2-Minute Neuroscience: Midbrain Video Lecture | A-Z Guide to Neuroscience - Personal Learning

Welcome to 2 minute neuroscience, where I
explain neuroscience topics in 2 minutes or
less.
In this installment I will discuss the midbrain.
The midbrain is one of the three divisions
of the brainstem.
At the level of the midbrain, the fourth ventricle
has narrowed to form the cerebral aqueduct,
which connects the third and fourth ventricles.
The region of midbrain behind the cerebral
aqueduct is called the tectum.
The area in front of the cerebral aqueduct
is called the tegmentum.
The anterolateral portion is made up of two
structures called the basis pedunculi.
The tectum primarily consists of the superior
and inferior colliculi---clusters of neurons
that together form 4 bumps on the posterior
surface of the brainstem.
The superior colliculi are thought to be involved
with directing behavioral responses toward
stimuli in the environment, while the inferior
colliculi are known for their role in auditory
processing.
The tegmentum contains a variety of ascending
and descending tracts, like the medial lemniscus
and anterolateral tracts.
It also contains fibers from the superior
cerebellar peduncles, the main output pathway
of the cerebellem, and the red nucleus---a
nucleus thought to play a role in motor coordination.
The tegmentum contains nuclei for cranial
nerves III and IV as well as neurons that
are part of the raphe nuclei---the major serotonin
producing neurons in the brain, and the ventral
tegmental area---one of the largest collections
of dopamine-producing neurons in the brain.
The basis pedunculi include the crura cerebri---two
large bundles of axons that contain fibers
from motor pathways like the corticospinal
and corticoblulbar tracts.
The basis pedunculi also include the substantia
nigra, which is another major dopamine-producing
structure in the brain.
Finally, the area surrounding the cerebral
aqueduct is called the periaqueductal gray.
The periaqueductal gray is known for its role
in pain inhibition.