Lentiform nucleus
Encyclopedia
The lentiform nucleus or lenticular nucleus comprises the putamen
and the globus pallidus
within the basal ganglia
. It is a large, cone-shaped mass of gray matter
just lateral to the internal capsule
.
and means lens
-shaped, probably referring to the appearance of the nucleus from the side.
It is shorter than the caudate nucleus and does not extend as far forward.
and thalamus
, and is seen only in sections of the hemisphere.
It is bounded laterally by a lamina of white substance called the external capsule
, and lateral to this is a thin layer of gray substance termed the claustrum
.
Its anterior end is continuous with the lower part of the head of the caudate nucleus
and with the anterior perforated substance
.
The lateral and largest part is of a reddish color, and is known as the putamen
, while the medial and intermediate are of a yellowish tint, and together constitute the globus pallidus
; all three are marked by fine radiating white fibers, which are most distinct in the putamen.
Putamen
The putamen is a round structure located at the base of the forebrain . The putamen and caudate nucleus together form the dorsal striatum. It is also one of the structures that comprises the basal ganglia. Through various pathways, the putamen is connected to the substantia nigra and globus pallidus...
and the globus pallidus
Globus pallidus
The globus pallidus also known as paleostriatum, is a sub-cortical structure of the brain. Topographically, it is part of the telencephalon, but retains close functional ties with the subthalamus - both of which are part of the extrapyramidal motor system...
within the basal ganglia
Basal ganglia
The basal ganglia are a group of nuclei of varied origin in the brains of vertebrates that act as a cohesive functional unit. They are situated at the base of the forebrain and are strongly connected with the cerebral cortex, thalamus and other brain areas...
. It is a large, cone-shaped mass of gray matter
Gray Matter
"Gray Matter" is a short story by Stephen King, first published in the October 1973 issue of Cavalier magazine, and later collected in King's 1978 collection Night Shift. It is set in the same area as King's novel Dreamcatcher.-Setting:...
just lateral to the internal capsule
Internal capsule
The internal capsule is an area of white matter in the brain that separates the caudate nucleus and the thalamus from the lenticular nucleus. The internal capsule contains both ascending and descending axons....
.
Etymology
The name comes from LatinLatin
Latin is an Italic language originally spoken in Latium and Ancient Rome. It, along with most European languages, is a descendant of the ancient Proto-Indo-European language. Although it is considered a dead language, a number of scholars and members of the Christian clergy speak it fluently, and...
and means lens
Lens (geometry)
In geometry, a lens is a biconvex shape comprising two circular arcs, joined at their endpoints. If the arcs have equal radii, it is called a symmetric lens.A concave-convex shape is called a lune...
-shaped, probably referring to the appearance of the nucleus from the side.
Sections and size
When divided horizontally, it exhibits, to some extent, the appearance of a biconvex lens, while a coronal section of its central part presents a somewhat triangular outline.It is shorter than the caudate nucleus and does not extend as far forward.
Boundaries
It is lateral to the caudate nucleusCaudate nucleus
The caudate nucleus is a nucleus located within the basal ganglia of the brains of many animal species. The caudate nucleus is an important part of the brain's learning and memory system.-Anatomy:...
and thalamus
Thalamus
The thalamus is a midline paired symmetrical structure within the brains of vertebrates, including humans. It is situated between the cerebral cortex and midbrain, both in terms of location and neurological connections...
, and is seen only in sections of the hemisphere.
It is bounded laterally by a lamina of white substance called the external capsule
External capsule
The external capsule is a series of white matter fiber tracts in the brain. These fibers run between the most lateral segment of the lentiform nucleus and the claustrum....
, and lateral to this is a thin layer of gray substance termed the claustrum
Claustrum
The claustrum, which is suspected to be present in all mammals, is a fairly thin vertical curved sheet of subcortical gray matter...
.
Its anterior end is continuous with the lower part of the head of the caudate nucleus
Caudate nucleus
The caudate nucleus is a nucleus located within the basal ganglia of the brains of many animal species. The caudate nucleus is an important part of the brain's learning and memory system.-Anatomy:...
and with the anterior perforated substance
Anterior perforated substance
The anterior perforated substance is an irregularly quadrilateral area in front of the optic tract and behind the olfactory trigone, from which it is separated by the fissure prima; medially and in front, it is continuous with the subcallosal gyrus; it is bounded laterally by the lateral stria of...
.
Components
In a coronal section through the middle of the lentiform nucleus, two medullary laminæ are seen dividing it into three parts.The lateral and largest part is of a reddish color, and is known as the putamen
Putamen
The putamen is a round structure located at the base of the forebrain . The putamen and caudate nucleus together form the dorsal striatum. It is also one of the structures that comprises the basal ganglia. Through various pathways, the putamen is connected to the substantia nigra and globus pallidus...
, while the medial and intermediate are of a yellowish tint, and together constitute the globus pallidus
Globus pallidus
The globus pallidus also known as paleostriatum, is a sub-cortical structure of the brain. Topographically, it is part of the telencephalon, but retains close functional ties with the subthalamus - both of which are part of the extrapyramidal motor system...
; all three are marked by fine radiating white fibers, which are most distinct in the putamen.