Converging intracranial markers of conscious access.
Converging intracranial markers of conscious access.
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DOI：
10.1371/journal.pbio.1000061
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发表时间：
2009-03-17
期刊：
影响因子：
9.8
通讯作者：
Naccache L
中科院分区：
文献类型：
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作者：
Gaillard R;Dehaene S;Adam C;Clémenceau S;Hasboun D;Baulac M;Cohen L;Naccache L
我们比较了有意识和无意识的处理短暂闪现的话，使用视觉掩蔽程序，同时记录颅内脑电图（iEEG）在10例患者。在多个皮层区域观察到对掩蔽词的无意识处理，大多数在早期时间窗内（<300 ms），伴随着诱导的γ-波段活动，但没有连贯的长距离神经活动，表明前馈波迅速消散。相比之下，有意识地处理未掩蔽的单词的特点是四个不同的神经生理标记的收敛：持续的电压变化，特别是在前额叶皮层，在伽马波段的频谱功率大幅增加，在β范围内的长距离相位同步的增加，并增加在远程格兰杰因果关系。我们认为，所有这些措施提供了不同的窗口到相同的分布式状态的意识处理。这些结果对当前关于有意识访问的神经相关性的理论讨论有直接影响。有意识地感知视觉刺激的神经信号是什么？为了解决这个问题，我们直接记录了人类受试者（因医疗原因接受神经手术）大脑的神经活动。这种罕见的机会提供了更大的空间和时间分辨率比以前使用的非侵入性方法来探测意识的神经基础。我们比较了神经活动伴随着有意识和无意识的处理的话，通过使用视觉掩蔽程序，使我们能够操纵有意识的可见性，简要掩蔽的话。无意识的文字处理引起了多个皮层区域的短暂活动，包括顶叶和视觉区域。与此形成鲜明对比的是，只有有意识地感知到的单词才伴随着在各种各样的皮层部位的长期影响（>200 ms），特别是前额叶。这种持续的神经活动模式的特征是远距离区域之间的一致性的特定增加，这表明有意识的感知在大脑皮层中广泛传播。人类有意识感知词语的神经特征在颅内电生理记录中是可读的，这提供了相对高的空间和时间分辨率的神经活动测量。
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. What is the neural signature of the conscious perception of a visual stimulus? To address this question, we recorded neural activity directly from the brains of human subjects (who were undergoing neural surgery for medical reasons). This rare opportunity afforded greater spatial and temporal resolution than noninvasive methods used previously to probe the neural basis of consciousness. We compared neural activity concomitant with conscious and nonconscious processing of words by using a visual masking procedure that allowed us to manipulate the conscious visibility of briefly masked words. Nonconscious processing of words elicited short-lasting activity across multiple cortical areas, including parietal and visual areas. In sharp contrast, only consciously perceived words were accompanied by long-lasting effects (>200 ms) across a great variety of cortical sites, with a special involvement of the prefrontal lobes. This sustained pattern of neural activity was characterized by a specific increase of coherence between distant areas, suggesting conscious perception is broadcasted widely across the cortex. A neural signature of the conscious perception of words by humans is readable in intracranial electrophysiological recordings, which afford relatively high spatial- and temporal-resolution measurements of neural activity.
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DOI：
10.1073/pnas.0308538101
发表时间：
2004-06-29
影响因子：
11.1
作者：
Brovelli, A;Ding, MZ;Bressler, SL
通讯作者：
Bressler, SL
影响因子：
3.2
作者：
Fahrenfort, J. J.;Scholte, H. S.;Lamme, V. A. F.
通讯作者：
Lamme, V. A. F.
DOI：
10.1073/pnas.95.24.14529
发表时间：
1998-11-24
影响因子：
11.1
作者：
Dehaene, S;Kerszberg, M;Changeux, JP
通讯作者：
Changeux, JP
DOI：
10.1073/pnas.86.5.1698
发表时间：
1989-03-01
影响因子：
11.1
作者：
GRAY, CM;SINGER, W
通讯作者：
SINGER, W
影响因子：
9.8
作者：
通讯作者：
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