Brainstem Genesis and Thalamic Transfer of Pontogeniculooccipital Waves

Abstract

Pontogeniculooccipital (PGO) waves are stigmatic events of REM sleep, the sleep stage when dreaming episodes occur. PGO waves are generated in different neuronal groups of the brainstem reticular core and are transferred to many thalamocortical systems in addition to the visual one where they were originally thought to be confined. Interest in the PGO waves stemmed from the discovery that eye movement direction may be related to gaze direction in dream imagery, coupled with data from animal experiments showing that saccadic REMs are often coincident with PGO events (Dement and Kleitman, 1957; Jouvet, 1972). These observations led to the thesis that PGO waves are physiological correlates of brain activation during dreaming sleep, a major part of “the stuff that dreams are made of.”