Midbrain

The midbrain—also called the mesencephalon—is the smallest portion of the brain and is located just above the brain stem.

What Is the Midbrain?

The midbrain is located in between the forebrain and hindbrain. It is underneath the cerebral cortex, just above the brain stem, and is located toward the center of the brain.

Parts of the Midbrain

Like other parts of the brain, the midbrain is composed of a complex set of parts as well as clusters of neuronal cells. Major parts of the midbrain include:

• The reticular formation, which is a component of the tegmentum. This region plays a role in motor function.
• The crus cerebri, which contains the substantia nigra, a structure which is further divided into the pars reticula and pars compacta.
• The superior and inferior colliculi are two rounded components located near the top of the midbrain that play a role in vision and hearing.
• The thalamus, a portion of the brain that integrates and sends sensory information, and the hypothalamus, which controls the autonomic nervous system.
• The hippocampus, which plays an important role in short-term memory.
• The basal ganglia, which enables many motor functions and plays a role in Parkinson’s disease.
• The Pineal body, which synthesizes melatonin.
• The corpus callosum, which links the two brain hemispheres.

Role of the Midbrain

The midbrain serves many roles, including motor function. It also plays a major role in receiving and integrating sensory information, particularly visual and auditory input. Damage to the midbrain can result in a wide variety of movement disorders, difficulty with vision and hearing, and trouble with memory. Because the midbrain houses the hypothalamus, it also plays a major role in automatic body functions.

References:

1. Midbrain. (n.d.). Encyclopedia Britannica Online. Retrieved from http://www.britannica.com/EBchecked/topic/380850/midbrain
2. Midbrain. (n.d.). Family Hope Center. Retrieved from http://www.familyhopecenter.org/midbrain/

Last Updated: 08-11-2015