Abstract An increasing amount of studies suggest that brain dynamics measured with resting-state functional magnetic resonance imaging (fMRI) are related to the state of consciousness. However, the challenge of investigating neuronal correlates of consciousness is the confounding interference between (recovery of) consciousness and behavioral responsiveness. To address this issue, and validate the interpretation of prior work linking brain dynamics and consciousness, we performed a longitudinal fMRI study in patients recovering from coma. Patients were assessed twice, 6 months apart, and assigned to one of two groups. One group included patients who were unconscious at the first assessment but regained consciousness and improved behavioral responsiveness by the second assessment. The other group included patients who were already conscious and improved only behavioral responsiveness. While the two groups were matched in terms of the average increase in behavioral responsiveness, only one group experienced a categorical change in their state of consciousness allowing us to partially dissociate consciousness and behavioral responsiveness. We find the variance in network metrics to be systematically different across states of consciousness, both within and across groups. Specifically, at the first assessment, conscious patients exhibited significantly greater variance in network metrics than unconscious patients, a difference that disappeared once all patients had recovered consciousness. Furthermore, we find a significant increase in dynamics for patients who regained consciousness over time, but not for patients who only improved responsiveness. These findings suggest that changes in brain dynamics are indeed linked to the state of consciousness and not just to a general level of behavioral responsiveness.

中文翻译：

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对人脑中网络动力学与意识状态之间关联的系统研究

摘要越来越多的研究表明，静息态功能磁共振成像（fMRI）测量的大脑动力学与意识状态有关。然而，研究意识的神经元相关性的挑战是意识（行为的恢复）与行为反应之间的混杂干扰。为了解决这个问题，并验证将大脑动力学与意识联系起来的先前工作的解释，我们对从昏迷中康复的患者进行了纵向功能磁共振成像研究。对患者进行了两次评估，相隔6个月，分为两组。一组患者包括在第一次评估中失去知觉但在第二次评估中恢复了意识并改善了行为反应的患者。另一组包括已经清醒并且仅改善行为反应性的患者。两组在行为反应能力的平均增加方面是匹配的，但只有一组经历了意识状态的绝对变化，这使我们能够部分分离意识和行为反应能力。我们发现，网络度量的方差在群体内部和群体之间的意识状态之间系统地不同。具体来说，在第一次评估中，有意识的患者在网络指标方面的表现要比无意识的患者大得多，一旦所有患者都恢复了意识，这种差异就会消失。此外，我们发现随着时间的流逝，重新获得意识的患者的动态变化显着增加，但不适用于仅改善响应能力的患者。这些发现表明，大脑动力学的变化确实与意识状态有关，而不仅与行为反应的一般水平有关。