Pontine Tegmentum

The pontine tegmentum (PT) is located in the brainstem, it is opposite of the ventral pons (and hence also called the dorsal pons).

It contains various cranial nerve nuclei, the pontine reticular formation, respiratory centers, and the mesopontine cholinergic system containing the pedunculopontine nucleus and the laterodorsal segmental nucleus.

Functions
Due to the cholinergic system, is implicated in switching between REM and NREM.

Cellular Composition
Can label a subset of the excitatory cells in the PT using the Atoh1 enhancer. Activating the medial population of these cells using a the hM3Dq DREADD receptor paradigm leads to a reduction of REM sleep and slight increase in NREM. Restricting the activation to primarily glutamatergic cells maintains this effect indicating a role for glutamate in REM-NREM switching (See Sleep section). Repeating this in the lateral portion results in a wake-promoting, REM-suppressing effect. The medial cells might act through GABAergic cells in the dorsal area of the deep mesencephalic nucleus.