The substantia innominata also innominate substance, or substantia innominata of Meynert (Latin for unnamed substance) is a series of layers in the
human brain
The human brain is the central organ of the human nervous system, and with the spinal cord makes up the central nervous system. The brain consists of the cerebrum, the brainstem and the cerebellum. It controls most of the activities of ...
consisting partly of
gray
Grey (more common in British English) or gray (more common in American English) is an intermediate color between black and white. It is a neutral or achromatic color, meaning literally that it is "without color", because it can be compose ...
and partly of
white matter
White matter refers to areas of the central nervous system (CNS) that are mainly made up of myelinated axons, also called tracts. Long thought to be passive tissue, white matter affects learning and brain functions, modulating the distribu ...
, which lies below the anterior part of the
thalamus
The thalamus (from Greek θάλαμος, "chamber") is a large mass of gray matter located in the dorsal part of the diencephalon (a division of the forebrain). Nerve fibers project out of the thalamus to the cerebral cortex in all direct ...
and
lentiform nucleus. It is included as part of the
anterior perforated substance
The anterior perforated substance is a part of the brain. It is bilateral. It is irregular and quadrilateral. It lies in front of the optic tract and behind the olfactory trigone.
Structure
The anterior perforated substance is bilateral. It ...
(as it appears to be perforated by many holes which are actually blood vessels). It is part of the
basal forebrain structures and includes the
nucleus basalis. A portion of the substantia innominata, below the
globus pallidus is considered as part of the
extended amygdala.
Layers
It consists of three layers, superior, middle, and inferior.
* The ''superior layer'' is named the
ansa lenticularis, and its fibers, derived from the medullary lamina of the lentiform nucleus, pass medially to end in the thalamus and subthalamic region, while others are said to end in the
tegmentum
The tegmentum (from Latin for "covering") is a general area within the brainstem. The tegmentum is the ventral part of the midbrain and the tectum is the dorsal part of the midbrain. It is located between the ventricular system and distinctive ba ...
and
red nucleus
The red nucleus or nucleus ruber is a structure in the rostral midbrain involved in motor coordination. The red nucleus is pale pink, which is believed to be due to the presence of iron in at least two different forms: hemoglobin and ferritin. ...
.
* The ''middle layer'' consists of nerve cells and nerve fibers; fibers enter it from the parietal lobe through the
external capsule, while others are said to connect it with the
medial longitudinal fasciculus.
* The ''inferior layer'' forms the main part of the inferior stalk of the thalamus, and connects this body with the
temporal lobe
The temporal lobe is one of the four major lobes of the cerebral cortex in the brain of mammals. The temporal lobe is located beneath the lateral fissure on both cerebral hemispheres of the mammalian brain.
The temporal lobe is involved i ...
and the
insula.
Striatopallidal system
In the late 20th century following improved imaging by
staining
Staining is a technique used to enhance contrast in samples, generally at the microscopic level. Stains and dyes are frequently used in histology (microscopic study of biological tissues), in cytology (microscopic study of cells), and in th ...
it was reclassified as part of the
striatopallidal system, which is made up of the dorsal striatum and dorsal pallidum, and the ventral striatum and ventral pallidum.
References
External links
Diagram at biocfarm.unibo.it
{{Authority control
Rostral basal ganglia and associated structures