ABSTRACT
Neural basis of consciousness and its suppression are typically studied by manipulating stimuli around the conscious access threshold, or – alternatively – by contrasting conscious and unconscious states (i.e. awake/sleep). Here we show that behavioural and neural markers of conscious access are dependent on wakefulness state, and thus a comprehensive description of the neural basis of conscious access requires an integrated assessment of the state of consciousness. In particular, we demonstrate that a distinctive steepness of a behavioural slope of conscious access is severely compromised during the transition to sleep. Likewise, electrophysiological markers show a delayed processing of target-mask interaction during drowsiness. Consequently, the resolution of conscious access shifts from perceptual to executive stages of processing in the drowsy state of consciousness. Once the goal is set – to report the awareness of a target – the brain is capable to adapt to rapidly changing wakefulness states, revealing that the neural signatures of conscious access and its suppression may not be hard-wired but flexible to maintain performance.