway. Here we showed that ensemble responses of amygdala neurons in monkeys carried robust information about open-mouthed, presumably threatening, faces within 50 ms after stimulus onset. This short-latency signal was not found in the visual cortex, suggesting a subcortical origin. Temporal analysis revealed that the early response contained excitatory and suppressive components. The excitatory component may be useful for sending rapid signals downstream, while the sharpening of the rising phase of later-arriving inputs (presumably from the cortex) by the suppressive component might improve the processing of facial expressions over time. Injection of a retrograde trans-synaptic tracer into the amygdala revealed presumed monosynaptic labeling in the pulvinar and disynaptic labeling in the superior colliculus, including the retinorecipient layers. We suggest that the early amygdala responses originating from the colliculo-pulvino-amygdalar pathway play dual roles in threat detection.
已经提出了一条通过上丘和丘脑枕的皮质下通路，为杏仁核提供关于情绪面孔的快速但粗略的视觉信息。然而，缺乏来自单个杏仁核神经元的具有短潜伏期、能够区分面部表情的反应的证据；即使存在这样的反应，它如何有助于刺激检测也不清楚。此外，对于假设的通路，还没有明确的解剖学证据。在这里，我们表明，猴子杏仁核神经元的群体反应在刺激开始后 50 毫秒内携带关于张口的、可能具有威胁性的面孔的强大信息。在视觉皮层中没有发现这种短潜伏期信号，这表明它来自皮质下。时间分析表明，早期反应包含兴奋性和抑制性成分。兴奋性成分可能有助于向下游发送快速信号，而抑制性成分对后期到达的输入（可能来自皮层）上升相位的锐化可能会随着时间的推移改善面部表情的处理。将逆行跨突触示踪剂注入杏仁核后，在丘脑枕中发现了假定的单突触标记，在上丘中发现了双突触标记，包括视网膜接收层。我们认为，起源于丘-枕-杏仁核通路的早期杏仁核反应在威胁检测中发挥双重作用。
