Tu Chia-An, Parviainen Tiina, Hämäläinen Jarmo A, Hsu Yi-Fang
Department of Educational Psychology and Counselling, National Taiwan Normal University, Taipei, 106308, Taiwan.
Jyväskylä Centre for Interdisciplinary Brain Research, Department of Psychology, University of Jyväskylä, Jyväskylä, 40014, Finland.
Neuropsychologia. 2025 Jan 29;207:109058. doi: 10.1016/j.neuropsychologia.2024.109058. Epub 2024 Nov 28.
Alpha oscillations are proposed to serve the function of inhibition to protect items in working memory from intruding information. In a modified Sternberg paradigm, alpha power was initially found to increase at the anticipation of strong compared to weak distractors, reflecting the active gating of distracting information from interfering with the memory trace. However, there was a lack of evidence supporting the inhibition account of alpha oscillations in later studies using similar experimental design with greater temporal disparity between the encoding phase and the presentation of the distractors. This temporal disparity might have dampened the demands for inhibition. To test the hypothesis that alpha inhibition takes place when distractors are temporally close to the encoding phase, here we designed a modified Sternberg paradigm where distractors were sandwiched between targets in the encoding phase to ensure that they compete for working memory resources. Using electroencephalography (EEG), we replicated the finding that alpha power increased for strong compared to weak distractors. The effect was present throughout the encoding phase, not only upon the presentation of distractors but also before and after the presentation of distractors, providing evidence for both proactive and reactive inhibition of distractors at the neuronal level. Meanwhile, the effect was restricted to the context of high but not low target-to-distractor ratio. The results suggest that the distractors being temporally close to the encoding phase of more targets might be a boundary condition of the generation of alpha oscillations for gating.
阿尔法振荡被认为具有抑制功能，以保护工作记忆中的项目免受干扰信息的影响。在一个改良的斯特恩伯格范式中，最初发现与弱干扰物相比，在预期强干扰物时阿尔法功率会增加，这反映了对干扰信息的主动门控，以防止其干扰记忆痕迹。然而，在后来使用类似实验设计的研究中，编码阶段和干扰物呈现之间的时间差异更大，缺乏支持阿尔法振荡抑制作用的证据。这种时间差异可能削弱了抑制的需求。为了检验当干扰物在时间上接近编码阶段时会发生阿尔法抑制的假设，我们设计了一个改良的斯特恩伯格范式，在编码阶段将干扰物夹在目标之间，以确保它们竞争工作记忆资源。使用脑电图（EEG），我们重复了与弱干扰物相比，强干扰物的阿尔法功率增加的发现。这种效应在整个编码阶段都存在，不仅在干扰物呈现时，而且在干扰物呈现之前和之后，这为神经元水平上对干扰物的主动和反应性抑制提供了证据。同时，这种效应仅限于高目标与干扰物比例而非低目标与干扰物比例的情况。结果表明，干扰物在时间上接近更多目标的编码阶段可能是产生用于门控的阿尔法振荡的一个边界条件。
