Long-timescale dynamics shape visual conscious awareness

Abstract

Consciousness is mostly studied as if it were composed of independent snapshots, aggregating reports over trials and experimental contexts, disregarding any temporal aspect. However, almost nothing is known about how conscious experience spontaneously fluctuates in time. To shed light on the temporal dynamics of conscious awareness, we evaluated the temporal autocorrelation of subjective visibility/confidence reports and objective performance across 20 datasets (N= 335). Two widely used measures of consciousness dissociate in temporal autocorrelation under full spatial attention: subjective measures followed an exponential decay function with long timescales (> 5s), whereas objective accuracy exhibited a slow linear decay function. But both measures share a common underlying temporal fluctuation dynamics, suggesting that the strong autocorrelation in subjective measures cannot be fully attributed to response bias or criterion shift, but might reflect a genuinely aperiodic fluctuation of conscious awareness. Causal transcranial magnetic stimulation (TMS) suggests that this temporal dependency of subjective measures is read out in the dorsolateral prefrontal cortex (DLPFC), where a similarly long neural timescale has been demonstrated. Together, these findings establish a temporal constraint for neural models of conscious access: candidate mechanisms should explain not only whether a stimulus becomes consciously accessible, but also how the probability of conscious access evolves over time.