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2-Minute Neuroscience: The Brainstem

Welcome to 2 minute neuroscience, where I simplistically explain neuroscience topics

in 2 minutes or less. In this installment I will discuss the brainstem.

The brainstem is a stalk that leaves the base of the brain and connects the brain to the

spinal cord. It contains many important pathways that run between the brain and spinal cord

as well as pathways to other areas like the cerebellum. It also contains a large number

of important nuclei, and is essential for both survival and proper cognitive functioning.

It consists of three major divisions: the medulla oblongata, the pons, and the midbrain.

The medulla oblongata, often simply called the medulla, is the point where the brainstem

connects to the spinal cord. The medulla is essential for survival as it contains nuclei

that ensure vital systems like the cardiovascular and respiratory systems are working properly.

The medulla also contains nuclei that are responsible for a number of reflexive actions,

including vomiting, swallowing, coughing, and sneezing. Several cranial nerves also

exit the brainstem at the level of the medulla.

The next structure on our way up the brainstem is the pons. The word "pons" means bridge

in Latin, and the pons is a large, rounded structure resembling a rounded bridge that

connects the medulla and the midbrain. The pons is home to a number of nuclei for cranial

nerves and contains nuclei that deal with sensations from the head and face, motor movement

of the eyes, face, and mouth, hearing, equilibrium, and autonomic functions like tear and saliva

production.

The final branch of the brainstem as we move toward the cerebrum is called the midbrain.

On the posterior side of the midbrain we find four bumps representing two paired structures:

the superior and inferior colliculi. The superior colliculi are involved in eye movements and

visual processing, while the inferior colliculi are involved in auditory processing. The midbrain

also contains the major dopamine-producing nuclei of the brain: the ventral tegmental

area and the substantia nigra. Among other functions, the ventral tegmental area is involved

in motivation and reward while the substantia nigra plays an important role in movement.