NT, promotes wakefulness, NE levels in LC, amygdala, nucleus, accumbens, and prefrontal cortex greater during wakefulness than during sleep. most importantly LC.
REM sleep characteristics
Rapid eye movement sleep, aka paradoxical sleep. Characterized by rapid eye movements, muscle atonia, cortical activation. Occurs ~ 90 mins. after sleep onset, and in ~90 min. intervals after first REM stage. Irregular respiration and heart rates, and body temp. Dreaming usually occurs during REM.
REM sleep generation/inhibition
REM sleep generating neurons localized to pons. 5-HT and NE inhibit REM
Inhibits REM, promotes arousal. 5-HT levels in the dorsal raphé nucleus (DR), cortex, and thalamus are greatest during wakefulness, intermediate in NREM sleep, and lowest during REM sleep. However, can have biphasic effect on wakefulness by contributing to the production of one or more sleep-enhancing substance, or inhibiting wakefulness producing neurons.
ACh release high during high cortical activity (REM and Wake). Promotes REM. AChergic neurons located Basal Forebrain and LDT/PPT. ACh Release in the PRF is Greatest during REM Sleep. LDT/PPT cholinergic neurons are REM-On and Wake On/REM-On. Basal forebrain ACh lowest during NREM.
Increases wakefulness. DAergic neurons of importance project located in ventral tegmental area (VTA) and substantia nigra, project to dorsal raphe nucleus (DR), locus coeruleus, LDT/PPT, basal forebrain and thalamus. Mean firing rate stable across sleep states, but variability is significantly different. In prefrontal cortex and nucleus accumbens, DA levels higher in W and REM than NREM.