School of Psychology, University of Plymouth, Drake Circus, Plymouth, Devon PL4 8AA, UK.
Neuroimage. 2012 Sep;62(3):1563-74. doi: 10.1016/j.neuroimage.2012.05.043. Epub 2012 May 24.
A negative event-related potential (ERP) at occipito-temporal sites peaking around 150-170 ms after stimulus onset (N170) is typically larger for faces than other object categories. Most theories interpret this finding as due to face-selective processing in occipito-temporal and temporal cortex. However, a controversial account recently attributed the N170 effect to differences in interstimulus variance (ISV) among the images typically used for face and object conditions and proposed that the earlier P1 instead indexes the categorical processes generally attributed to the N170. This ERP study aimed to test this account definitively by using conditions in which the same face and object were shown repeatedly, eliminating both physical and perceptual ISV. Fourier amplitude spectra of faces and objects were matched to equate basic low-level visual properties that may affect early ERPs such as the P1. Results demonstrate that i) face selectivity of the N170 is largely preserved across many object categories after abolishing ISV, and ii) stimulus category does not modulate the P1. This conclusively refutes the ISV account while strongly supporting category as a critical factor driving N170 face selectivity.
负事件相关电位（ERP）在刺激后 150-170 毫秒左右在枕颞部位达到峰值（N170），通常对于面部比其他物体类别更大。大多数理论将这一发现解释为枕颞和颞叶皮层对面部的选择性加工。然而，最近一个有争议的解释将 N170 效应归因于用于面部和物体条件的图像之间的刺激间方差（ISV）的差异，并提出较早的 P1 反而索引通常归因于 N170 的分类过程。这项 ERP 研究旨在通过使用相同的面部和物体重复显示的条件来明确测试这一解释，从而消除物理和感知 ISV。面部和物体的傅里叶幅度谱进行匹配，以平衡可能影响早期 ERP（如 P1）的基本低级视觉属性。结果表明，i）在消除 ISV 后，N170 对面部的选择性在许多物体类别中基本得到保留，ii）刺激类别不调节 P1。这一结论有力地反驳了 ISV 解释，同时强烈支持类别是驱动 N170 对面部选择性的关键因素。
