Department of Psychiatry and Psychotherapy, Multisensory Integration Lab, Charité Universitätsmedizin Berlin, Germany; Biological Psychology Christian-Albrechts-University Kiel, Kiel, Germany.
Department of Psychiatry and Psychotherapy, Multisensory Integration Lab, Charité Universitätsmedizin Berlin, Germany.
Neuroimage. 2022 Feb 1;246:118787. doi: 10.1016/j.neuroimage.2021.118787. Epub 2021 Dec 7.
In the flash-lag illusion (FLI), the position of a flash presented ahead of a moving bar is mislocalized, so the flash appears to lag the bar. Currently, it is not clear whether this effect is due to early perceptual-related neural processes such as motion extrapolation or reentrant processing, or due to later feedback processing relating to postdiction, i.e., retroactively altered perception. We presented 17 participants with the FLI paradigm while recording EEG. A central flash occurred either 51 ms ("early") or 16 ms ("late") before the bar moving from left to right reached the screen center. Participants judged whether the flash appeared to the right ("no flash lag illusion") or to the left ("flash-lag illusion") of the bar. Using single-trial linear modeling, we examined the influence of timing ("early" vs. "late") and perception ("illusion" vs. "no illusion") on flash-evoked brain responses and estimated the cortical sources underlying the FLI. An earlier frontal and occipital component (200-276 ms) differentiated time-locked early vs. late stimulus presentation, indicating that early evoked brain responses reflect feature encoding in the FLI. Perception of the FLI was associated with a late window (368-452 ms) in the ERP, with larger deflections for illusion than no illusion trials, localized to the left inferior occipital gyrus. This suggests a postdiction-related reconstruction of ambiguous sensory stimulation involving late processes in the occipito-temporal cortex, previously associated with temporal integration phenomena. Our findings indicate that perception of the FLI relies on an interplay between ongoing stimulus encoding of the moving bar and feedback processing of the flash, which takes place at later integration stages.
在闪光滞后错觉（FLI）中，先于移动棒呈现的闪光位置会发生错位，因此闪光看起来滞后于棒。目前，尚不清楚这种效应是由于早期与运动外推或再传入处理相关的知觉相关神经过程引起的，还是由于与后预测相关的后期反馈处理引起的，即回溯性改变知觉。我们在记录 EEG 的同时向 17 名参与者展示了 FLI 范式。中央闪光要么在棒从左向右移动到屏幕中心之前 51 毫秒（“早期”），要么在 16 毫秒（“晚期”）之前出现。参与者判断闪光是否出现在棒的右侧（“无闪光滞后错觉”）或左侧（“闪光滞后错觉”）。使用单试线性建模，我们检查了时间（“早期”与“晚期”）和知觉（“错觉”与“无错觉”）对闪光诱发脑反应的影响，并估计了 FLI 的皮质源。一个更早的额部和枕部成分（200-276 毫秒）区分了时间锁定的早期与晚期刺激呈现，表明早期诱发的脑反应反映了 FLI 中的特征编码。错觉的感知与 ERP 中的晚期窗口（368-452 毫秒）相关，错觉试验比无错觉试验的偏转更大，定位于左侧下枕叶。这表明与预测相关的对模糊感觉刺激的重建涉及枕颞皮质中的晚期过程，这些过程先前与时间整合现象有关。我们的研究结果表明，对 FLI 的感知依赖于移动棒的持续刺激编码和闪光的反馈处理之间的相互作用，这种处理发生在后期整合阶段。
