A central question in psychology and neuroscience is how the brain generates and sustains our conscious experiences. While much research has focused on how stimuli enter awareness, less is known about how these experiences persist and whether they remain tightly linked to sensory input. We addressed this question in two studies exploring the neural and behavioral dynamics of sustained visual stimuli. In the first study, we presented visual stimuli of varying duration (0.5, 1.0, and 1.5 seconds) while recording brain activity using intracranial EEG. We found that sensory regions in the posterior cortex reflected the duration of the stimuli, while prefrontal cortex (PFC) activity occurred only briefly at the start of each stimulus. Under the assumption that participants' experience aligns with stimulus dynamics, these results challenge theories assuming that the PFC plays a central role in conscious experience, such as the global workspace theory (GNWT). However, our second study adds nuance to this interpretation. Using the psychological refractory period (PRP) as a time-resolved measure of conscious engagement, we found that the PRP effect was independent of stimulus duration and did not consistently coincide with stimulus offset. This suggests that conscious processing is not always tightly coupled to sensory input dynamics. Combined, these findings indicate that conscious processing may become decoupled from sensory input, even under simple conditions. This offers fresh insights into the complex relationship between sensory input, cognition, and conscious experience, with important implications for theories of consciousness.