PDF(Pubmed)
Abstract：
The center-periphery visual field axis guides early visual system organization with enhanced resources devoted to central vision leading to reduced peripheral performance relative to that of central vision (i.e., behavioral eccentricity effect) for many visual functions. The center-periphery organization extends to high-order visual cortex where, for example, the well-studied face-sensitive fusiform face area (FFA) shows sensitivity to central vision and the place-sensitive parahippocampal place area (PPA) shows sensitivity to peripheral vision. As we have recently found that face perception is more sensitive to eccentricity than place perception, here we examined whether these behavioral findings reflect differences in FFA\'s and PPA\'s sensitivities to eccentricity. We assumed FFA would show higher sensitivity to eccentricity than PPA would, but that both regions\' modulation by eccentricity would be invariant to the viewed category. We parametrically investigated (fMRI, n = 32) how FFA\'s and PPA\'s activations are modulated by eccentricity (≤8°) and category (upright/inverted faces/houses) while keeping stimulus size constant. As expected, FFA showed an overall higher sensitivity to eccentricity than PPA. However, both regions\' activation modulations by eccentricity were dependent on the viewed category. In FFA, a reduction of activation with growing eccentricity (\"BOLD eccentricity effect\") was found (with different amplitudes) for all categories. In PPA however, qualitatively different BOLD eccentricity effect modulations were found (e.g., at 8° mild BOLD eccentricity effect for houses but a reverse BOLD eccentricity effect for faces and no modulation for inverted faces). Our results emphasize that peripheral vision investigations are critical to further our understanding of visual processing.
摘要：
中心-外围视野轴引导早期视觉系统组织，增强了用于中心视觉的资源，导致相对于中心视觉的外围性能降低（即，行为偏心效应)对许多视觉功能。中心-外围组织延伸到高阶视觉皮层，例如,经过充分研究的面部敏感梭形面部区域(FFA)显示对中央视觉的敏感性,位置敏感的海马旁区域(PPA)显示对周边视觉的敏感性.正如我们最近发现的那样，面部感知比位置感知对偏心更敏感，在这里，我们研究了这些行为发现是否反映了FFA和PPA对偏心敏感性的差异。我们假设FFA对偏心的敏感度高于PPA，但这两个区域的偏心调制对于观看的类别是不变的。我们进行了参数调查(功能磁共振成像，n=32）如何通过偏心率（≤8°）和类别（直立/倒置面/房屋）调节FFA和PPA的激活，同时保持刺激大小恒定。不出所料,FFA对偏心率的总体敏感性高于PPA。然而,这两个区域的偏心激活调制都取决于所查看的类别。在FFA中，在所有类别中，都发现了随着偏心度增加（“BOLD偏心效应”）的激活减少（幅度不同）。然而，在PPA中，发现了质量上不同的BOLD偏心效应调制(例如，在8°时，房屋具有轻度的BOLD偏心效应，但在面部具有反向的BOLD偏心效应，而在倒置的面部没有调制）。我们的结果强调，周边视觉调查对于进一步了解视觉处理至关重要。
