Le Quang Van, Le Quan Van, Nishimaru Hiroshi, Matsumoto Jumpei, Takamura Yusaku, Hori Etsuro, Maior Rafael S, Tomaz Carlos, Ono Taketoshi, Nishijo Hisao
System Emotional Science, Faculty of Medicine, University of Toyama, Toyama, Japan.
Primate Center and Laboratory of Neurosciences and Behavior, Department of Physiological Sciences, Institute of Biology, University of Brasília, Brasilia, Brazil.
Front Syst Neurosci. 2020 Feb 6;14:5. doi: 10.3389/fnsys.2020.00005. eCollection 2020.
Human babies respond preferentially to faces or face-like images. It has been proposed that an innate and rapid face detection system is present at birth before the cortical visual pathway is developed in many species, including primates. However, in primates, the visual area responsible for this process is yet to be unraveled. We hypothesized that the superior colliculus (SC) that receives direct and indirect retinal visual inputs may serve as an innate rapid face-detection system in primates. To test this hypothesis, we examined the responsiveness of monkey SC neurons to first-order information of faces required for face detection (basic spatial layout of facial features including eyes, nose, and mouth), by analyzing neuronal responses to line drawing images of: (1) face-like patterns with contours and properly placed facial features; (2) non-face patterns including face contours only; and (3) nonface random patterns with contours and randomly placed face features. Here, we show that SC neurons respond stronger and faster to upright and inverted face-like patterns compared to the responses to nonface patterns, regardless of contrast polarity and contour shapes. Furthermore, SC neurons with central receptive fields (RFs) were more selective to face-like patterns. In addition, the population activity of SC neurons with central RFs can discriminate face-like patterns from nonface patterns as early as 50 ms after the stimulus onset. Our results provide strong neurophysiological evidence for the involvement of the primate SC in face detection and suggest the existence of a broadly tuned template for face detection in the subcortical visual pathway.
人类婴儿会优先对面部或类似面部的图像做出反应。有人提出，在包括灵长类动物在内的许多物种中，出生时就存在一种先天且快速的面部检测系统，此时皮质视觉通路尚未发育。然而，在灵长类动物中，负责这一过程的视觉区域尚未明确。我们假设，接受视网膜直接和间接视觉输入的上丘（SC）可能是灵长类动物先天的快速面部检测系统。为了验证这一假设，我们通过分析神经元对以下线条画图像的反应，研究了猴子上丘神经元对面部检测所需的面部一阶信息（包括眼睛、鼻子和嘴巴的面部特征的基本空间布局）的反应：（1）具有轮廓且面部特征位置恰当的类似面部的图案；（2）仅包括面部轮廓的非面部图案；（3）具有轮廓且面部特征随机放置的非面部随机图案。在此，我们表明，与对非面部图案的反应相比，上丘神经元对直立和倒置的类似面部图案的反应更强、更快，且与对比度极性和轮廓形状无关。此外，具有中央感受野（RFs）的上丘神经元对类似面部的图案更具选择性。此外，具有中央RFs的上丘神经元群体活动在刺激开始后50毫秒就能将类似面部的图案与非面部图案区分开来。我们的结果为灵长类动物上丘参与面部检测提供了有力的神经生理学证据，并表明在皮质下视觉通路中存在一个广泛调谐的面部检测模板。
