Regulation of Wakefulness and REM Sleep by the Pedunculopontine Tegmentum

Primary Functions of the PPT in Sleep

The pedunculopontine tegmentum (PPT) contains cholinergic neurons that are crucial for the regulation of both wakefulness and REM sleep, serving as part of the ascending reticular activating system, as noted by the American Academy of Sleep Medicine 1

Cholinergic neurons from the PPT inhibit "REM-off" cells and thus promote REM sleep through acetylcholine release that acts on muscarinic receptors, according to the American Academy of Sleep Medicine 1
Serotonergic inputs from raphe nuclei inhibit REM sleep, as reported by the American Academy of Sleep Medicine 1
Noradrenergic inputs from locus coeruleus inhibit REM sleep, as noted by the American Academy of Sleep Medicine 1
Dopaminergic pathways influence PPT activity, with decreased striatal dopamine transporters observed in REM sleep behavior disorder, as observed by the American Academy of Sleep Medicine 1

Dysfunction of the PPT is implicated in REM Sleep Behavior Disorder (RBD), which may involve abnormal GABAergic basal ganglia output to the PPT, disrupting normal muscle atonia during REM sleep, as reported by the American Academy of Sleep Medicine 1