Phase-dependent amplification of working memory content and performance

Successful working memory performance has been related to oscillatory mechanisms operating in low-frequency ranges. Yet, their mechanistic interaction with the distributed neural activity patterns representing the content of the memorized information remains unclear. Here, we record EEG during a working memory retention interval, while a taskirrelevant, high-intensity visual impulse stimulus is presented to boost the read-out of distributed neural activity related to the content held in working memory. Decoding of this activity with a linear classifier reveals significant modulations of classification accuracy by oscillatory phase in the theta/alpha ranges at the moment of impulse presentation. Additionally, behavioral accuracy is highest at the phases showing maximized decoding accuracy. At those phases, behavioral accuracy is higher in trials with the impulse compared to noimpulse trials. This constitutes the first evidence in humans that working memory informationis maximized within limited phase ranges, and that phase-selective, sensory impulse stimulationcan improve working memory.

成功的工作记忆表现与低频范围内的振荡机制相关。然而，这些机制与表征记忆信息内容的分布式神经活动模式之间的相互作用机制仍不明确。在此，我们在工作记忆保持间隔期间记录脑电图（EEG），同时呈现与任务无关的高强度视觉脉冲刺激，以增强对工作记忆中所存内容相关的分布式神经活动的读取。使用线性分类器对该活动进行解码后发现，在脉冲呈现时刻，theta/alpha频段的振荡相位对分类准确率存在显著调制作用。此外，在解码准确率达到峰值的相位处，行为准确率也最高。在这些相位下，有脉冲刺激的试次中行为准确率高于无脉冲刺激的试次。这构成了人类研究中的首个证据：工作记忆信息在有限的相位范围内达到最大化，且相位选择性的感觉脉冲刺激可改善工作记忆。