Retrospective attention reveals a decaying theta rhythm in conscious access to a preceding stimulus

Conscious perception is often presumed to arise immediately upon external stimulation. However, the phenomenon of retroperception-conscious access to a stimulus after it has disappeared-challenges this view by demonstrating that awareness can emerge retrospectively. The fine-grained temporal dynamics governing this process, however, remain unknown. Here, we tested three competing models for the temporal architecture of retroperception: a monotonic decay, a sustained oscillation, and a damped oscillation. We implemented an established retro-cue paradigm and densely sampled behavioral reports. Through spectral analysis and computational modeling, we revealed that both behavioral accuracy and subjective visibility exhibited damped oscillations in the theta-band, superimposed on a time-dependent decay. Furthermore, we demonstrated that these oscillations in accuracy and visibility were temporally aligned, advocating a functional interplay between attention and perception in the post-stimulus period. These results reveal a rhythmically structured and temporally constrained window for conscious reactivation, redefining the limits of when and how the mind can become aware of the past.