Distinguishing the Neural Correlates of Perceptual Awareness and Postperceptual Processing
Distinguishing the Neural Correlates of Perceptual Awareness and Postperceptual Processing
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DOI：
10.1523/jneurosci.0120-20.2020
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发表时间：
2020-06-17
影响因子：
5.3
通讯作者：
Pitts, Michael
中科院分区：
文献类型：
--
作者：
Cohen, Michael A.;Ortego, Kevin;Pitts, Michael
为了确定知觉意识的神经相关性，研究人员经常比较观察者是否意识到刺激的条件之间的神经激活差异。虽然直观，但这种方法通常包含一个关键的限制：为了将大脑活动与感知意识联系起来，观察者传统上会报告他们感知体验的内容。然而，依赖于观察者的报告是有问题的，因为很难知道被测量的神经反应是与有意识的感知相关联还是与报告任务中涉及的感知后过程相关联（例如，工作记忆，决策）。为了解决这个问题，我们结合了一个标准的视觉掩蔽范式与最近开发的“无报告”范式在男性/女性人类参与者。在视觉掩蔽范式中，观察者看到的是可见或不可见的动物和物体的图像，这取决于它们与面具的接近程度。同时，在一半的试验中，观察者报告了他们的知觉经验的内容（即，报告条件），而在另一半试验中，他们避免报告他们的经历（即，无报告条件）。我们使用脑电图来研究如何通过测量P3 b事件相关电位，有意识处理的建议规范的“签名”之一，能见度与报告相互作用。总的来说，我们在报告条件下发现了一个强大的P3 b，但在无报告条件下没有P3 b。这一发现表明，P3 b本身不是有意识处理的神经信号，并强调了仔细区分知觉意识和知觉后处理的神经相关物的重要性。
To identify the neural correlates of perceptual awareness, researchers often compare the differences in neural activation between conditions in which an observer is or is not aware of a stimulus. While intuitive, this approach often contains a critical limitation: to link brain activity with perceptual awareness, observers traditionally report the contents of their perceptual experience. However, relying on observers' reports is problematic because it is difficult to know whether the neural responses being measured are associated with conscious perception or with postperceptual processes involved in the reporting task (e.g., working memory, decision-making). To address this issue, we combined a standard visual masking paradigm with a recently developed "no-report" paradigm in male/female human participants. In the visual masking paradigm, observers saw images of animals and objects that were visible or invisible, depending on their proximity to masks. Meanwhile, on half of the trials, observers reported the contents of their perceptual experience (i.e., report condition), while on the other half of trials they refrained from reporting about their experiences (i.e., no-report condition). We used electroencephalography to examine how visibility interacts with reporting by measuring the P3b event-related potential, one of the proposed canonical "signatures" of conscious processing. Overall, we found a robust P3b in the report condition, but no P3b whatsoever in the no-report condition. This finding suggests that the P3b itself is not a neural signature of conscious processing and highlights the importance of carefully distinguishing the neural correlates of perceptual awareness from postperceptual processing.