Pedunculopontine tegmental nucleus

The pedunculopontine tegmental nucleus is located in the brainstem, caudal to the substantia nigra and adjacent to the superior cerebellar peduncle. It has two divisions, one containing cholinergic neurons, the pars compacta, and one containing mostly glutamatergic neurons, the pars dissipata. The pedunculopontine tegmental nucleus is one of the main components of the reticular activating system.

The pedunculopontine tegmental neurons project axons to a wide range of areas in the brain, particularly parts of the basal ganglia such as the subthalamic nucleus, substantia nigra pars compacta, and globus pallidus internus. It also sends them to targets in the thalamus, cerebellum, basal forebrain, and lower brainstem, and in the cerebral cortex, the supplementary motor area and somatosensory and motor cortices.

It receives inputs from many areas of the brain, including the basal ganglia to which it projects with the exception of the substantia nigra pars compacta to which it projects but does not receive, while it receives but does not project to the substantia nigra pars reticulata.

The pedunculopontine tegmental is involved in many functions, including arousal, attention, learning, reward, and voluntary limb movements and locomotion. While once thought important to the initiation of movement, recent research suggests a role in providing sensory feedback to the cerebral cortex. It is also implicated in the generation and maintenance of rapid eye mouvement sleep.

Recent research has discovered that the pedunculopontine tegmental is involved in the planning of movement, and that different networks of neurons in the pedunculopontine tegmental are switched on during real and imagined movement.