Perception of object motion in three-dimensional space induced by cast shadows
Perception of object motion in three-dimensional space induced by cast shadows
复制标题
DOI：
10.1016/j.neuroimage.2010.07.075
复制
发表时间：
2011-01-01
期刊：
影响因子：
5.7
通讯作者：
Taira, Masato
中科院分区：
文献类型：
--
作者：
Katsuyama, Narumi;Usui, Nobuo;Taira, Masato
在三维（3D）视觉中，投影可以作为显著的深度线索。利用运动错觉，根据投射阴影轨迹的斜率，球被感知到在底部深度滚动或在前平面流动，我们利用功能磁共振成像技术研究了基于投射阴影的3D视觉的皮层机制。当向被试呈现原错觉的修改版本，即阴影轨迹的斜率（阴影斜率）从与球的轨迹相同的斜率到水平的5步变化时，他们感知到的球轨迹随着阴影斜率的变化逐渐从底部滚动到前平面浮动。这一观察结果表明，在这种错觉中，对球轨迹的感知受到投射阴影运动的强烈影响。在fMRI研究中，研究了在观察幻觉电影时大脑皮层的活动。我们发现双侧枕后沟（POS）和右腹楔前叶出现与错觉中投影引起的球轨迹感知相关的激活。在这些区域中，我们认为正确的POS可能涉及根据给定的球和阴影之间的空间关系来推断球的轨迹。我们目前的结果表明，内侧顶叶皮层的后部可能与投射阴影的3D视觉有关。(C) 2010爱思唯尔公司版权所有。
Cast shadows can be salient depth cues in three-dimensional (3D) vision. Using a motion illusion in which a ball is perceived to roll in depth on the bottom or to flow in the front plane depending on the slope of the trajectory of its cast shadow, we investigated cortical mechanisms underlying 3D vision based on cast shadows using fMRI techniques. When modified versions of the original illusion, in which the slope of the shadow trajectory (shadow slope) was changed in 5 steps from the same one as the ball trajectory to the horizontal, were presented to participants, their perceived ball trajectory shifted gradually from rolling on the bottom to floating in the front plane as the change of the shadow slope. This observation suggests that the perception of the ball trajectory in this illusion is strongly affected by the motion of the cast shadow. In the fMRI study, cortical activity during observation of the movies of the illusion was investigated. We found that the bilateral posterior-occipital sulcus (POS) and right ventral precuneus showed activation related to the perception of the ball trajectory induced by the cast shadows in the illusion. Of these areas, it was suggested that the right POS may be involved in the inferring of the ball trajectory by the given spatial relation between the ball and the shadow. Our present results suggest that the posterior portion of the medial parietal cortex may be involved in 3D vision by cast shadows. (C) 2010 Elsevier Inc. All rights reserved.