The dream, the remains of the night

The term ‘dream’ defines the specific mental activity of the physiological condition of sleep. This experience has a multisensory quality, with the dreamer’s visual hallucination and participation. The dream occurs in very particular psychophysiological conditions (sleep) and consists of contents linked to mnestic activation. The analysis of accounts of dreams collected in the laboratory under electropoligraphic control has made it possible to assess the differences related to cortical activation during the different phases of sleep. Based on the experimental data, we discuss some fundamental aspects of the dream experience. The first aspect relates to the genesis of the dreamlike hallucinatory process. This cognitive process allows, under normal conditions, to distinguish the internal (representative) from the external (phenomenal) origin of a visual experience: in other words, it distinguishes a mental representation from a phenomenal perception. A second aspect concern ‘the matter of dreams’, namely the activation of memories that constitute the contents of the dream.