Mesencephalic reticular formation

Interpeduncular nucleus, central gray, mesencephalic reticular formation Rhombencephalon... 

The midbrain (mesencephalon) is the top of the brain stem. The dorsal midbrain is the tectum, which is involved in eye movements and reflexive reactions to sensory stimuli. The mesencephalic reticular formation projects upward to the forebrain and is involved in arousal and attention. The periaqueductal gray area surrounds the cerebral aqueduct, and integrates analgesic, defensive/aggressive, sexual, and autonomic responses. The red nucleus and substantia nigra are important structures in motor function. 

Hartgraves S L, Kelly P H. 1984. Role of mesencephalic reticular formation in choliergic- induced catalepsy and anti-cholinergic reversal of neuroleptic-induced catalepsy. Brain Res 307 47-54. 

What is the source of the activation of the thalamocortical system and the distributed forebrain circuits underlying consciousness Few neuroscientists now doubt that the brainstem reticular formation, and especially its pontine-mesencephalic and diencephalic components, regulate the cortex via its interaction with the thalamocortical system. 

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