The concepts of consciousness and unconsciousness, and their respective stages, are of particular interest in the domain of neuroscience, philosophy and psychology. This study aims to investigate the brain's response to visual stimuli, with a specific focus on differentiating between conscious perception and the subliminal and preconscious stages of unconscious perception. The study used two experimental paradigms to test three hypotheses, evaluating the predictions of the Global Neural Workspace Theory (GNWT) regarding the spread of cerebral activation during information processing. The research aimed to analyse the VAN and P300 waves as indicators of visual stimulus perception and neural correlates of consciousness, as well as exploring additional non-conventional EEG parameters as potential consciousness indicators.