Faculty of Psychology and Educational Sciences, Research Institute for Psychological Science (IPSY), UC Louvain, Louvain-la-Neuve, Belgium.
Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht University, Maastricht, the Netherlands.
PLoS One. 2020 Mar 18;15(3):e0229185. doi: 10.1371/journal.pone.0229185. eCollection 2020.
Orientation selectivity is a fundamental property of primary visual encoding. High-level processing stages also show some form of orientation dependence, with face identification preferentially relying on horizontally-oriented information. How high-level orientation tuning emerges from primary orientation biases is unclear. In the same group of participants, we derived the orientation selectivity profile at primary and high-level visual processing stages using a contrast detection and an identity matching task. To capture the orientation selectivity profile, we calculated the difference in performance between all tested orientations (0, 45, 90, and 135°) for each task and for upright and inverted faces, separately. Primary orientation selectivity was characterized by higher sensitivity to oblique as compared to cardinal orientations. The orientation profile of face identification showed superior horizontal sensitivity to face identity. In each task, performance with upright and inverted faces projected onto qualitatively similar a priori models of orientation selectivity. Yet the fact that the orientation selectivity profiles of contrast detection in upright and inverted faces correlated significantly while such correlation was absent for identification indicates a progressive dissociation of orientation selectivity profiles from primary to high-level stages of orientation encoding. Bayesian analyses further indicate a lack of correlation between the orientation selectivity profiles in the contrast detection and face identification tasks, for upright and inverted faces. From these findings, we conclude that orientation selectivity shows distinct profiles at primary and high-level stages of face processing and that a transformation must occur from general cardinal attenuation when processing basic properties of the face image to horizontal tuning when encoding more complex properties such as identity.
方向选择性是初级视觉编码的基本属性。高级处理阶段也表现出某种形式的方向依赖性，面部识别优先依赖于水平方向的信息。从初级方向偏差中如何出现高级方向调谐尚不清楚。在同一组参与者中，我们使用对比度检测和身份匹配任务在初级和高级视觉处理阶段推导出方向选择性轮廓。为了捕获方向选择性轮廓，我们分别为每个任务和正立和倒立的面孔计算了所有测试方向（0、45、90 和 135°）之间的性能差异。初级方向选择性的特征是对斜向方向的敏感性高于对基数方向的敏感性。面孔识别的方向轮廓表现出对水平方向的敏感性更高，有利于面孔身份。在每个任务中，正立和倒立面孔的性能投射到定性相似的先验方向选择性模型上。然而，对比度检测中直立和倒立面孔的方向选择性轮廓之间存在显著相关性，而识别中则不存在这种相关性，这表明从初级到高级方向编码阶段，方向选择性轮廓逐渐分离。贝叶斯分析进一步表明，对于直立和倒立的面孔，对比度检测和面孔识别任务中的方向选择性轮廓之间没有相关性。从这些发现中，我们得出结论，方向选择性在面孔处理的初级和高级阶段表现出不同的轮廓，并且在处理面孔图像的基本属性时，必须从一般基数衰减转换为编码更复杂属性（如身份）时的水平调谐。
