Pedunculopontine nucleus

Pedunculopontine nucleus (PPN or PPNc) is a collection of neurons located in the brainstem. It is named for its proximity to the cerebral peduncle and the pons, two major structures in the brain's midbrain and hindbrain regions, respectively. The PPN is involved in many functions, including locomotion, sleep, and reward.

Etymology

The term "pedunculopontine" is derived from Latin. "Pedunculus" means "little foot," referring to the cerebral peduncle, and "pontine" refers to the pons. The "nucleus" in the name refers to a collection of neurons.

Anatomy

The Pedunculopontine nucleus is located in the upper part of the brainstem, between the substantia nigra and the cerebellum. It is part of the reticular formation, a set of interconnected nuclei that are involved in multiple tasks such as regulating the sleep-wake cycle and filtering incoming sensory information.

Function

The PPN is involved in a variety of functions. It plays a role in locomotion by sending signals to the spinal cord, and it is involved in the regulation of sleep and wakefulness. The PPN also plays a role in reward processing, as it receives inputs from the limbic system, a part of the brain involved in emotions and motivation.

Clinical significance

Damage to the PPN can lead to a variety of neurological and psychiatric disorders. For example, it has been implicated in Parkinson's disease, a neurodegenerative disorder characterized by motor symptoms such as tremors and rigidity. The PPN is also involved in REM sleep behavior disorder, a condition in which people act out their dreams during REM sleep.

See also

• Brainstem
• Cerebral peduncle
• Pons
• Reticular formation
• Limbic system

Pedunculopontine nucleus gallery

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  The nuclei of the Modulatory network