Department of Psychology, University of Münster, Münster, Germany.
Otto-Creutzfeldt-Centre for Cognitive and Behavioural Neuroscience, University of Münster, Münster, Germany.
PLoS One. 2021 Jul 26;16(7):e0255116. doi: 10.1371/journal.pone.0255116. eCollection 2021.
Although statistical regularities in the environment often go explicitly unnoticed, traces of implicit learning are evident in our neural activity. Recent perspectives have offered evidence that both pre-stimulus oscillations and peri-stimulus event-related potentials are reliable biomarkers of implicit expectations arising from statistical learning. What remains ambiguous, however, is the origination and development of these implicit expectations. To address this lack of knowledge and determine the temporal constraints of expectation formation, pre-stimulus increases in alpha/beta power were investigated alongside a reduction in the N170 and a suppression in peri-/post-stimulus gamma power. Electroencephalography was acquired from naive participants who engaged in a gender classification task. Participants were uninformed, that eight face images were sorted into four reoccurring pairs which were pseudorandomly hidden amongst randomly occurring face images. We found a reduced N170 for statistically expected images at left parietal and temporo-parietal electrodes. Furthermore, enhanced gamma power following the presentation of random images emphasized the bottom-up processing of these arbitrary occurrences. In contrast, enhanced alpha/beta power was evident pre-stimulus for expected relative to random faces. A particularly interesting finding was the early onset of alpha/beta power enhancement which peaked immediately after the depiction of the predictive face. Hence, our findings propose an approximate timeframe throughout which consistent traces of enhanced alpha/beta power illustrate the early prioritisation of top-down processes to facilitate the development of implicitly cued face-related expectations.
虽然环境中的统计规律通常被人们明确忽视，但在我们的神经活动中，内隐学习的痕迹是明显的。最近的观点提供了证据，表明前刺激振荡和刺激相关事件电位都是统计学习产生的内隐期望的可靠生物标志物。然而，这些内隐期望的起源和发展仍然不清楚。为了解决这方面的知识空白，并确定期望形成的时间限制，研究人员调查了 alpha/beta 功率的预刺激增加，同时伴随着 N170 的减少和 peri-/post-stimulus gamma 功率的抑制。研究人员从参与性别分类任务的新手参与者那里获取了脑电图。参与者不知道，有 8 张脸的图像被分成了 4 对经常出现的图像，这些图像是随机隐藏在随机出现的脸图像中的。研究人员发现，在左顶叶和颞顶叶电极上，统计上预期的图像的 N170 减少了。此外，在呈现随机图像后，伽马功率增强强调了这些任意事件的自下而上的处理。相比之下，对于预期的面孔，相对于随机面孔，alpha/beta 功率在刺激前增强明显。一个特别有趣的发现是，alpha/beta 功率增强的早期出现，其峰值出现在有预测性的脸出现之后。因此，我们的研究结果提出了一个大致的时间框架，在这个时间框架内，持续的 alpha/beta 功率增强表明了自上而下的过程的早期优先化，以促进隐含的与面孔相关的期望的发展。
