Madison Anna, Callahan-Flintoft Chloe, Thurman Steven M, Hoffing Russell A Cohen, Touryan Jonathan, Ries Anthony J
U.S. DEVCOM Army Research Laboratory, Humans in Complex Systems, Aberdeen Proving Ground, MD, USA.
Warfighter Effectiveness Research Center, Department of Behavioral Sciences & Leadership, 2354 Fairchild Drive, Suite 6, U.S. Air Force Academy, CO, 80840, USA.
Atten Percept Psychophys. 2025 Jan;87(1):261-283. doi: 10.3758/s13414-024-03002-5. Epub 2025 Jan 23.
Historically, electrophysiological correlates of scene processing have been studied with experiments using static stimuli presented for discrete timescales where participants maintain a fixed eye position. Gaps remain in generalizing these findings to real-world conditions where eye movements are made to select new visual information and where the environment remains stable but changes with our position and orientation in space, driving dynamic visual stimulation. Co-recording of eye movements and electroencephalography (EEG) is an approach to leverage fixations as time-locking events in the EEG recording under free-viewing conditions to create fixation-related potentials (FRPs), providing a neural snapshot in which to study visual processing under naturalistic conditions. The current experiment aimed to explore the influence of low-level image statistics-specifically, luminance and a metric of spatial frequency (slope of the amplitude spectrum)-on the early visual components evoked from fixation onsets in a free-viewing visual search and navigation task using a virtual environment. This research combines FRPs with an optimized approach to remove ocular artifacts and deconvolution modeling to correct for overlapping neural activity inherent in any free-viewing paradigm. The results suggest that early visual components-namely, the lambda response and N1-of the FRPs are sensitive to luminance and spatial frequency around fixation, separate from modulation due to underlying differences in eye-movement characteristics. Together, our results demonstrate the utility of studying the influence of image statistics on FRPs using a deconvolution modeling approach to control for overlapping neural activity and oculomotor covariates.
从历史上看，场景处理的电生理相关性研究一直采用在离散时间尺度上呈现静态刺激的实验，参与者需保持固定的眼球位置。将这些研究结果推广到现实世界的情况仍存在差距，在现实世界中，人们会进行眼球运动以选择新的视觉信息，环境保持稳定，但会随着我们在空间中的位置和方向而变化，从而产生动态视觉刺激。同时记录眼球运动和脑电图（EEG）是一种方法，可在自由观看条件下将注视作为EEG记录中的时间锁定事件，以创建与注视相关的电位（FRP），提供一个神经快照，用于研究自然条件下的视觉处理。当前的实验旨在探讨低水平图像统计信息，特别是亮度和空间频率指标（幅度谱斜率），对在使用虚拟环境的自由观看视觉搜索和导航任务中注视开始时诱发的早期视觉成分的影响。本研究将FRP与一种优化方法相结合，以去除眼部伪迹，并采用反卷积建模来校正任何自由观看范式中固有的重叠神经活动。结果表明，FRP的早期视觉成分，即λ反应和N1，对注视周围的亮度和空间频率敏感，这与因眼球运动特征的潜在差异而产生的调制无关。总之，我们的结果证明了使用反卷积建模方法研究图像统计对FRP的影响的实用性，该方法可控制重叠神经活动和眼动协变量。
