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
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.