Perceiving is the process by which evanescent sensations are linked to environmental cause and made enduring and coherent through the assignment of meaning, utility, and value. Fundamental to this process is the establishment of associations over space and time between sensory events and other sources of information. These associations provide the context needed to resolve the inherent ambiguity of sensations. Recent studies have explored the neuronal bases of contextual influences on perception. These studies have revealed systems in the brain through which context converts neuronal codes for sensory events into neuronal representations that underlie perceptual experience. This work sheds light on the cellular processes by which associations are learned and how memory retrieval impacts the processing of sensory information. Collectively, these findings suggest that perception is the consequence of a critical neuronal computation in which contextual information is used to transform incoming signals from a sensory-based to a scene-based representation.