Daprati E, Gentilucci M
Istituto di Fisiologia Umana, Università di Parma, Italy.
Neuropsychologia. 1997 Dec;35(12):1577-82. doi: 10.1016/s0028-3932(97)00061-4.
In the present study we attempted to determine the nature of the visual analysis that is performed on an object in order to grasp it. We required eight healthy subjects to reach and grasp a wooden bar which was superimposed over the shaft of the Müller-Lyer illusion. Vision of both the hand and the bar was allowed. Three different bar lengths were used. Two additional control tasks in which the subjects were required to reproduce the length of the shafts were carried out. The results showed that hand shaping while grasping the bar was influenced by the illusion configurations on which it was superimposed. However, this effect was smaller than that observed in the two tasks of length reproduction. These results support the notion that visual analysis performed on the object of a grasp movement is global and takes into account the object itself, as well as its relationships with surrounding cues. We propose, as suggested previously for reaching movements (Gentilucci, M. et al., Neuropsychologia, 1996, 34, 369-376), two partially independent stages during visuo-motor integration for grasping an object. In the first stage, the object is coded inside an object-centred frame of reference. In the second stage it is transposed in an egocentric frame of reference, in which the spatial relations between object and agent are computed. In this second stage the influence of cues surrounding the target is minimized.
在本研究中，我们试图确定为抓取物体而对其进行的视觉分析的性质。我们要求八名健康受试者伸手抓取一根叠加在缪勒-莱尔错觉图形轴上的木条。允许受试者同时看到手和木条。使用了三种不同的木条长度。还进行了另外两项对照任务，要求受试者重现图形轴的长度。结果表明，抓取木条时的手部塑形受到叠加在其上的错觉图形的影响。然而，这种影响比在两项长度重现任务中观察到的影响要小。这些结果支持了这样一种观点，即对抓握动作的物体进行的视觉分析是全局性的，会考虑物体本身及其与周围线索的关系。正如之前针对伸手动作所提出的那样（Gentilucci, M.等人，《神经心理学》，1996年，第34卷，第369 - 376页），我们提出在视觉 - 运动整合过程中抓取物体存在两个部分独立的阶段。在第一阶段，物体在以物体为中心的参照系中被编码。在第二阶段，它被转换到以自我为中心的参照系中，在这个参照系中计算物体与主体之间的空间关系。在第二阶段，目标周围线索的影响被最小化。
