Abstract

RAMIREZ-SALADO, Ignacio  and  CRUZ-AGUILAR, Manuel Alejandro. The origin and functions of dreams based on the PGO activity. Salud Ment [online]. 2014, vol.37, n.1, pp.49-58. ISSN 0185-3325.

Understanding the phenomenon of sleep and dreams has fascinated humans always. However, the scientific study of sleep is relatively recent. In 1953, Aserinsky and Kleitman found that slow wave sleep (SWS) was periodically interrupted by episodes of rapid EEG activity, which are accompanied by rapid eye movements (REMs), and named this sleep phase as REM sleep. Subsequently, in 1957, Dement and Kleitman discovered that these rapid eye movements coincided with the appearance of dreams. By using animal experimental models, the subcortical mechanisms underlying REM sleep have been studied, and it has been demonstrated that this activity depends on the serotonergic activity from wakefulness, which promotes the formation of peptides that trigger certain structures of the brainstem, where cholinergic mechanisms of REM sleep are integrated. In turn, on the pontine region monophasic phasic potentials (300-400 uV) are generated that can also be recorded on the lateral geniculate body and in the occipital cortex; hence the name of ponto-geniculo-occipital waves (PGO). These potentials spread to the oculomotor system to provoke the REMs of REM sleep and possibly give rise to visual hallucinatory phenomena. Furthermore, it has been shown that certain limbic structures related to emotion and memory are activated by these potentials. This suggests that PGO waves generate mnemonic and emotional components of dreams. Several aspects of the functions of these PGO waves remains to be determined, but knowledge about the origin of brain phenomena that generate dreams has had a breakthrough from its study. In the present work we review the literature concerning the work done over PGO waves and its contribution to the knowledge of the origin and functions of dreams.

Keywords : Dreams; PGO; consciousness.

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