Welcome to 2 minute neuroscience, where I simplistically explain neuroscience topics
in 2 minutes or less.
In this installment I will discuss the striatum.
Striatum is a term used to collectively refer to a small group of structures found below
the cerebral cortex.
These structures consist of the caudate, putamen, and nucleus accumbens.
The caudate and putamen are separated from one another by a white matter tract called
the internal capsule, but there are many strands of grey matter that cross the internal capsule,
giving the structure a striped appearance.
This is why the term striatum, Latin for striped, is used to describe the region.
The striatum is often conceptualized a being divided into dorsal and ventral sections;
the dorsal striatum contains the caudate and putamen while the ventral striatum contains
the nucleus accumbens.
The striatum is one of the principal components of the basal ganglia, a group of structures
best known for their role in facilitating movement.
The dorsal striatum is one of the primary input areas for the basal ganglia, and fibers
from the cerebral cortex, substantia nigra, and thalamus all enter the basal ganglia via
the dorsal striatum.
The incoming fibers from the substantia nigra, which make up a pathway called the nigrostriatal
pathway, are thought to be especially important to movement and are severely affected by neurodegeneration
in patients with Parkinson’s disease.
The nucleus accumbens, part of the ventral striatum, has been extensively studied for
its role in rewarding experiences.
The nucleus accumbens seems to be involved in reinforcement, reward, and the progression
from simply experiencing something pleasurable to seeking it out compulsively as part of
The ventral striatum is thus activated when we do something we find pleasurable.
The nucleus accumbens receives fibers from a dopamine-rich structure in the midbrain
called the ventral tegmental area.
These fibers are part of a pathway called the mesolimbic dopamine pathway which is a
primary component of the reward system.