Pontine tegmentum

The pontine tegmentum is a part of the pons of the brain involved in the initiation of REM sleep. It includes the pedunculopontine nucleus and the laterodorsal tegmental nucleus, among others, and is located in close proximity to the raphe nucleus and the locus ceruleus.

Animal studies have shown that lesions of the pontine tegmentum can greatly reduce or even eliminate REM sleep. Injection of a cholinergic agonist (e.g. carbachol), into the pontine tegmentum produces a state of REM sleep in cats.

PET studies seem to indicate that there is a correlation between blood flow in the pontine tegmentum, REM sleep, and dreaming.

Pontine waves (P-waves, or ponto-geniculate-occipital waves) are brain waves generated in the pontine tegmentum. They can be observed in mammals, precede the onset of REM sleep, and continue throughout its course. After periods of memory training, P-wave density increases during subsequent sleep periods in rats. This may be an indication of a link between sleep and learning.

The trapezoid body is part of the pontine tegmentum.