Cytoarchitectonics of the cerebral cortex
Encyclopedia
The cytoarchitectonics of the cerebral cortex is the study of neuron
al cell bodies
cytoarchitecture in the cerebral cortex
of the brain
.
, topography, receptor-binding autoradiography, immunohistochemistry
, etc.), by obtaining sections of the brain and staining them with chemical agents that reveal how nerve cell bodies (or neurons) are "stacked" into layers. The study of the parcellation of nerve fibers (primarily axons) into layers forms the subject of myeloarchitectonics (μυελός=marrow + αρχιτεκτονική=architecture), an approach complementary to cytoarchitectonics.
The birth of the cytoarchitectonics of the human cerebral cortex
is credited to the Viennese psychiatrist Theodor Meynert
(1833-1892), who in 1867 noticed regional variations in the histological structure of different parts of the gray matter in the cerebral hemispheres. Other brain scientists who subsequently contributed further classic studies on cortical cytoarchitectonics are:
the neuroscientist and histologist who originated the technique) is commonly used for determining the cytoarchitectonics of neuroanatomical structures, using common agents such as thionin
, cresyl violet
, or neutral red
. These dyes intensely stain "Nissl bodies" (rough endoplasmic reticulum), which are abundant in neurons and reveal specific patterns of cytoarchitecture in the brain. Other common staining techniques used by histologists in other tissues (such as the hematoxylin and eosin or "H&E stain
") leave brain tissue appearing largely homogenous and do not reveal the level of organization apparent in a Nissl stain. Nissl staining reveals details ranging from the macroscopic, such as the laminar pattern of the cerebral cortex or the interlocking nuclear patterns of the diencephalon and brainstem, to the microscopic, such as the distinctions between individual neurons and glia in any subregion of the central nervous system. Many other neuroanatomic and cytoarchitectonic techniques are available to supplement Nissl cytoarchitectonics, including immunohistochemistry
and in situ hybridization
, which allow one to label any gene
or protein
expressed in any group of cells in the brain. However, Nissl cytoarchitecture remains a reliable, inexpensive, and familiar starting or reference point for neuroscientists wishing to examine or communicate their findings in a widely recognized anatomical framework and/or in reference to neuroanatomical atlases which use the same technique.
Neuron
A neuron is an electrically excitable cell that processes and transmits information by electrical and chemical signaling. Chemical signaling occurs via synapses, specialized connections with other cells. Neurons connect to each other to form networks. Neurons are the core components of the nervous...
al cell bodies
Soma (biology)
The soma , or perikaryon , or cyton, is the bulbous end of a neuron, containing the cell nucleus. The word "soma" comes from the Greek σῶμα, meaning "body"; the soma of a neuron is often called the "cell body"...
cytoarchitecture in the cerebral cortex
Cerebral cortex
The cerebral cortex is a sheet of neural tissue that is outermost to the cerebrum of the mammalian brain. It plays a key role in memory, attention, perceptual awareness, thought, language, and consciousness. It is constituted of up to six horizontal layers, each of which has a different...
of the brain
Brain
The brain is the center of the nervous system in all vertebrate and most invertebrate animals—only a few primitive invertebrates such as sponges, jellyfish, sea squirts and starfishes do not have one. It is located in the head, usually close to primary sensory apparatus such as vision, hearing,...
.
History
Originally implemented by the school of Wernike the practice used varying cell structure and organization into layers to define functional regions in the cortex. Applied particularly to the study of the central nervous system, cytoarchitectonics is one of the ways to parse the brain (along with gross anatomyGross anatomy
Gross anatomy is the study of anatomy at the macroscopic level. The term gross distinguishes it from other areas of anatomical study, including microscopic anatomy, which is studied on a microscopic scale, typically with a microscope....
, topography, receptor-binding autoradiography, immunohistochemistry
Immunohistochemistry
Immunohistochemistry or IHC refers to the process of detecting antigens in cells of a tissue section by exploiting the principle of antibodies binding specifically to antigens in biological tissues. IHC takes its name from the roots "immuno," in reference to antibodies used in the procedure, and...
, etc.), by obtaining sections of the brain and staining them with chemical agents that reveal how nerve cell bodies (or neurons) are "stacked" into layers. The study of the parcellation of nerve fibers (primarily axons) into layers forms the subject of myeloarchitectonics (
The birth of the cytoarchitectonics of the human cerebral cortex
Human brain
The human brain has the same general structure as the brains of other mammals, but is over three times larger than the brain of a typical mammal with an equivalent body size. Estimates for the number of neurons in the human brain range from 80 to 120 billion...
is credited to the Viennese psychiatrist Theodor Meynert
Theodor Meynert
Theodor Hermann Meynert was a German-Austrian neuropathologist and anatomist who was born in Dresden.In 1861 he earned his medical doctorate, and in 1875 became director of the psychiatric clinic associated with the University of Vienna. One of his better known students in Vienna was Sigmund...
(1833-1892), who in 1867 noticed regional variations in the histological structure of different parts of the gray matter in the cerebral hemispheres. Other brain scientists who subsequently contributed further classic studies on cortical cytoarchitectonics are:
- Alfred Walter CampbellAlfred Walter Campbell-Further reading:...
(1868-1937), an Englishman who presented a system of cortical parcellation into 14 areas. - Sir Grafton Elliot SmithGrafton Elliot SmithSir Grafton Elliot Smith, FRS FRCP was an Australian anatomist and a proponent of the hyperdiffusionist view of prehistory.-Professional career:Smith was born in Grafton, New South Wales...
(1871-1937), a New South Wales native working in Cairo, with observations identifying 50 areas; - Korbinian BrodmannKorbinian BrodmannKorbinian Brodmann was a German neurologist who became famous for his definition of the cerebral cortex into 52 distinct regions from their cytoarchitectonic characteristics.-Life:...
(1868-1918) in Berlin, working on the brains of diverse mammalian species and developing a division of the cerebral cortex into 52 discrete areas (of which 44 in the human, and the remaining 8 in non-human primate brain); - Constantin von EconomoConstantin von EconomoConstantin Freiherr von Economo was a Romanian psychiatrist and neurologist of Greek origin. He is mostly known for his discovery of encephalitis lethargica and his atlas of cytoarchitectonics.- Youth and schooling :Constantin Freiherr Economo von San Serff was born in Brăila, Romania, to Greek...
(1876-1931) and Georg N. KoskinasGeorg N. KoskinasGeorg N. Koskinas was a Greek neurologist-psychiatrist. He was born on December 1, 1885 in Geraki, near Sparta. He studied medicine at the University of Athens, graduating in 1910, and subsequently trained as a resident in the Clinic of Psychiatry and Neurology of Aiginiteion Hospital under Michel...
(1885-1975), two neurologists in Vienna who produced a landmark work in brain research by defining 107 cortical areas on the basis of cytoarchitectonic criteria.
Nissl staining
The Nissl staining technique (named for Franz NisslFranz Nissl
Franz Nissl was a German medical researcher. He was a noted neuropathologist.-Early life:...
the neuroscientist and histologist who originated the technique) is commonly used for determining the cytoarchitectonics of neuroanatomical structures, using common agents such as thionin
Thionin
Thionine, also known as thionine acetate or Lauth's violet, is a strongly staining metachromatic dye that are widely used for biological staining. Thionine can also be used in place of Schiff reagent in quantitative Feulgen staining of DNA. It can also be used to mediate electron transfer in...
, cresyl violet
Cresyl violet
Cresyl violet is an organic compound with the chemical formula C19H18ClN3O. It is used in biology and medicine as a histological stain. Cresyl violet is an effective and reliable stain used for light microscopy sections. Initially, tissue sections are ‘defatted’ by passing through graded dilutions...
, or neutral red
Neutral red
Neutral Red is a eurhodin dye used for staining in histology. It stains lysosomes red. It is used as a general stain in histology, as a counterstain in combination with other dyes, and for many staining methods. Together with Janus Green B, it is used to stain embryonal tissues and supravital...
. These dyes intensely stain "Nissl bodies" (rough endoplasmic reticulum), which are abundant in neurons and reveal specific patterns of cytoarchitecture in the brain. Other common staining techniques used by histologists in other tissues (such as the hematoxylin and eosin or "H&E stain
H&E stain
H&E stain, HE stain or hematoxylin and eosin stain is a popular staining method in histology. It is the most widely used stain in medical diagnosis; for example when a pathologist looks at a biopsy of a suspected cancer, the histological section is likely to be stained with H&E and termed H&E...
") leave brain tissue appearing largely homogenous and do not reveal the level of organization apparent in a Nissl stain. Nissl staining reveals details ranging from the macroscopic, such as the laminar pattern of the cerebral cortex or the interlocking nuclear patterns of the diencephalon and brainstem, to the microscopic, such as the distinctions between individual neurons and glia in any subregion of the central nervous system. Many other neuroanatomic and cytoarchitectonic techniques are available to supplement Nissl cytoarchitectonics, including immunohistochemistry
Immunohistochemistry
Immunohistochemistry or IHC refers to the process of detecting antigens in cells of a tissue section by exploiting the principle of antibodies binding specifically to antigens in biological tissues. IHC takes its name from the roots "immuno," in reference to antibodies used in the procedure, and...
and in situ hybridization
In situ hybridization
In situ hybridization is a type of hybridization that uses a labeled complementary DNA or RNA strand to localize a specific DNA or RNA sequence in a portion or section of tissue , or, if the tissue is small enough , in the entire tissue...
, which allow one to label any gene
Gene
A gene is a molecular unit of heredity of a living organism. It is a name given to some stretches of DNA and RNA that code for a type of protein or for an RNA chain that has a function in the organism. Living beings depend on genes, as they specify all proteins and functional RNA chains...
or protein
Protein
Proteins are biochemical compounds consisting of one or more polypeptides typically folded into a globular or fibrous form, facilitating a biological function. A polypeptide is a single linear polymer chain of amino acids bonded together by peptide bonds between the carboxyl and amino groups of...
expressed in any group of cells in the brain. However, Nissl cytoarchitecture remains a reliable, inexpensive, and familiar starting or reference point for neuroscientists wishing to examine or communicate their findings in a widely recognized anatomical framework and/or in reference to neuroanatomical atlases which use the same technique.
See also
- Brodmann areas
- Theodor MeynertTheodor MeynertTheodor Hermann Meynert was a German-Austrian neuropathologist and anatomist who was born in Dresden.In 1861 he earned his medical doctorate, and in 1875 became director of the psychiatric clinic associated with the University of Vienna. One of his better known students in Vienna was Sigmund...
- Korbinian BrodmannKorbinian BrodmannKorbinian Brodmann was a German neurologist who became famous for his definition of the cerebral cortex into 52 distinct regions from their cytoarchitectonic characteristics.-Life:...
- Constantin von EconomoConstantin von EconomoConstantin Freiherr von Economo was a Romanian psychiatrist and neurologist of Greek origin. He is mostly known for his discovery of encephalitis lethargica and his atlas of cytoarchitectonics.- Youth and schooling :Constantin Freiherr Economo von San Serff was born in Brăila, Romania, to Greek...
- Georg N. KoskinasGeorg N. KoskinasGeorg N. Koskinas was a Greek neurologist-psychiatrist. He was born on December 1, 1885 in Geraki, near Sparta. He studied medicine at the University of Athens, graduating in 1910, and subsequently trained as a resident in the Clinic of Psychiatry and Neurology of Aiginiteion Hospital under Michel...