Baria Alexis T, Maniscalco Brian, He Biyu J
National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland, United States of America.
Neuroscience Institute, New York University Langone Medical Center, New York, NY, United States of America.
PLoS Comput Biol. 2017 Nov 27;13(11):e1005806. doi: 10.1371/journal.pcbi.1005806. eCollection 2017 Nov.
Recent research has identified late-latency, long-lasting neural activity as a robust correlate of conscious perception. Yet, the dynamical nature of this activity is poorly understood, and the mechanisms governing its presence or absence and the associated conscious perception remain elusive. We applied dynamic-pattern analysis to whole-brain slow (< 5 Hz) cortical dynamics recorded by magnetoencephalography (MEG) in human subjects performing a threshold-level visual perception task. Up to 1 second before stimulus onset, brain activity pattern across widespread cortices significantly predicted whether a threshold-level visual stimulus was later consciously perceived. This initial state of brain activity interacts nonlinearly with stimulus input to shape the evolving cortical activity trajectory, with seen and unseen trials following well separated trajectories. We observed that cortical activity trajectories during conscious perception are fast evolving and robust to small variations in the initial state. In addition, spontaneous brain activity pattern prior to stimulus onset also influences unconscious perceptual making in unseen trials. Together, these results suggest that brain dynamics underlying conscious visual perception belongs to the class of initial-state-dependent, robust, transient neural dynamics.
最近的研究已将晚期潜伏期、持久的神经活动确定为有意识感知的一种可靠关联指标。然而，这种活动的动态本质却鲜为人知，且控制其存在与否以及相关有意识感知的机制仍然难以捉摸。我们将动态模式分析应用于人类受试者在执行阈值水平视觉感知任务时通过脑磁图（MEG）记录的全脑慢（<5赫兹）皮层动态。在刺激开始前长达1秒的时间里，广泛皮层的脑活动模式能显著预测阈值水平的视觉刺激随后是否会被有意识地感知到。这种脑活动的初始状态与刺激输入进行非线性相互作用，以塑造不断演变的皮层活动轨迹，其中被感知和未被感知的试验遵循明显分离的轨迹。我们观察到，有意识感知期间的皮层活动轨迹快速演变，并且对初始状态的微小变化具有鲁棒性。此外，刺激开始前的自发脑活动模式也会影响未被感知试验中的无意识感知决策。总之，这些结果表明，有意识视觉感知背后的脑动力学属于初始状态依赖、鲁棒、瞬态神经动力学类别。
