Pedunculopontine nucleus

From Wikipedia, the free encyclopedia

The pedunculopontine nucleus (PPN) (or pedunculopontine tegmental nucleus) is located in the brainstem, caudal to the substantia nigra and adjacent to the superior cerebellar peduncle. It is composed by a wide variety of neurochemical cell types, including cholinergic, glutamatergic and GABAergic cells. The PPN has been classically considered as one of the main components of the reticular activating system.

One of the distinctive characteristics of the PPN is the wide range of its projections. PPN neurons send their axons to several targets in the thalamus, basal ganglia, cerebral cortex, basal forebrain, and lower brainstem. A particularly interesting area for the study of PPN projections is the basal ganglia, due to the high level of interconnectivity between them.The complex receives direct afferences from the medial pallidum.

The PPN is involved in many functions, including arousal, attention, learning, reward, and locomotion. It is also implicated in the generation and maintenance of REM sleep.

[edit] External links

• NeuroNames hier-495
• MeSH Pedunculopontine+Tegmental+Nucleus
• Images of the Pedunculopontine Nucleus

Mesencephalon (midbrain)

cerebral peduncle: midbrain tegmentum (periaqueductal gray, ventral tegmentum, nucleus raphe dorsalis), pretectum, substantia nigra, red nucleus, pedunculopontine nucleus, medial longitudinal fasciculus, medial lemniscus, rubrospinal tract, lateral lemniscus tectum: corpora quadrigemina, inferior colliculi, superior colliculi cerebral aqueduct: oculomotor nucleus, trochlear nucleus, Edinger-Westphal nucleus