Notes on Brains

"Helmholtz contended that this seamless flow is accomplished by referring the central displays of sensory stimuli to "mental constructs" of the world and events within it. These constructs are thought to be generated by past experience and to be stored in and readily recalled from memory. Perceptions are then thought to be produced by the comparison of recalled and evoked neural images and perceptual identification inferred by the likeness between them, the simplest and most appropriate recalled construction winning the day. On this hypothesis, perhaps what we perceive are patterns of neural activity recalled from memory for the matching operation, rather than the activity evoked directly by sensory stimuli themselves."
(Mountcastle, Perception and the Cerebral Cortex)