Division of Biological Psychology and Neuropsychology, University of Hamburg, 20146 Hamburg, Germany.
Proc Natl Acad Sci U S A. 2013 Oct 15;110(42):16760-5. doi: 10.1073/pnas.1309963110. Epub 2013 Sep 9.
The aim of the study was to identify possible sensitive phases in the development of the processing system for human faces. We tested the neural processing of faces in 11 humans who had been blind from birth and had undergone cataract surgery between 2 mo and 14 y of age. Pictures of faces and houses, scrambled versions of these pictures, and pictures of butterflies were presented while event-related potentials were recorded. Participants had to respond to the pictures of butterflies (targets) only. All participants, even those who had been blind from birth for several years, were able to categorize the pictures and to detect the targets. In healthy controls and in a group of visually impaired individuals with a history of developmental or incomplete congenital cataracts, the well-known enhancement of the N170 (negative peak around 170 ms) event-related potential to faces emerged, but a face-sensitive response was not observed in humans with a history of congenital dense cataracts. By contrast, this group showed a similar N170 response to all visual stimuli, which was indistinguishable from the N170 response to faces in the controls. The face-sensitive N170 response has been associated with the structural encoding of faces. Therefore, these data provide evidence for the hypothesis that the functional differentiation of category-specific neural representations in humans, presumably involving the elaboration of inhibitory circuits, is dependent on experience and linked to a sensitive period. Such functional specialization of neural systems seems necessary to archive high processing proficiency.
本研究旨在确定人类面孔处理系统发育过程中的可能敏感阶段。我们测试了 11 名先天性失明并在 2 个月至 14 岁之间接受白内障手术的人的面孔的神经处理。在记录事件相关电位的同时，呈现面孔和房屋的图片、这些图片的乱序版本以及蝴蝶的图片。参与者只能对面孔的蝴蝶图片（目标）做出反应。所有参与者，即使是那些从出生起就失明多年的人，都能够对面孔进行分类并检测到目标。在健康对照组和一组有发育性或不完全性先天性白内障病史的视力障碍个体中，出现了众所周知的 N170（负峰约 170 毫秒）事件相关电位对面孔的增强，但在有先天性致密白内障病史的个体中未观察到对面孔的敏感反应。相比之下，该组对所有视觉刺激表现出相似的 N170 反应，与对照组中对面孔的 N170 反应无法区分。对面孔敏感的 N170 反应与面孔的结构编码有关。因此，这些数据为假设提供了证据，即人类特定类别神经表现的功能分化，推测涉及抑制性回路的细化，取决于经验并与敏感时期相关。这种神经系统的功能专业化似乎是实现高处理效率所必需的。
