Neurobiología del sueño

Abstract

8646

Sleep is active, necessary, periodic, varied and complex. The present  review considers three phases in the sleep-wakefulness cycle (SWC):  wakefulness, Non-REM sleep and REM sleep. The SWC is sustained  by a broad neuronal net that extends, directly or indirectly, to the  entire nervous system. However, there are nervous structures that are  necessary for organising each phase of the cycle. The structures  responsible for each phase of the cycle and the neurotransmitters  utilized are studied here. The state of wakefulness is organised by the  neuronal groups of the ponto-meso-diencephalic reticular formation  and the basal forebrain; the main neurotransmitters involved are  noradrenaline, serotonin, acetylcholine, glutamate, histamine, orexine  and GABA. The essential structures for Non-REM sleep generation  are: the reticular and dorsomedial thalamic nuclei, the cerebral cortex,  the basal forebrain-anterior hypothalamic region, and the caudal  pontine tegmentum; the main neurotransmitters involved are GABA  and glutamate. In REM sleep a neuronal net extending widely through  the brainstem tegmentum is responsible for the organisation of the  different bioelectric signs associated with this sleep state. This network  is organised and directed by the ventral part of the oral pontine reticular  nucleus. The different structures for each SWC state are closely  connected. Moreover, and very importantly, the structures responsible  for each state of the SWC are connected with the structures responsible  for the other phases of the cycle. These complex patterns of connections  -acting through processes of excitation/inhibition- allow the cycle  states to alternate under the temporal pacing of the suprachiasmatic  nucleus and modulated by the inputs received from other structures of  the central nervous system.  

Keywords

Wakefulness, Non-REM sleep, Slow waves sleep, REM sleep, Sleep-wakefulness cycle, Paradoxical sleep