Pedunkulopontina tegment core.

Nucleus tegmentalis pedunculopontinus.

TPP core, TPC core, PPN, PPT core

The core, a t.hay. and one left, is included in formatio reticularis with strong links to the basal ganglia and contains the acetylcholine-producing cell group Ch5 as well as more widespread GABAergic and glutamatergic neurons.
The nucleus is adjacent to the upper part of the nucleus cuneiformis and is thus located in the mesencephalic locomotor region.

The TPP nucleus consists of two subdivisions: the caudal cholinergic pars compacta (TPC nucleus) and the rostral, more scattered, pars dissipata .

The TPP nucleus has a well-developed round-trip traffic with the basal ganglia, especially with the braking GPi-SNr and the driving nucleus subthalamicus , as well as transmitting threads to the formatio reticularis of the pons and medulla oblongata, to the cerebellum in the form of moss filaments and to the spinal cord.

The question of whether the TPP nucleus should be included in the basal ganglia or not is under discussion.

Note that nerve fibers from the TPC portion form the main part of the ascending reticular activation system, ARAS, which, via switching in the thalamus, activates, "wakes up", the cerebral cortex. The TPC nucleus receives, not unexpectedly, an influx of signals from orexin-positive neurons in the hypothalamus.

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Benarroch E. Pedunculopontine nucleus. Functional organization and clinical implications. Neurology 2013; 80: 1148-1155.
Mena-Segovia J, Bolam JP, and Magill PJ. Pedunculopontine nucleus and basal ganglia: distant relatives or part of the same family?
Trends in Neurosciences 2004; 27: 586-588.