The category-sensitive and orientation-sensitive N170 adaptation in faces revealed by comparison with Chinese characters.

By comparing faces with Chinese characters, the category-sensitive and orientation-sensitive N170 adaptation effects were examined when the stimuli were adapted by category (within vs. between) and orientation (same vs. different). The category-sensitive N170 adaptation was present for both faces and characters, supporting the assertion that the perception of faces and characters recruits domain-specific processing rather than general processing of visual expertise. In addition, the orientation-sensitive N170 adaptation was present only for faces but not for characters, suggesting that only faces recruit orientation-specific processing. More importantly, the orientation-sensitive N170 adaptation was not only present for inverted faces but also for upright faces, indicating that there are distinct neuron populations respectively sensitive to upright and inverted faces.