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）是一种感知会在分别呈献给双眼的两种不同图像间自发切换的现象。通过阐明介导此类感知随机波动的皮层网络，我们有望深入解析视觉意识的神经关联机制。本研究采集了20名健康人类受试者在持续呈现双眼视觉刺激时的同步脑电图-功能磁共振成像（EEG-fMRI）数据。为实现从脑电图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，以直接对比与双眼竞争相关的血氧水平依赖（BOLD）活动变化，我们为双眼各自呈现的图像标记了不同的时间频率。此外，我们增设了平滑重播条件，用以模拟双眼竞争过程中出现的感知切换事件，作为对照刺激。本研究评估了一种基于稳态视觉诱发电位的功能磁共振成像分析方法，旨在从电生理与行为双视角刻画竞争相关血氧水平依赖活动的时间动态特征。通过该分析框架，我们分别定位了双眼竞争期间与两种经频率标记的竞争性稳态视觉诱发电位信号峰值及过零点直接相关的血氧水平依赖活动，并将其与受试者自我报告的感知切换对应的血氧水平依赖活动进行对比分析。研究结果显示，右侧偏侧化额顶网络在双稳态刺激处理过程中扮演关键角色：相较于平滑重播条件，右侧上/下顶叶的血氧水平依赖活动在整个双眼竞争阶段均显著升高，且在感知切换时段尤为突出。基于稳态视觉诱发电位引导的分析结果进一步表明，相较于稳态视觉诱发电位过零点条件，感知切换阶段后扣带回中部皮层的血氧水平依赖抑制效应显著增强。总体而言，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细协同交互，该机制介导了与双眼竞争相关的自发感知变化，为未来开展感知与意识领域的多模态成像研究提供了重要启示。