Department of Neurobiology and Anatomy, Wake Forest School of Medicine, Winston-Salem, United States.
Elife. 2024 Nov 4;13:RP97883. doi: 10.7554/eLife.97883.
The neural mechanisms that willfully direct attention to specific locations in space are closely related to those for generating targeting eye movements (saccades). However, the degree to which the voluntary deployment of attention to a location necessarily activates a corresponding saccade plan remains unclear. One problem is that attention and saccades are both automatically driven by salient sensory events; another is that the underlying processes unfold within tens of milliseconds only. Here, we use an urgent task design to resolve the evolution of a visuomotor choice on a moment-by-moment basis while independently controlling the endogenous (goal-driven) and exogenous (salience-driven) contributions to performance. Human participants saw a peripheral cue and, depending on its color, either looked at it (prosaccade) or looked at a diametrically opposite, uninformative non-cue (antisaccade). By varying the luminance of the stimuli, the exogenous contributions could be cleanly dissociated from the endogenous process guiding the choice over time. According to the measured time courses, generating a correct antisaccade requires about 30 ms more processing time than generating a correct prosaccade based on the same perceptual signal. The results indicate that saccade plans elaborated during fixation are biased toward the location where attention is endogenously deployed, but the coupling is weak and can be willfully overridden very rapidly.
自愿将注意力指向特定空间位置的神经机制与产生目标眼动（扫视）的机制密切相关。然而，将注意力有意地部署到某个位置是否必然会激活相应的扫视计划，这一点仍不清楚。一个问题是，注意和扫视都是自动受显著感觉事件驱动的；另一个问题是，潜在的过程仅在几十毫秒内展开。在这里，我们使用紧急任务设计，在独立控制性能的内源性（目标驱动）和外源性（显著驱动）贡献的情况下，逐毫秒解析视觉运动选择的演变。人类参与者看到一个外围线索，根据其颜色，要么看向它（正扫视），要么看向一个对角线相对的、无信息的非线索（反扫视）。通过改变刺激的亮度，可以将外源性贡献与随时间引导选择的内源性过程干净地分离。根据测量的时间过程，与基于相同感知信号生成正确的正扫视相比，生成正确的反扫视需要大约 30 毫秒的额外处理时间。结果表明，在注视时制定的扫视计划偏向于注意力内源性部署的位置，但这种耦合很弱，可以非常迅速地被强制覆盖。
