Barnett-Cowan Michael, Harris Laurence R
Multisensory Integration Laboratory, Centre for Vision Research, Department of Psychology, York University, 4700 Keele Street, Toronto, Ontario, Canada.
Brain Res. 2008 Nov 25;1242:231-43. doi: 10.1016/j.brainres.2008.07.075. Epub 2008 Jul 29.
Do physical tilt and tilt of the visual environment affect perception of allocentric and egocentric space? We addressed this question using two perceptual-motor tasks: alignment of a tactile rod (ROD) and saccadic eye movements (EM). Nine participants indicated the vertical axis of their heads (egocentric task), as well as the direction of gravity (allocentric task). Head orientation (+/-60 degrees and 0 degrees) and visual environment orientation (+/-120 degrees, +/-60 degrees and 0 degrees) were independently manipulated in the fronto-planar roll plane. ROD and EM estimates of both allocentric and egocentric reference directions varied with head and room orientation. Physical tilt dominated allocentric estimates in the dark where overestimates of physical tilt were noted up to 11 degrees using both measures. Allocentric ROD and EM estimates were significantly correlated across all head orientations (r=.70, p<.01) but only when upright for egocentric estimates (r=.38, p<.01). The relative contributions of the visual environment, gravity's direction and long-body axis to the estimation of allocentric and egocentric directions were determined by vector modeling. This modeling found that vision determined about 14% of the allocentric ROD and EM estimates, that the long-axis body reference played no discernible role, and that the largest factor was gravity, the effective direction of which was non-veridical. For egocentric estimates, vision contributed about 3% with the largest factor being the body reference. We conclude that perception of allocentric and egocentric space is likely influenced by multiple senses that define common egocentric and allocentric frames of reference accessible for saccadic and tactile estimates of perceived self-orientation.
身体倾斜和视觉环境倾斜会影响对异我中心空间和自我中心空间的感知吗？我们通过两项感知运动任务来探讨这个问题：触觉杆校准（ROD）和眼球扫视运动（EM）。九名参与者分别指出其头部的垂直轴（自我中心任务）以及重力方向（异我中心任务）。在额面翻滚平面中，独立操纵头部方向（±60度和0度）和视觉环境方向（±120度、±60度和0度）。ROD和EM对异我中心和自我中心参考方向的估计均随头部和房间方向而变化。在黑暗中，身体倾斜主导了异我中心估计，使用这两种测量方法时，身体倾斜的高估可达11度。在所有头部方向上，异我中心ROD和EM估计均显著相关（r = 0.70，p < 0.01），但仅在自我中心估计为直立时相关（r = 0.38，p < 0.01）。通过向量建模确定了视觉环境、重力方向和身体长轴对异我中心和自我中心方向估计的相对贡献。该建模发现，视觉决定了约14%的异我中心ROD和EM估计，身体长轴参考没有明显作用，最大的因素是重力，其有效方向并非真实方向。对于自我中心估计，视觉贡献约3%，最大因素是身体参考。我们得出结论，异我中心和自我中心空间的感知可能受到多种感官的影响，这些感官定义了共同的自我中心和异我中心参考框架，可用于对感知到的自我定向进行眼球扫视和触觉估计。
