What is going to happen next? Natural stimuli tend to follow each other in a reproducible way. Multiple fields of neuroscience and psychology bring evidence that human’s brain and behavior are sensitive to the temporal structure of stimuli and are able to exploit them in multiple ways: to make appropriate decisions, encode efficiently information, react faster to predictable stimuli or orient attention towards surprising ones… Multiple brain areas show sensitivity to the temporal structure of events. However, all areas do not seem to be sensitive to the same kind of temporal regularities. Conscious access to the stimuli seems to play a key role in some of these dissociations and better understanding this role could improve the current diagnostic tools for non-communicative patients. This thesis explores the hierarchical organization of the processing of temporal regularities and the computational properties of conscious and unconscious levels of processing by combining a modeling approach with neuroimaging experiments using magnetoencephalography and electroencephalography (MEEG). First, a plausible neuronal model based on predictive coding principles reproduces the main properties of the preattentive processing of pure tones in the auditory cortex indexed by the evoked potential mismatch negativity (MMN). Second, a MEEG experiment provides evidence for a hierarchical organization of multiple predictive processes in the auditory cortex. Finally, a second model explores the new computational properties and constraints associated to the access of stimuli to a conscious space with a working memory able to maintain information for an arbitrary time but with limited capacity.