Kroell Lisa M, Rolfs Martin
Department of Psychology, Humboldt-Universität zu Berlin, Berlin, Germany.
Berlin School of Mind and Brain, Humboldt-Universität zu Berlin, Berlin, Germany.
Elife. 2025 Jul 10;12:RP91236. doi: 10.7554/eLife.91236.
We previously demonstrated that during the preparation of a saccadic eye movement, human observers anticipate defining features of the eye movement target in pre-saccadic foveal vision (Kroell and Rolfs, 2022). In this Research Advance, we show that the conspicuity of feature information at the saccade target location influences the magnitude and time course of foveal enhancement. Observers prepared a saccade to a peripheral orientation signal (the target) while monitoring the appearance of another orientation signal (the probe) in their pre-saccadic center of gaze. The foveal probe appeared in 50% of trials and either had the same orientation as the target (congruent) or a different orientation (incongruent). Crucially, we manipulated the opacity of the target against the 1/f noise background in four logarithmic steps (25-90%). An increase in opacity translated to an increase in luminance contrast and signal-to-noise ratio of orientation information within the target region. Foveal enhancement defined as the difference between hit rates to target-congruent and target-incongruent foveal probes increased with target opacity. Moreover, the time course of foveal enhancement showed an oscillatory pattern that was particularly pronounced at high target opacities. Reverse correlations furthermore suggest that at higher target opacities, false alarms were increasingly triggered by signal, i.e., by incidental orientation information in the foveal noise. Beyond providing new mechanistic insights, these findings are relevant for researchers planning to adapt our paradigm to study related questions. Presenting the saccade target at a high signal-to-noise ratio appears beneficial, as foveal congruency effects, especially when time-resolved, are most robustly detectable.
我们之前证明,在扫视眼动准备过程中,人类观察者会在扫视前的中央凹视觉中预测眼动目标的定义特征(Kroell和Rolfs,2022年)。在这项研究进展中,我们表明扫视目标位置的特征信息显著性会影响中央凹增强的幅度和时间进程。观察者准备向周边的方向信号(目标)进行扫视,同时监测扫视前注视中心中另一个方向信号(探测信号)的出现。中央凹探测信号在50%的试验中出现,其方向与目标相同(一致)或不同(不一致)。至关重要的是,我们在四个对数步长(25%-90%)中操纵目标在1/f噪声背景下的不透明度。不透明度的增加转化为目标区域内方向信息的亮度对比度和信噪比的增加。定义为对目标一致和目标不一致的中央凹探测信号的命中率之差的中央凹增强随着目标不透明度的增加而增加。此外,中央凹增强的时间进程显示出一种振荡模式,在高目标不透明度时尤为明显。反向相关性还表明,在较高的目标不透明度下,误报越来越多地由信号触发,即由中央凹噪声中的偶然方向信息触发。这些发现不仅提供了新的机制性见解,对计划采用我们的范式来研究相关问题的研究人员也具有重要意义。以高信噪比呈现扫视目标似乎是有益的,因为中央凹一致性效应,尤其是在进行时间分辨时,最容易被检测到。