关键词: 节律线索, 时间注意, 意识状态, 分层漂移扩散模型, CNV

Abstract: Temporal cues enable individuals to anticipate upcoming events, thereby facilitating goal-directed behavior. While temporal association cues are known to engage endogenous temporal attention that is modulated by conscious perception, it remains unclear whether rhythmic cues—typically considered to evoke exogenous temporal attention—are similarly affected by the state of consciousness. Addressing this gap, the present study investigated whether rhythmic temporal attention is subject to modulation by conscious awareness and whether it involves endogenous cognitive components akin to those recruited by symbolic temporal cues.
Two experiments were conducted, each involving 24 different Chinese participants and comprising three conditions: (a) a rhythmic cueing task under conscious perception, (b) the same task under unconscious perception manipulated via high-frequency flicker (50 Hz), and (c) a two-alternative forced-choice awareness check. Experiment 2 replicated the design of Experiment 1 with simultaneous EEG recordings. Participants performed an orientation discrimination task in rhythmic versus random cue conditions, with inter-stimulus intervals (ISIs) of either 800 ms or 1300 ms to compare sub-second and supra-second timing.
Behavioral results showed robust temporal attention effects in both conscious and unconscious states, though significantly larger under conscious perception. ERP analyses revealed that rhythmic cues elicited greater contingent negative variation (CNV) amplitudes when participants were conscious, indicating enhanced temporal preparation at the neural level. Hierarchical drift-diffusion modeling (HDDM) further showed that under conscious perception, rhythmic cues reduced decision boundaries, suggesting more confident and efficient decision-making—a hallmark of endogenous control. These effects were absent under unconscious conditions. Additionally, faster responses in supra-second versus sub-second intervals support the segmented timing hypothesis and indicate that longer temporal contexts may recruit higher-order cognitive processes. Importantly, time-frequency analysis revealed stronger alpha-band (8~12 Hz) suppression during the rhythmic encoding phase under conscious perception, particularly over frontal and occipital regions, with wider spatial distribution in the supra-second interval. This enhanced alpha desynchronization suggests greater attentional engagement and top-down modulation of sensory areas, supporting the notion that conscious perception of rhythmic structure facilitates the neural entrainment of anticipatory attention.
Together, these findings challenge the view that rhythmic temporal attention is purely exogenous, showing instead that it contains an endogenous component that is modulated by the state of consciousness. This study provides converging behavioral, electrophysiological, and computational evidence for a dual-process account of rhythmic temporal attention and offers novel insights into the interaction between temporal structure and awareness in shaping anticipatory cognition.

Key words: rhythmic cues, temporal attention, consciousness states, hierarchical drift-diffusion modeling, contingent negative variation