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

Welcome to 2 minute neuroscience, where I
simplistically explain neuroscience topics
in 2 minutes or less.
In this installment I will discuss the substantia
nigra.
The substantia nigra is a structure found
in the brainstem that looks like a dark streak
in unstained brain tissue.
Its appearance is where it gets its name,
as substantia nigra is Latin for “black
substance.”
There are two substantiae nigrae, one on each
side of the midline of the midbrain.
The substantia nigra is actually made up of
two distinct regions: the substantia nigra
pars compacta and the substantia nigra pars
reticulata.
The substantia nigra gets its dark coloring
from the large number of dopamine neurons
in the substantia nigra pars compacta, as
they express high levels of a dark pigment
called neuromelanin.
In fact, most of the dopamine-producing neurons
of the brain are found in either the substantia
nigra or an adjacent area called the ventral
tegmental area.
The dopamine neurons in the substantia nigra
are primarily found in the substantia nigra
pars compacta, as the substantia nigra pars
reticulata is more heavily populated with
GABA neurons.
The substantia nigra is considered part of
the basal ganglia, and many of the dopamine
neurons in the substantia nigra pars compacta
project to two other structures of the basal
ganglia, the caudate and putamen (which together
are referred to as the striatum).
These dopamine neurons make up a large bundle
of fibers called the nigrostriatal pathway.
The nigrostriatal pathway is one of the major
dopamine pathways in the brain, and is thought
to be extremely important in the facilitation
of movement.
The GABA neurons of the substantia nigra pars
reticulata also play important roles in movement,
and thus movement is one of the main functions
of the substantia nigra.
The substantia nigra also has many functions
beyond motor control, however the role for
the substantia nigra in movement is particularly
emphasized when we observe the symptoms of
Parkinson’s disease, a neurodegenerative
disorder that involves the death of dopamine
neurons in the substantia nigra.
Individuals suffering from Parkinson’s disease
display severe movement-related deficits.