Taking an opposite standing point of dualism, we take an enactive approach to understanding human cognition. We focus on the interaction between perception and action. On the one hand, we are interested in how humans build up knowledge about the world through explorative action, ranging from basic perception to high-level cognition such as belief. On the other hand, we are interested in how humans make action choices under the guidance of knowledge. We use a combination of techniques such as eye-tracking, EEG, fMRI, and MEG to understand the neural mechanism.

We live in a world teemed with temporal regularities: day and night alternate with each other approximately every 12 hours; the thunder is always heard after the seeing of the lightning. Such temporal regularity affords the temporal expectation of an event, which avails to guide perception and action that serve the current goal. The human brain can utilize various information to form temporal expectation and optimize perceptual performance. In our recent work published in Cerebral Cortex, we show dissociated amplitude and phase effects of pre-stimulus 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 modelling indicated that rhythmic and sequence information additively led to increased accumulation of sensory evidence and alleviated threshold for the perceptual discrimination of the expected stimulus. The electroencephalographical (EEG) 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 expectation 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.

Article access：https://doi.org/10.1093/cercor/bhad240