Leupin Viviana, Britz Juliane
Department of Psychology, University of Fribourg, University of Fribourg, Rue P.-A. Faucigny 2, Fribourg, CH-1700, Switzerland.
Brain Topogr. 2025 Aug 28;38(5):62. doi: 10.1007/s10548-025-01139-6.
Perceptual awareness of threshold or multi-stable stimuli varies with the pre-stimulus global state of the brain as indexed by EEG microstates. Similarly, awareness also varies with cyclic fluctuations of visceral signals across the cardiac and the respiratory cycle. It remains to be investigated whether the momentary state of the brain contributes to awareness jointly or independently of the bodily phase. We used an orientation discrimination task to determine to what degree the subjective awareness of a visual threshold stimulus varied with the pre-stimulus microstate, cardiac and respiratory phase and whether the brain and body exerted a joint or independent influence on fluctuations of subjective awareness. We compared the pre-stimulus EEG microstates preceding correct aware and unaware trials for the cardiac and respiratory phase. Our findings indicate that the canonical Microstate D was more prevalent in the unaware compared to the aware condition, and the canonical Microstate A accounted for more variance during inhalation compared to exhalation. The pre-stimulus activation of Microstate D, which is anticorrelated with attentional networks preceded trials in which the stimulus was not perceived. Inhalation was instead associated with Microstate A, suggesting increased arousal during this phase. However, we observed no interaction between the bodily phase and awareness, suggesting that the states of the brain and the body exert independent influence on perceptual awareness at the discrimination threshold.
对阈值或多稳态刺激的感知觉意识会随着脑电图微状态所指示的刺激前大脑全局状态而变化。同样，意识也会随着心脏和呼吸周期中内脏信号的周期性波动而变化。大脑的瞬间状态对意识的影响是与身体阶段共同作用还是独立于身体阶段，仍有待研究。我们使用了一种方向辨别任务来确定视觉阈值刺激的主观意识在多大程度上随刺激前的微状态、心脏和呼吸阶段而变化，以及大脑和身体对主观意识波动是产生共同影响还是独立影响。我们比较了在心脏和呼吸阶段正确的有意识和无意识试验之前的刺激前脑电图微状态。我们的研究结果表明，与有意识状态相比，典型的微状态D在无意识状态中更普遍，并且与呼气相比，典型的微状态A在吸气期间解释了更多的方差。在未察觉到刺激的试验之前，与注意力网络呈反相关的微状态D的刺激前激活出现。相反，吸气与微状态A相关，表明在此阶段唤醒增加。然而，我们没有观察到身体阶段和意识之间的相互作用，这表明大脑和身体状态对辨别阈值处的感知觉意识产生独立影响。
