Intrinsic fluctuations modulate thalamic gating during the emergence of human conscious perception

Human conscious perception is not determined solely by external sensory input but is also shaped by moment-to-moment fluctuations in intrinsic brain states. However, how these intrinsic states directly function after stimulus onset to shape the emergence of conscious perception remains unclear. We recorded sEEG activity in thalamus and five other consciousness-related cortical regions, while 32 patients (n= 2,023 recording sites) conscious percept a near-threshold visual stimulus. Preceding the extensively evoked consciousness-related activities, there are early activities (0-200ms after stimulus onset) exclusively appeared in high-order thalamus. These early activities inversely associated with stimulus strength, which reflected an intrinsic state that compensated for the stimulus-evoked response to reach the conscious threshold. These early activities were closer to the critical state in conscious trials, which enables more efficient information processing. These results suggest that intrinsic fluctuations in the high-order thalamus directly modulate thalamic gating during the emergence of conscious perception.