Gaillard Raphaël, Dehaene Stanislas, Adam Claude, Clémenceau Stéphane, Hasboun Dominique, Baulac Michel, Cohen Laurent, Naccache Lionel
INSERM, Cognitive Neuro-Imaging Unit, Institut Fédé ratif de Recherche (IFR) 49, Gif sur Yvette, France.
PLoS Biol. 2009 Mar 17;7(3):e61. doi: 10.1371/journal.pbio.1000061.
We compared conscious and nonconscious processing of briefly flashed words using a visual masking procedure while recording intracranial electroencephalogram (iEEG) in ten patients. Nonconscious processing of masked words was observed in multiple cortical areas, mostly within an early time window (<300 ms), accompanied by induced gamma-band activity, but without coherent long-distance neural activity, suggesting a quickly dissipating feedforward wave. In contrast, conscious processing of unmasked words was characterized by the convergence of four distinct neurophysiological markers: sustained voltage changes, particularly in prefrontal cortex, large increases in spectral power in the gamma band, increases in long-distance phase synchrony in the beta range, and increases in long-range Granger causality. We argue that all of those measures provide distinct windows into the same distributed state of conscious processing. These results have a direct impact on current theoretical discussions concerning the neural correlates of conscious access.
我们在10名患者记录颅内脑电图（iEEG）的同时，使用视觉掩蔽程序比较了对短暂闪现单词的有意识和无意识加工。在多个皮质区域观察到对掩蔽单词的无意识加工，主要在早期时间窗口（<300毫秒）内，伴有诱发的伽马波段活动，但没有连贯的长距离神经活动，这表明存在一个迅速消散的前馈波。相比之下，对未掩蔽单词的有意识加工具有四种不同神经生理标记物的汇聚特征：持续的电压变化，特别是在前额叶皮质；伽马波段频谱功率大幅增加；β范围内长距离相位同步增加；以及长程格兰杰因果关系增加。我们认为，所有这些测量方法都为有意识加工的同一分布式状态提供了不同的观察窗口。这些结果对当前有关意识通达神经关联的理论讨论有直接影响。
