BRAIN

WHAT DOES THE POSTERIA PART OF THE MID BRAIN CONTROLL

[jenny2008]

The midbrain serves as the nerve pathway of the cerebral hemispheres and contains auditory and visual reflex centers.

The MidBrain or MesenCephalon, is the smallest region of the BrainStem. It is just superior to the Pons and contains the nuclei of Cranial Nerves III (Oculomotor) and IV (Trochlear).

The Tectum (Roof) of the MidBrain consists of four nuclei that form mounds on the dorsal surface, collectively called Corpor (Bodies) Quadrigemina (Four Twins). Each mound is called a Colliculus (Hill); there are two Superior Colliculi and two Inferior Colliculi.

The Inferior Colliculi:
Are involved in Hearing and are an integral portion of the Auditory Pathways in the CNS. Neurons conducting impulses from the structures of the Inner Ear to the Brain, all synapse in the Inferior Colliculi.

The Superior Colliculi:
Are involved in Visual Reflexes, and they receive input from: the Eyes; the Inferior Colliculi; the Skin; and the Cerebrum. The Superior Colliculi regulate the reflexive movement of the Eyes and Head, in response to a number of different stimuli.

Fibers from the Superior Colliculi project to Cranial Nerve Nuclei and to the Superior Cervical portion of the Spinal Cord where, they stimulate Motor Neurons involved in turning the Eyes (Oculomotor, Trochlear, and Abducens Cranial Nerves) and the Head (the Accessory Cranial Nerve and Superior Cervical Cord Levels).

Impulses reaching the Superior Colliculi from the Cerebrum are involved in the Visual tracking of moving objects.