Brain-body timing gates conscious access across sensory systems
Conscious awareness fluctuates with the brains internal state at the moment of perception, yet how these states are temporally coordinated remains unclear. Although such internal states are reflected in ongoing neural activity, their temporal structure may arise from intrinsic interactions between the brain and the body. To test this hypothesis, we simultaneously recorded neural, cardiac, and respiratory activity while participants detected auditory, tactile, or visual stimuli presented at perceptual threshold. Across sensory modalities, stimulus detection was preceded by transient bursts of alpha-band (8-13 Hz) activity localized to lateralized prefrontal and premotor regions. Crucially, these neural events were aligned with specific phases of the cardiac and respiratory cycles, revealing coordinated brain-body states at the time of perception. This cross-system coupling predicted whether sensory stimuli reached conscious awareness. Together, these findings show that brain-body synchrony acts as a temporal gate for conscious access across sensory systems.