Jan Drewes¹, Mingjie Gao², Weina Zhu²; ¹Institute of Brain and Psychological Sciences, Sichuan Normal University, Chengdu, China, ²School of Information Science, Yunnan University, Kunming, China

What happens in our brain when a perceived target enters our visual awareness, and what factors regulate this process? For years, b-CFS has been an effective tool for studying conscious awareness by using high-contrast dynamic masks in one eye to suppress awareness of a static target stimulus with gradually increasing contrast in the other eye for relative long time. Participants' response times serve as a behavioral indicator of conscious awareness. However, the brain dynamics underlying this conscious process remain a “black box.” In this study, we address this gap by combining EEG/SSVEP frequency tagging and sensory entrainment in a b-CFS paradigm to track and modulate the process of conscious perception. Sensory entrainment was achieved by presenting beep sounds at the same frequency as the target or mask stimuli. Through time-frequency analysis, we found that the power and time course of the target and mask frequencies was modulated by cross-modal sensory entrainment. Sensory entrainment enhanced the target frequency energy in the target-entrainment condition and the mask frequency energy in the mask-entrainment condition, relative to the no-entrainment condition. Regarding the time course, the mask frequency initially dominated but decreased over time, while the target frequency energy began to increase after a certain point, with a crossover occurring eventually. Notably, such crossover time occurred earlier in the target-entrainment condition compared to both no-entrainment and mask-entrainment conditions. These findings suggest that visual awareness can be tracked using CFS-Tagging, and its progression can be modulated through frequency energy.

Acknowledgements: WZ was supported by the National Natural Science Foundation of China (61263042, 61563056)