Data from: Deactivation in the posterior mid-cingulate cortex reflects perceptual transitions during binocular rivalry: evidence from simultaneous EEG-fMRI

Binocular rivalry is a phenomenon in which perception spontaneously shifts between two different images that are dichoptically presented to the viewer. By elucidating the cortical networks responsible for these stochastic fluctuations in perception, we can potentially learn much about the neural correlates of visual awareness. We obtained concurrent EEG-fMRI data for a group of 20 healthy human subjects during the continuous presentation of dichoptic visual stimuli. The two eyes’ images were tagged with different temporal frequencies so that eye specific steady-state visual evoked potential (SSVEP) signals could be extracted from the EEG data for direct comparison with changes in fMRI BOLD activity associated with binocular rivalry. We additionally included a smooth replay condition that emulated the perceptual transitions experienced during binocular rivalry as a control stimulus. We evaluated a novel SSVEP-informed fMRI analysis in this study in order to delineate the temporal dynamics of rivalry-related BOLD activity from both an electrophysiological and behavioral perspective. In this manner, we assessed BOLD activity during rivalry that was directly correlated with peaks and crosses of the two rivaling, frequency-tagged SSVEP signals, for comparison with BOLD activity associated with subject reported perceptual transitions. Our findings point to a critical role of a right lateralized fronto-parietal network in the processing of bistable stimuli, given that BOLD activity in the right superior/inferior parietal lobules was significantly elevated throughout binocular rivalry and in particular during perceptual transitions, compared with the replay condition. Based on the SSVEP-informed analysis, rivalry was further associated with significantly enhanced BOLD suppression in the posterior mid-cingulate cortex during perceptual transitions, compared with SSVEP crosses. Overall, this work points to a careful interplay between early visual areas, the right posterior parietal cortex and the mid-cingulate cortex in mediating the spontaneous perceptual changes associated with binocular rivalry and has significant implications for future multimodal imaging studies of perception and awareness.双眼竞争（Binocular rivalry）是一种知觉会在以双眼分视方式呈献给被试的两种不同图像之间自发切换的现象。通过阐明介导这类知觉随机波动的皮层网络，我们能够深入解析视觉觉知的神经关联。本研究招募了20名健康人类被试，收集了他们在持续接收双眼分视视觉刺激时的同步脑电-功能磁共振成像（electroencephalogram-functional magnetic resonance imaging, EEG-fMRI）数据。将双眼接收的图像标记为不同的时间频率，以便从脑电数据中提取眼特异性稳态视觉诱发电位（steady-state visual evoked potential, SSVEP）信号，进而直接对比与双眼竞争相关的fMRI血氧水平依赖（blood oxygen level dependent, BOLD）活动变化。本研究还设置了平滑重放条件，该条件模拟了双眼竞争过程中出现的知觉切换事件，作为对照刺激。本研究采用了一种基于SSVEP的新型fMRI分析方法，旨在从电生理与行为两个维度阐明竞争相关BOLD活动的时间动态特征。据此，我们评估了双眼竞争期间与两个经频率标记的竞争性SSVEP信号的峰值及过零点直接相关的BOLD活动，以对比与被试报告的知觉切换相关的BOLD活动。研究结果表明，右侧偏侧化额顶网络在双稳态刺激加工中发挥关键作用：相较于平滑重放条件，右侧上/下顶叶的BOLD活动在整个双眼竞争过程中均显著升高，尤其在知觉切换阶段更为突出。基于SSVEP辅助的分析方法，相较于SSVEP信号过零点阶段，知觉切换阶段的双眼竞争还会引发后扣带回中部皮层出现显著增强的BOLD抑制效应。综上，本研究揭示了早期视觉皮层、右侧后顶叶皮层与扣带回中部皮层之间的精密协同作用，该协同作用介导了双眼竞争相关的自发性知觉变化，本研究结果对未来开展知觉与视觉觉知的多模态成像研究具有重要参考价值。