The lentiform nucleus (or lentiform complex, lenticular nucleus, or lenticular complex) are the

putamen The putamen (; from Latin, meaning "nutshell") is a subcortical nucleus (neuroanatomy), nucleus with a rounded structure, in the basal ganglia nuclear group. It is located at the base of the forebrain and above the midbrain. The putamen and c ...

(laterally) and the

globus pallidus The globus pallidus (GP), also known as paleostriatum or dorsal pallidum, is a major component of the Cerebral cortex, subcortical basal ganglia in the brain. It consists of two adjacent segments, one external (or lateral), known in rodents simpl ...

(medially), collectively. Due to their proximity, these two structures were formerly considered one, however, the two are separated by a thin layer of

white matter White matter refers to areas of the central nervous system that are mainly made up of myelinated axons, also called Nerve tract, tracts. Long thought to be passive tissue, white matter affects learning and brain functions, modulating the distr ...

—the external medullary lamina—and are functionally and connectionally distinct. The lentiform nucleus is a large, lens-shaped mass of gray matter just lateral to the

internal capsule The internal capsule is a paired white matter structure, as a two-way nerve tract, tract, carrying afferent nerve fiber, ascending and efferent nerve fiber, descending axon, fibers, to and from the cerebral cortex. The internal capsule is situate ...

. It forms part of the

basal ganglia The basal ganglia (BG) or basal nuclei are a group of subcortical Nucleus (neuroanatomy), nuclei found in the brains of vertebrates. In humans and other primates, differences exist, primarily in the division of the globus pallidus into externa ...

. With the

caudate nucleus The caudate nucleus is one of the structures that make up the corpus striatum, which is part of the basal ganglia in the human brain. Although the caudate nucleus has long been associated with motor processes because of its relation to Parkinso ...

, it forms the

dorsal striatum The striatum (: striata) or corpus striatum is a cluster of interconnected nuclei that make up the largest structure of the subcortical basal ganglia. The striatum is a critical component of the motor and reward systems; receives glutamater ...

Structure

When divided horizontally, it exhibits, to some extent, the appearance of a biconvex lens, while a

coronal section The dorsal plane (also known as the coronal plane or frontal plane, especially in human anatomy) is an anatomical plane that divides the body into dorsal and ventral sections. It is perpendicular to the sagittal and transverse planes. Human an ...

of its central part presents a somewhat triangular outline. It is shorter than the caudate nucleus and does not extend as far forward.

Relations

It is deep/medial to the

insular cortex The insular cortex (also insula and insular lobe) is a portion of the cerebral cortex folded deep within the lateral sulcus (the fissure separating the temporal lobe from the parietal lobe, parietal and frontal lobes) within each brain hemisphere ...

, with which it is coextensive; the two are separated by intervening structures. It is lateral to the caudate nucleus and

thalamus The thalamus (: thalami; from Greek language, Greek Wikt:θάλαμος, θάλαμος, "chamber") is a large mass of gray matter on the lateral wall of the third ventricle forming the wikt:dorsal, dorsal part of the diencephalon (a division of ...

, and is seen only in sections of the hemisphere. It is bounded laterally by a lamina of a 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. Inferiorly, there is a groove upon the surface of the lenticular nucleus that accommodates the

anterior commissure The anterior commissure (also known as the precommissure) is a white matter nerve tract, tract (a bundle of axons) connecting the two temporal lobes of the cerebral hemispheres across the midline, and placed in front of the columns of the Fornix o ...

Components

In a coronal section through the middle of the lentiform nucleus, two medullary laminae are seen dividing it into three parts. The lateral and largest part is of a reddish color, and is known as the

, while the medial and intermediate are of a yellowish tint, and together constitute the

; all three are marked by fine radiating white fibers, which are most distinct in the putamen.

Pathology

Increased volume of the lentiform nuclei has been observed in

obsessive–compulsive disorder Obsessive–compulsive disorder (OCD) is a mental disorder in which an individual has intrusive thoughts (an ''obsession'') and feels the need to perform certain routines (''Compulsive behavior, compulsions'') repeatedly to relieve the dis ...

, with decreased volume conversely observed in other anxiety disorders. The lentiform nucleus is involved in the pathology of Wilson's disease as it is one of the neuroanatomical locations of copper deposition.

Etymology

The name comes from

Latin Latin ( or ) is a classical language belonging to the Italic languages, Italic branch of the Indo-European languages. Latin was originally spoken by the Latins (Italic tribe), Latins in Latium (now known as Lazio), the lower Tiber area aroun ...

and means

lens A lens is a transmissive optical device that focuses or disperses a light beam by means of refraction. A simple lens consists of a single piece of transparent material, while a compound lens consists of several simple lenses (''elements'') ...

-shaped, probably referring to the appearance of the nucleus from the side.

Gallery

File:Gray678.png, Schematic representation of the chief ganglionic categories (I to V) File:Gray683.png, Dissection of brain-stem. Lateral view. File:Gray689.png, Superficial dissection of brain-stem. Ventral view. File:Gray710.png, Transverse section through mid-brain File:Gray730.png, Section of brain showing upper surface of temporal lobe File:Gray717.png, Coronal section of brain immediately in front of pons File:Gray743.png, Coronal section through anterior cornua of lateral ventricles File:Slide2GRE.JPG, Ventricles of brain and basal ganglia. Superior view. Horizontal section. Deep dissection. File:Slide3GRE.JPG, Ventricles of brain and basal ganglia. Superior view. Horizontal section. Deep dissection.

References

External links

* {{Authority control Basal ganglia