Basic Information

  • The Midbrain is the small part of the brain directly above the pons that assimilates sensory information and realys it upward.

  • The Medulla and Pons extend upward into the Midbrain.

    • These parts also make up the brain stem. (Pons, Medulla and the Midbrain)

    • The RAS (reticular activating system) spans across all these structures.

    • The RAS serves to alert the rest of the brain to incoming signals and is involved in the sleep/ wake cycle.

  • The Midbrain's muscles controls the eye movements and the auditory reflexes.

Main components

  • The main components consist of the basis pedunculi, tegmentum and tectum.

  • The basis pedunculi and the tegmentum are concerned with motor movements.

  • The tectum however, hold visual and auditory nuclei

Major structures

  • The major stuctures of the Midbrain include the superior colliculi and the inferior colliculi (two smaller rounded prominences).

    • Together, these are called the corpora quadrigemina ("Quadruplet bodies").

  • The superior colliculi- controls the optic reflexes, such as blinking, the opening of the pupi, and the focus of the lens of the eye

  • The inferior colliculi- relay stations in the auditory pathways, adjust the ear lobe to the amount of sound coming in



Human Anatomy and Physiology By: Silverstein Copyright 1980

Understanding Psychology ~Glencoe by Richard A. Kasschau