|Brain: Pontine tegmentum|
Brainstem -- tegmentum not labeled, but is visible near center
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 near the raphe nucleus and the locus ceruleus.
In animal studies, lesions of the pontine tegmentum 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.
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.
- Atlas image: n2a3p2 at the University of Michigan Health System