Brainstem -- tegmentum not labeled, but is visible near center
|NeuroLex ID||Pontine tegmentum|
|Anatomical terms of neuroanatomy|
The pontine tegmentum is a part of the pons of the brain involved in the initiation of REM sleep. Throughout its entire length, the pons can be divided anatomically into ventral and dorsal pons: Dorsal pons is known as the pontine tegmentum, whilst the ventral pons is known as the basilar pons. Basilar pons may be considered the rostral extension of the ventral medulla oblongata, which contains the corticospinal tract running craniocaudally. Ventral pons is different to ventral medulla in that it contains additional transverse pontine fibres that continues laterally to become the middle cerebellar peduncle, entering the cerebellar cortex. The pontine tegmentum then, can be considered to be the collection of all the nuclei, neuronal and glial substance dorsal to the basilar pons defined above.
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