Li Jirui, Sajad Amirsaman, Marino Robert, Yan Xiaogang, Sun Saihong, Wang Hongying, Crawford J Douglas
Centre for Vision Research; Vision: Science to Applications Program; and Departments of Psychology, Biology, and Kinesiology and Health Sciences, York University, Toronto, Ontario, Canada.
Centre for Neuroscience Studies, Queen's University, Kingston, Ontario, CanadaCentre for Vision Research; Vision: Science to Applications Program; and Departments of Psychology, Biology, and Kinesiology and Health Sciences, York University, Toronto, Ontario, Canada.
J Vis. 2017 May 1;17(5):20. doi: 10.1167/17.5.20.
The relative contributions of egocentric versus allocentric cues on goal-directed behavior have been examined for reaches, but not saccades. Here, we used a cue conflict task to assess the effect of allocentric landmarks on gaze behavior. Two head-unrestrained macaques maintained central fixation while a target flashed in one of eight radial directions, set against a continuously present visual landmark (two horizontal/vertical lines spanning the visual field, intersecting at one of four oblique locations 11° from the target). After a 100-ms delay followed by a 100-ms mask, the landmark was displaced by 8° in one of eight radial directions. After a second delay (300-700 ms), the fixation point extinguished, signaling for a saccade toward the remembered target. When the landmark was stable, saccades showed a significant but small (mean 15%) pull toward the landmark intersection, and endpoint variability was significantly reduced. When the landmark was displaced, gaze endpoints shifted significantly, not toward the landmark, but partially (mean 25%) toward a virtual target displaced like the landmark. The landmark had a larger influence when it was closer to initial fixation, and when it shifted away from the target, especially in saccade direction. These findings suggest that internal representations of gaze targets are weighted between egocentric and allocentric cues, and this weighting is further modulated by specific spatial parameters.
对于伸手动作，已经研究了自我中心线索与空间中心线索对目标导向行为的相对贡献，但对于扫视动作尚未进行研究。在这里，我们使用了一个线索冲突任务来评估空间中心地标对注视行为的影响。两只头部不受约束的猕猴保持中央注视，同时一个目标在八个径向方向之一闪烁，背景是一个持续存在的视觉地标（两条横跨视野的水平/垂直线，在距目标11°的四个倾斜位置之一相交）。在100毫秒的延迟后接着是100毫秒的掩蔽，地标在八个径向方向之一上被移动8°。在第二次延迟（300 - 700毫秒）后，注视点熄灭，指示向记忆中的目标进行扫视。当地标稳定时，扫视显示出对地标交叉点有显著但较小（平均15%）的吸引，并且终点变异性显著降低。当地标被移动时，注视终点显著移动，不是朝着地标，而是部分（平均25%）朝着像地标一样移动的虚拟目标。当地标更靠近初始注视点时，以及当地标远离目标移动时，尤其是在扫视方向上，地标具有更大的影响。这些发现表明，注视目标的内部表征在自我中心线索和空间中心线索之间加权，并且这种加权进一步受到特定空间参数的调节。
