Herde Laura, Rossi Valentina, Pourtois Gilles, Rauss Karsten
a Institute of Medical Psychology and Behavioral Neurobiology , University of Tübingen , Tübingen , Germany.
b Cognitive & Affective Psychophysiology Laboratory, Department of Experimental Clinical and Health Psychology , Ghent University , Ghent , Belgium.
Cogn Neurosci. 2018 Jan-Apr;9(1-2):38-55. doi: 10.1080/17588928.2017.1338250. Epub 2017 Jun 28.
Reports of modulations of early visual processing suggest that retinotopic visual cortex may actively predict upcoming stimuli. We tested this idea by showing healthy human participants images of human faces at fixation, with different emotional expressions predicting stimuli in either the upper or the lower visual field. On infrequent test trials, emotional faces were followed by combined stimulation of upper and lower visual fields, thus violating previously established associations. Results showed no effects of such violations at the level of the retinotopic C1 of the visual evoked potential over the full sample. However, when separating participants who became aware of these associations from those who did not, we observed significant group differences during extrastriate processing of emotional faces, with inverse solution results indicating stronger activity in unaware subjects throughout the ventral visual stream. Moreover, within-group comparisons showed that the same peripheral stimuli elicited differential activity patterns during the C1 interval, depending on which stimulus elements were predictable. This effect was selectively observed in manipulation-aware subjects. Our results provide preliminary evidence for the notion that early visual processing stages implement predictions of upcoming events. They also point to conscious awareness as a moderator of predictive coding.
早期视觉处理调制的报告表明，视网膜拓扑视觉皮层可能会积极预测即将到来的刺激。我们通过向健康人类参与者展示固定状态下的人脸图像来测试这一想法，不同的情绪表情预测上半视野或下半视野中的刺激。在不频繁的测试试验中，情绪面孔之后会同时刺激上半视野和下半视野，从而违反了先前建立的关联。结果显示，在整个样本中，这种违反情况在视觉诱发电位的视网膜拓扑C1水平上没有影响。然而，当将意识到这些关联的参与者与未意识到的参与者分开时，我们在情绪面孔的纹外处理过程中观察到了显著的组间差异，逆解结果表明，在整个腹侧视觉流中，未意识到的受试者活动更强。此外，组内比较表明，相同的外周刺激在C1间隔期间会引发不同的活动模式，这取决于哪些刺激元素是可预测的。这种效应在意识到操作的受试者中被选择性地观察到。我们的结果为早期视觉处理阶段对即将发生的事件进行预测这一观点提供了初步证据。它们还指出意识是预测编码的一个调节因素。
