Gamble Christine M, Song Joo-Hyun
Department of Cognitive, Linguistic, & Psychological Sciences, Brown University, Providence, RI,
Department of Cognitive, Linguistic, & Psychological Sciences, Brown University, Providence, RI, USABrown Institute for Brain Science, Brown University, Providence, RI,
J Vis. 2017 Mar 1;17(3):23. doi: 10.1167/17.3.23.
In everyday behavior, two of the most common visually guided actions-eye and hand movements-can be performed independently, but are often synergistically coupled. In this study, we examine whether the same visual representation is used for different stages of saccades and pointing, namely movement preparation and execution, and whether this usage is consistent between independent and naturalistic coordinated eye and hand movements. To address these questions, we used the Ponzo illusion to dissociate the perceived and physical sizes of visual targets and measured the effects on movement preparation and execution for independent and coordinated saccades and pointing. During independent movements, we demonstrated that both physically and perceptually larger targets produced faster preparation for both effectors. Furthermore, participants who showed a greater influence of the illusion on saccade preparation also showed a greater influence on pointing preparation, suggesting that a shared mechanism involved in preparation across effectors is influenced by illusions. However, only physical but not perceptual target sizes influenced saccade and pointing execution. When pointing was coordinated with saccades, we observed different dynamics: pointing no longer showed modulation from illusory size, while saccades showed illusion modulation for both preparation and execution. Interestingly, in independent and coordinated movements, the illusion modulated saccade preparation more than pointing preparation, with this effect more pronounced during coordination. These results suggest a shared mechanism, dominated by the eyes, may underlie visually guided action preparation across effectors. Furthermore, the influence of illusions on action may operate within such a mechanism, leading to dynamic interactions between action modalities based on task demands.
在日常行为中，两种最常见的视觉引导动作——眼睛和手部运动——可以独立执行，但它们通常会协同耦合。在本研究中，我们探究在扫视和指向的不同阶段，即运动准备和执行阶段，是否使用相同的视觉表征，以及这种使用在独立的和自然协调的眼手运动之间是否一致。为了解决这些问题，我们利用庞佐错觉来区分视觉目标的感知大小和实际大小，并测量其对独立和协调扫视及指向的运动准备和执行的影响。在独立运动过程中，我们证明，无论是实际还是感知上更大的目标，都会使两种效应器的准备速度更快。此外，在扫视准备中受错觉影响更大的参与者，在指向准备中也表现出更大的影响，这表明跨效应器参与准备的共享机制会受错觉影响。然而，只有实际目标大小而非感知目标大小会影响扫视和指向的执行。当指向与扫视协调时，我们观察到了不同的动态变化：指向不再受虚幻大小的调制影响，而扫视在准备和执行阶段均表现出错觉调制。有趣的是，在独立和协调运动中，错觉对扫视准备的调制作用比对指向准备的调制作用更大，且这种效应在协调过程中更为明显。这些结果表明，一种以眼睛为主导的共享机制可能是跨效应器视觉引导动作准备的基础。此外，错觉对动作的影响可能在这样一种机制内起作用，从而导致基于任务需求的动作模式之间的动态相互作用。
