Shanghai Key Laboratory of Psychotic Disorders, Shanghai Mental Health Center, Shanghai Jiao Tong University School of Medicine, Shanghai 200030, China.
Institute of Psychology and Behavioral Science, Shanghai Jiao Tong University, Shanghai 200030, China.
Cereb Cortex. 2023 Aug 23;33(17):9741-9755. doi: 10.1093/cercor/bhad240.
The human brain can utilize various information to form temporal expectations and optimize perceptual performance. Here we show dissociated amplitude and phase effects of prestimulus alpha oscillation in a nested structure of rhythm- and sequence-based expectation. A visual stream of rhythmic stimuli was presented in a fixed sequence such that their temporal positions could be predicted by either the low-frequency rhythm, the sequence, or the combination. The behavioral modeling indicated that rhythmic and sequence information additively led to increased accumulation speed of sensory evidence and alleviated threshold for the perceptual discrimination of the expected stimulus. The electroencephalographical results showed that the alpha amplitude was modulated mainly by rhythmic information, with the amplitude fluctuating with the phase of the low-frequency rhythm (i.e. phase-amplitude coupling). The alpha phase, however, was affected by both rhythmic and sequence information. Importantly, rhythm-based expectation improved the perceptual performance by decreasing the alpha amplitude, whereas sequence-based expectation did not further decrease the amplitude on top of rhythm-based expectation. Moreover, rhythm-based and sequence-based expectations collaboratively improved the perceptual performance by biasing the alpha oscillation toward the optimal phase. Our findings suggested flexible coordination of multiscale brain oscillations in dealing with a complex environment.
人类大脑可以利用各种信息形成时间预期，并优化感知表现。在这里，我们展示了在基于节奏和序列的预期嵌套结构中，刺激前 alpha 振荡的幅度和相位效应的分离。视觉流的节奏刺激以固定的序列呈现，使得它们的时间位置可以通过低频节奏、序列或组合来预测。行为建模表明，节奏和序列信息可累加地提高感觉证据的积累速度，并减轻对预期刺激的感知辨别力的阈值。脑电图结果表明，alpha 幅度主要受节奏信息调制，幅度随低频节奏的相位波动（即相位-幅度耦合）。然而，alpha 相位受到节奏和序列信息的双重影响。重要的是，基于节奏的预期通过降低 alpha 幅度来提高感知性能，而基于序列的预期在基于节奏的预期之上并没有进一步降低幅度。此外，基于节奏和序列的预期通过将 alpha 振荡偏向最佳相位来协同提高感知性能。我们的研究结果表明，在处理复杂环境时，多尺度脑振荡可以灵活协调。
