Séverac Cauquil Alexandra, Trotter Yves, Taylor Margot J
Centre de Recherche Cerveau et Cognition, UMR 5549 UPS/CNRS, Université Paul Sabatier Toulouse III, 133 route de Narbonne, 31062, Toulouse cedex 4, France.
Exp Brain Res. 2006 Apr;170(4):457-63. doi: 10.1007/s00221-005-0229-1. Epub 2005 Nov 24.
The present study investigated the cortical processing of three-dimensional (3D) perspective cues in humans, to determine how the brain computes depth from a bidimensional retinal image. We recorded visual evoked potentials in 12 subjects in response to flat and in-perspective stimuli, which evoked biphasic potentials over posterior electrodes. The first, positive component (P1, at 90 ms) was not sensitive to perspective, while the second, negative peak (N1 at approximately 150 ms) was significantly larger for 3D stimuli, regardless of attention. The amplitude increase due to perspective was seen on all posterior electrodes, but was largest over the right hemisphere, particularly at parietal sites. Source modeling low-resolution electromagnetic tomography (LORETA) confirmed that among the different areas participating in two- and three-dimensional stimuli processing, the right parietal source is the most enhanced by perspective depth cues. We conclude that the extraction of depth from perspective cues occurs at a second level of stimulus processing, by increasing the activity of the regions involved in 2D stimuli processing, particularly in the right hemisphere, possibly through feedback loops from higher cortical areas. These modulations would participate in the fine-tuned analysis of the 3D features of stimuli.
本研究调查了人类对三维（3D）透视线索的皮层处理过程，以确定大脑如何从二维视网膜图像中计算深度。我们记录了12名受试者对平面和透视刺激的视觉诱发电位，这些刺激在后部电极上诱发了双相电位。第一个正成分（P1，在90毫秒时）对透视不敏感，而第二个负峰（N1在大约150毫秒时）在3D刺激时显著更大，与注意力无关。透视引起的振幅增加在所有后部电极上都可见，但在右半球最大，特别是在顶叶部位。源模型低分辨率电磁断层扫描（LORETA）证实，在参与二维和三维刺激处理的不同区域中，右顶叶源在透视深度线索的作用下增强最为明显。我们得出结论，从透视线索中提取深度发生在刺激处理的第二阶段，通过增加参与二维刺激处理区域的活动，特别是在右半球，可能是通过来自更高皮层区域的反馈回路实现的。这些调制将参与对刺激三维特征的精细分析。
