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）是一种当观察者双眼以分视方式接收两幅不同图像时，知觉会在二者间自发切换的现象。阐明介导这类知觉随机波动的皮层网络，有助于我们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分视视觉刺激过程中的同步脑电图-功能磁共振成像（EEG-fMRI）数据。实验中为双眼各自呈现的图像标记了不同的时间频率，以便从脑电图数据中提取眼特异性稳态视觉诱发电位（SSVEP）信号，从而能够直接对比与双眼竞争相关的功能磁共振血氧水平依赖（BOLD）活动变化。此外，本研究还设置了平滑回放条件，模拟双眼竞争过程中发生的知觉转换过程，作为对照刺激范式。本研究采用了一种基于SSVEP的新型功能磁共振分析方法，从电生理与行为两个维度刻画竞争相关BOLD活动的时间动态特征。具体而言，我们分析了与两个竞争的、经频率标记的SSVEP信号峰值及过零点直接相关的竞争期间BOLD活动，并将其与受试者报告的知觉转换相关的BOLD活动进行对比。研究结果显示，右侧偏侧化额顶网络（fronto-parietal network）在双稳态刺激处理过程中发挥关键作用：相较于对照回放条件，右侧顶上/下小叶的BOLD活动在整个双眼竞争过程中均显著升高，尤其在知觉转换阶段更为突出。基于SSVEP的分析进一步表明，相较于SSVEP过零点，知觉转换阶段的后中部扣带回皮层BOLD抑制效应显著增强。综上，本研究揭示了早期视觉皮层、右侧后顶叶皮层与中部扣带回皮层之间的精细相互作用，该机制介导了双眼竞争相关的自发知觉转换，对未来开展知觉与意识的多模态成像研究具有重要的科学启示意义。