Allgemeine und Experimentelle Psychologie, Department Psychologie, Ludwig-Maximilians-Universität München, 80802 München, Germany;
Graduate School of Systemic Neurosciences, Department Biologie, Ludwig-Maximilians-Universität München, 82152 Planegg, Germany.
Proc Natl Acad Sci U S A. 2019 May 7;116(19):9665-9670. doi: 10.1073/pnas.1813465116. Epub 2019 Apr 19.
Both patients with eye movement disorders and healthy participants whose oculomotor range had been experimentally reduced have been reported to show attentional deficits at locations unreachable by their eyes. Whereas previous studies were mainly based on the evaluation of reaction times, we measured visual sensitivity before saccadic eye movements and during fixation at locations either within or beyond participants' oculomotor range. Participants rotated their heads to prevent them from performing large rightward saccades. In this posture, an attentional cue was presented inside or outside their oculomotor range. Participants either made a saccade to the cue or maintained fixation while they discriminated the orientation of a visual noise patch. In contrast to previous reports, we found that the cue attracted visual attention regardless of whether it was presented within or beyond participants' oculomotor range during both fixation and saccade preparation. Moreover, when participants aimed to look to a cue that they could not reach with their eyes, we observed no benefit at their actual saccade endpoint. This demonstrates that spatial attention is not coupled to the executed oculomotor program but instead can be deployed unrestrictedly also toward locations to which no saccade can be executed. Our results are compatible with the view that covert and overt attentional orienting are guided by feedback projections of visual and visuomotor neurons of the gaze control system, irrespective of oculomotor limitations.
已有研究报道,眼球运动障碍患者和其眼动范围经实验性缩小的健康参与者在其眼球无法到达的位置会表现出注意力缺陷。虽然之前的研究主要基于反应时间的评估,但我们在进行眼跳之前和在固定位置测量了视觉敏感度,这些固定位置在参与者的眼动范围之内或之外。参与者转动头部以防止他们进行向右的大眼球跳动。在这种姿势下,在参与者的眼动范围之内或之外呈现一个注意线索。参与者要么向线索进行眼球跳动,要么在固定位置时辨别视觉噪声补丁的方向。与之前的报告相反,我们发现,无论在固定位置还是在眼球跳动准备期间,注意线索都能吸引视觉注意,无论它是在参与者的眼动范围之内还是之外呈现。此外,当参与者试图看向他们的眼睛无法到达的线索时,在他们实际的眼球跳动终点并没有观察到优势。这表明,空间注意力不与执行的眼球运动程序耦合,而是可以不受限制地部署到无法进行眼球跳动的位置。我们的结果与这样一种观点一致,即隐蔽和显性的注意定向是由注视控制系统的视觉和运动神经元的反馈投射引导的,而与眼球运动限制无关。