Recent neurophysiological studies have proposed distinct roles of β and γ oscillations in implementing top-down and bottom-up processes. The present study aims to test this hypothesis in the domain of speech perception. We examined β and γ oscillations elicited to a tone contrast in a passive oddball paradigm, and their relationships with discrimination sensitivity d' and RT from two groups of healthy adults who showed high and low discrimination sensitivity to the contrast. The low-sensitivity group showed a significant reduction in β, which was further related to d'. Individual differences in RT were related to different frequency bands in the two groups, with a RT-β correlation in the low-sensitivity group, and a RT-γ relation in the high-sensitivity group. Based on these findings, we suggest that β, implicated in top-down processing, reflects individual differences in phonological representations, and that γ, involved in bottom-up processing, reflects individual differences in acoustic encoding.

中文翻译：

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由语音感知中的 beta 和 gamma 振荡反映的自上而下和自下而上的机制：个体差异方法

最近的神经生理学研究提出了 β 和 γ 振荡在实现自上而下和自下而上的过程中的不同作用。本研究旨在在语音感知领域测试这一假设。我们检查了被动古怪范式中由音调对比引起的 β 和 γ 振荡，以及它们与来自两组对对比表现出高和低辨别敏感度的健康成年人的辨别敏感度 d' 和 RT 的关系。低敏组显示β显着降低，这进一步与d'有关。RT的个体差异与两组不同频段有关，低敏组为RT-β相关，高敏组为RT-γ相关。基于这些发现，我们建议涉及自上而下处理的 β，