Cortical response tracking the conscious experience of threshold duration visual stimuli indicates visual perception is all or none
Cortical response tracking the conscious experience of threshold duration visual stimuli indicates visual perception is all or none
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DOI：
10.1073/pnas.1302229110
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发表时间：
2013-04-02
影响因子：
11.1
通讯作者：
Llinas, Rodolfo R.
中科院分区：
文献类型：
--
作者：
Sekar, Krithiga;Findley, William M.;Llinas, Rodolfo R.
在感知阈值，一些刺激可用于有意识的访问，而其他刺激则不可用。这种阈值输入是研究将有意识的意识与无意识的刺激处理分开的事件的有用工具。在这里，观看未掩蔽的阈值持续时间图像与记录脑磁图相结合，以量化感知状态之间的差异，从没有意识到模糊到强大的感知。使用四项选择量表来评估意识：“没有看到”（没有意识）、“无法识别”（没有识别的意识）、“不确定”（低确定性识别的意识）和“确定”（高确定性识别的意识）。刺激诱发的神经磁信号进行分组，根据行为反应的选择。三个主要的皮质反应引起。最早的反应，刺激呈现后100毫秒左右达到峰值，与刺激感知没有显着相关性。迟发反应（类似于290毫秒）表现出适度的相关性与刺激意识，但不能充分区分有意识的访问，其缺席。相比之下，一个中间的反应峰值在240毫秒相似的试验中观察到的刺激有意识地检测。该信号在报告意识的所有条件下都是相似的，这与有意识的视觉通路界限相对明显的假设是一致的。
At perceptual threshold, some stimuli are available for conscious access where as others are not. Such threshold inputs are useful tools for investigating the events that separate conscious awareness from unconscious stimulus processing. Here, viewing unmasked, thresh-old-duration images was combined with recording magnetoencephalography to quantify differences among perceptual states, ranging from no awareness to ambiguity to robust perception. A four-choice scale was used to assess awareness: "didn't see" (no awareness), "couldn't identify" (awareness without identification), "unsure" (awareness with low certainty identification), and "sure" (awareness with high certainty identification). Stimulus-evoked neuromagnetic signals were grouped according to behavioral response choices. Three main cortical responses were elicited. The earliest response, peaking at similar to 100 ms after stimulus presentation, showed no significant correlation with stimulus perception. A late response (similar to 290 ms) showed moderate correlation with stimulus awareness but could not adequately differentiate conscious access from its absence. By contrast, an intermediate response peaking at similar to 240 ms was observed only for trials in which stimuli were consciously detected. That this signal was similar for all conditions in which awareness was reported is consistent with the hypothesis that conscious visual access is relatively sharply demarcated.