The cerebellar vermis (from

Latin Latin (, or , ) is a classical language belonging to the Italic branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through the power of the ...

''vermis,'' "worm") is located in the medial, cortico-nuclear zone of the

cerebellum The cerebellum (Latin for "little brain") is a major feature of the hindbrain of all vertebrates. Although usually smaller than the cerebrum, in some animals such as the mormyrid fishes it may be as large as or even larger. In humans, the cerebel ...

, which is in the posterior fossa of the

cranium The skull is a bone protective cavity for the brain. The skull is composed of four types of bone i.e., cranial bones, facial bones, ear ossicles and hyoid bone. However two parts are more prominent: the cranium and the mandible. In humans, the ...

. The primary fissure in the vermis curves

ventrolateral Standard anatomical terms of location are used to unambiguously describe the anatomy of animals, including humans. The terms, typically derived from Latin or Greek roots, describe something in its standard anatomical position. This position prov ...

ly to the

superior Superior may refer to: *Superior (hierarchy), something which is higher in a hierarchical structure of any kind Places *Superior (proposed U.S. state), an unsuccessful proposal for the Upper Peninsula of Michigan to form a separate state *Lake ...

surface of the

, dividing it into

anterior Standard anatomical terms of location are used to unambiguously describe the anatomy of animals, including humans. The terms, typically derived from Latin or Greek roots, describe something in its standard anatomical position. This position prov ...

and posterior lobes. Functionally, the vermis is associated with bodily posture and locomotion. The vermis is included within the

spinocerebellum The anatomy of the cerebellum can be viewed at three levels. At the level of gross anatomy, the cerebellum consists of a tightly folded and crumpled layer of cortex, with white matter underneath, several deep nuclei embedded in the white matte ...

and receives somatic sensory input from the

head A head is the part of an organism which usually includes the ears, brain, forehead, cheeks, chin, eyes, nose, and mouth, each of which aid in various sensory functions such as sight, hearing, smell, and taste. Some very simple animals may ...

and proximal body parts via ascending spinal pathways. The

develops in a rostro-caudal manner, with

rostral Rostral may refer to: Anatomy * Rostral (anatomical term), situated toward the oral or nasal region * Rostral bone, in ceratopsian dinosaurs * Rostral organ, of certain fish * Rostral scale, in snakes and scaled reptiles Other uses * Rostral colu ...

regions in the midline giving rise to the vermis, and

caudal Caudal may refer to: Anatomy * Caudal (anatomical term) (from Latin ''cauda''; tail), used to describe how close something is to the trailing end of an organism * Caudal artery, the portion of the dorsal aorta of a vertebrate that passes into the ...

regions developing into the

cerebellar hemispheres The cerebellum consists of three parts, a median and two lateral, which are continuous with each other, and are substantially the same in structure. The median portion is constricted, and is called the vermis, from its annulated appearance which ...

. By 4 months of

prenatal development Prenatal development () includes the development of the embryo and of the fetus during a viviparous animal's gestation. Prenatal development starts with fertilization, in the germinal stage of embryonic development, and continues in fetal devel ...

, the vermis becomes fully foliated, while development of the hemispheres lags by 30–60 days. Postnatally,

proliferation Proliferation may refer to: Weapons *Nuclear proliferation, the spread of nuclear weapons, material, and technology *Chemical weapon proliferation, the spread of chemical weapons, material, and technology * Small arms proliferation, the spread of ...

and organization of the cellular components of the

continues, with completion of the foliation pattern by 7 months of life and final migration, proliferation, and arborization of cerebellar neurons by 20 months. Inspection of the posterior fossa is a common feature of prenatal ultrasound and is used primarily to determine whether excess fluid or malformations of the cerebellum exist. Anomalies of the cerebellar vermis are diagnosed in this manner and include

phenotypes In genetics, the phenotype () is the set of observable characteristics or traits of an organism. The term covers the organism's morphology or physical form and structure, its developmental processes, its biochemical and physiological proper ...

consistent with Dandy–Walker malformation, rhombencephalosynapsis, displaying no vermis with fusion of the

, pontocerebellar hypoplasia, or stunted growth of the cerebellum, and neoplasms. In neonates, hypoxic injury to the cerebellum is fairly common, resulting in neuronal loss and

gliosis Gliosis is a nonspecific reactive change of glial cells in response to damage to the central nervous system (CNS). In most cases, gliosis involves the proliferation or hypertrophy of several different types of glial cells, including astrocytes, ...

. Symptoms of these disorders range from mild loss of fine

motor control Motor control is the regulation of movement in organisms that possess a nervous system. Motor control includes reflexes as well as directed movement. To control movement, the nervous system must integrate multimodal sensory information (both f ...

to severe mental retardation and

death Death is the irreversible cessation of all biological functions that sustain an organism. For organisms with a brain, death can also be defined as the irreversible cessation of functioning of the whole brain, including brainstem, and brain ...

. Karyotyping has shown that most

pathologies Pathology is the study of the causes and effects of disease or injury. The word ''pathology'' also refers to the study of disease in general, incorporating a wide range of biology research fields and medical practices. However, when used in t ...

associated with the vermis are inherited though an

autosomal recessive In genetics, dominance is the phenomenon of one variant (allele) of a gene on a chromosome masking or overriding the effect of a different variant of the same gene on the other copy of the chromosome. The first variant is termed dominant and t ...

pattern, with most known

mutations In biology, a mutation is an alteration in the nucleic acid sequence of the genome of an organism, virus, or extrachromosomal DNA. Viral genomes contain either DNA or RNA. Mutations result from errors during DNA or viral replication, mi ...

occurring on the

X chromosome The X chromosome is one of the two sex-determining chromosomes (allosomes) in many organisms, including mammals (the other is the Y chromosome), and is found in both males and females. It is a part of the XY sex-determination system and XO sex-d ...

. The vermis is intimately associated with all regions of the cerebellar cortex, which can be divided into three functional parts, each having distinct connections with the brain and

spinal cord The spinal cord is a long, thin, tubular structure made up of nervous tissue, which extends from the medulla oblongata in the brainstem to the lumbar region of the vertebral column (backbone). The backbone encloses the central canal of the spi ...

. These regions are the

vestibulocerebellum The anatomy of the cerebellum can be viewed at three levels. At the level of gross anatomy, the cerebellum consists of a tightly folded and crumpled layer of cortex, with white matter underneath, several deep nuclei embedded in the white matte ...

, which is responsible primarily for the control of eye movements; the

, involved in fine tune body and limb movement; and the

cerebrocerebellum The anatomy of the cerebellum can be viewed at three levels. At the level of gross anatomy, the cerebellum consists of a tightly folded and crumpled layer of cortex, with white matter underneath, several deep nuclei embedded in the white matter ...

, which is associated with planning, initiation and timing of movements.

Structure

The vermis is the unpaired, median portion of the cerebellum that connects the two hemispheres. Both the vermis and the hemispheres are composed of

lobules In anatomy, a lobe is a clear anatomical division or extension of an organ (as seen for example in the brain, lung, liver, or kidney) that can be determined without the use of a microscope at the gross anatomy level. This is in contrast to the mu ...

formed by groups of folia. There are nine lobules of the vermis: lingula, central lobule, culmen, clivus, folium of the vermis, tuber, pyramid, uvula and nodule. These lobules are often difficult to observe during human anatomy classes and may vary in size, shape and number of folia. It has been shown that folia of the cerebellum exhibit frequent variations in form, number and arrangement between individuals.

Lobe anatomy

The lingula is the first lobule of the upper portion of the vermis on the superoinferior axis and pertains to the

paleocerebellum The cerebellum (Latin for "little brain") is a major feature of the hindbrain of all vertebrates. Although usually smaller than the cerebrum, in some animals such as the mormyrid fishes it may be as large as or even larger. In humans, the cerebel ...

together with the central lobule, culmen, pyramid and uvula. It is separated from the central lobule by the pre-central

fissure A fissure is a long, narrow crack opening along the surface of Earth. The term is derived from the Latin word , which means 'cleft' or 'crack'. Fissures emerge in Earth's crust, on ice sheets and glaciers, and on volcanoes. Ground fissure A ...

. The central lobule is the second lobule of the upper portion of the vermis on the superoinferior axis. The culmen is the third and largest lobule of the upper portion of the vermis on the superoinferior axis. It is separated from the declive by the primary fissure and is related with the

quadrangular lobule of the hemisphere. The pyramid is the seventh lobule of the vermis on the superoinferior axis. It is separated from the tuber and uvula by the pre-pyramidal and secondary fissures, respectively. This lobule is related with the biventral lobule of the hemisphere. The uvula is the second largest lobule, following the culmen. It pertains to the paleocerebellum and is separated from the nodule by the posterolateral fissure.

Spinocerebellum

The spinocerebellum receives proprioception input from the dorsal columns of the

(including the

spinocerebellar tract The spinocerebellar tract is a nerve tract originating in the spinal cord and terminating in the same side (ipsilateral) of the cerebellum. Origins of proprioceptive information Proprioceptive information is obtained by Golgi tendon organs and mu ...

) and from the

trigeminal nerve In neuroanatomy, the trigeminal nerve ( lit. ''triplet'' nerve), also known as the fifth cranial nerve, cranial nerve V, or simply CN V, is a cranial nerve responsible for sensation in the face and motor functions such as biting and chewin ...

, as well as from visual and auditory systems. It sends fibers to deep cerebellar nuclei that, in turn, project to both the cerebral cortex and the brain stem, thus providing modulation of descending motor systems. This region comprises the vermis and intermediate parts of the cerebellar hemispheres. Sensory information from the periphery and from the primary motor and somatosensory cortex terminate in this region. Purkinje cells of the vermis project to the fastigial nucleus, controlling the

axial Axial may refer to: * one of the anatomical directions describing relationships in an animal body * In geometry: :* a geometric term of location :* an axis of rotation * In chemistry, referring to an axial bond * a type of modal frame, in music * ...

and

proximal Standard anatomical terms of location are used to unambiguously describe the anatomy of animals, including humans. The terms, typically derived from Latin or Greek roots, describe something in its standard anatomical position. This position pro ...

musculature involved in the execution of limb movements. Purkinje cells in the intermediate zone of the spinocerebellum project to the interposed nuclei, which control the distal musculature components of the descending motor pathways needed for limb movement. Both of these nuclei include projections to the motor cortex in the cerebrum.

Nuclei

The interposed nucleus is smaller than the

dentate nucleus The dentate nucleus is a cluster of neurons, or nerve cells, in the central nervous system that has a dentate – tooth-like or serrated – edge. It is located within the deep white matter of each cerebellar hemisphere, and it is the largest si ...

but larger than the fastigial nucleus and functions to modulate muscle stretch reflexes of distal musculature. It is located dorsal to the fourth ventricle and lateral to the fastigial nucleus; it receives

afferent Afferent may refer to: Anatomical structures Meaning "conveying towards a center": * Afferent arterioles, blood vessels that supply the nephrons * Afferent lymphatic vessels, lymph vessels that carry lymph to a lymph node * Afferent nerve fiber ...

neuronal supply from the

anterior lobe The anterior lobe of cerebellum is the portion of the cerebellum responsible for mediating unconscious proprioception. Inputs into the anterior lobe of the cerebellum are mainly from the spinal cord. It is sometimes equated to the "paleocerebellu ...

of the cerebellum and sends output via the

superior cerebellar peduncle In the human brain, the superior cerebellar peduncle (brachium conjunctivum) is a paired structure of white matter that connects the cerebellum to the midbrain. It consists mainly of efferent fibers, the cerebellothalamic tract that runs from a cer ...

and the

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 fastigial nucleus is the most medial

efferent Efferent may refer to: Anatomical structures Meaning 'conveying away from a center': *Efferent arterioles, conveying blood away from the Bowman's capsule in the kidney *Efferent nerve fiber, carries nerve impulses away from the central nervous sy ...

cerebellar nucleus, targeting the pontine and medullary

reticular formation The reticular formation is a set of interconnected nuclei that are located throughout the brainstem. It is not anatomically well defined, because it includes neurons located in different parts of the brain. The neurons of the reticular formation ...

as well as the

vestibular nuclei The vestibular nuclei (VN) are the cranial nuclei for the vestibular nerve located in the brainstem. In Terminologia Anatomica they are grouped in both the pons and the medulla in the brainstem. Structure Path The fibers of the vestibular nerve ...

. This region deals with antigravity muscle groups and other synergies involved with standing and walking. It is thought that fastigial nuclei

axons An axon (from Greek ἄξων ''áxōn'', axis), or nerve fiber (or nerve fibre: see American and British English spelling differences#-re, -er, spelling differences), is a long, slender projection of a nerve cell, or neuron, in vertebrates, th ...

are

excitatory In neuroscience, an excitatory postsynaptic potential (EPSP) is a postsynaptic potential that makes the postsynaptic neuron more likely to fire an action potential. This temporary depolarization of postsynaptic membrane potential, caused by the ...

and project beyond the

, likely using

glutamate Glutamic acid (symbol Glu or E; the ionic form is known as glutamate) is an α-amino acid that is used by almost all living beings in the biosynthesis of proteins. It is a non-essential nutrient for humans, meaning that the human body can syn ...

and

aspartate Aspartic acid (symbol Asp or D; the ionic form is known as aspartate), is an α-amino acid that is used in the biosynthesis of proteins. Like all other amino acids, it contains an amino group and a carboxylic acid. Its α-amino group is in the pro ...

as neurotransmitters.

Pathology

Malformations A birth defect, also known as a congenital disorder, is an abnormal condition that is present at childbirth, birth regardless of its cause. Birth defects may result in disability, disabilities that may be physical disability, physical, intellect ...

of the posterior fossa have been recognized more frequently during the past few decades as the result of recent advances in technology. Malformations of the cerebellar vermis were first identified using

pneumoencephalography Pneumoencephalography (sometimes abbreviated PEG; also referred to as an "air study") was a common medical procedure in which most of the cerebrospinal fluid (CSF) was drained from around the brain by means of a lumbar puncture and replaced with ai ...

, where air is injected into the cerebrospinal fluid spaces of the

; displaced, occluded or

dysplastic Dysplasia is any of various types of abnormal growth or development of cells (microscopic scale) or organs (macroscopic scale), and the abnormal histology or anatomical structure(s) resulting from such growth. Dysplasias on a mainly microscopic ...

structures could be identified. Upon the advent of

computerized tomography A computed tomography scan (CT scan; formerly called computed axial tomography scan or CAT scan) is a medical imaging technique used to obtain detailed internal images of the body. The personnel that perform CT scans are called radiographers ...

(CT) and

magnetic resonance imaging Magnetic resonance imaging (MRI) is a medical imaging technique used in radiology to form pictures of the anatomy and the physiological processes of the body. MRI scanners use strong magnetic fields, magnetic field gradients, and radio wave ...

(MRI), the resolution of cranial structures including the mid-hindbrain regions improved dramatically.

Joubert syndrome

Joubert syndrome Joubert syndrome is a rare autosomal recessive genetic disorder that affects the cerebellum, an area of the brain that controls balance and coordination. Joubert syndrome is one of the many genetic syndromes associated with syndromic retinitis pig ...

(JS) is one of the most commonly diagnosed syndromes associated with the molar tooth sign (MTS), or

hypoplasia Hypoplasia (from Ancient Greek ὑπo- ''hypo-'' 'under' + πλάσις ''plasis'' 'formation'; adjective form ''hypoplastic'') is underdevelopment or incomplete development of a tissue or organ.JS is defined clinically by features of

hypotonia Hypotonia is a state of low muscle tone (the amount of tension or resistance to stretch in a muscle), often involving reduced muscle strength. Hypotonia is not a specific medical disorder, but a potential manifestation of many different diseases a ...

infancy An infant or baby is the very young offspring of human beings. ''Infant'' (from the Latin word ''infans'', meaning 'unable to speak' or 'speechless') is a formal or specialised synonym for the common term ''baby''. The terms may also be used to ...

with later development of ataxia, developmental delays, mental retardation, abnormal breathing patterns, abnormal eye movements specific to oculomotor apraxia, or the presence of the MTS on the cranial MRI. JS is an

condition with an estimated prevalence of 1: 100,000.

Dandy Walker malformation

Dandy Walker malformation A dandy is a man who places particular importance upon physical appearance, refined language, and leisurely hobbies, pursued with the appearance of nonchalance. A dandy could be a self-made man who strove to imitate an aristocratic lifestyle desp ...

is a relatively common

congenital A birth defect, also known as a congenital disorder, is an abnormal condition that is present at birth regardless of its cause. Birth defects may result in disabilities that may be physical, intellectual, or developmental. The disabilities can ...

brain malformation with a prevalence of 1:30,000 live births. Dandy Walker malformation is characterized by enlarged posterior fossa and in which the cerebellar vermis is completely absent, or present in a rudimentary form, sometimes rotated accompanied by an elevation of the fourth ventricle. It is also commonly associated with dysplasias of

brainstem The brainstem (or brain stem) is the posterior stalk-like part of the brain that connects the cerebrum with the spinal cord. In the human brain the brainstem is composed of the midbrain, the pons, and the medulla oblongata. The midbrain is cont ...

nuclei. DWM has been reported to be in association with a wide array of

chromosomal A chromosome is a long DNA molecule with part or all of the genetic material of an organism. In most chromosomes the very long thin DNA fibers are coated with packaging proteins; in eukaryotic cells the most important of these proteins are ...

anomalies, including trisomy 18, trisomy 9, and trisomy 13. Surveys suggest that

prenatal Prenatal development () includes the development of the embryo and of the fetus during a viviparous animal's gestation. Prenatal development starts with fertilization, in the germinal stage of embryonic development, and continues in fetal devel ...

exposure to teratogens such as

rubella Rubella, also known as German measles or three-day measles, is an infection caused by the rubella virus. This disease is often mild, with half of people not realizing that they are infected. A rash may start around two weeks after exposure and ...

alcohol Alcohol most commonly refers to: * Alcohol (chemistry), an organic compound in which a hydroxyl group is bound to a carbon atom * Alcohol (drug), an intoxicant found in alcoholic drinks Alcohol may also refer to: Chemicals * Ethanol, one of sev ...

are correlated with development of Dandy Walker malformation.

Rhombencephalosynapsis

Rhombencephalosynapsis is an anomaly characterized by the absence or severe dysgenesis of the cerebellar vermis with fusion of the

, peduncles, and dentate nuclei. Diagnostic features include fusion of the midbrain colliculi,

hydrocephalus Hydrocephalus is a condition in which an accumulation of cerebrospinal fluid (CSF) occurs within the brain. This typically causes increased intracranial pressure, pressure inside the skull. Older people may have headaches, double vision, poor ...

, absence of the corpus callosum other midline structural brain malformations.

Damage

Lesions to the vermis commonly give rise to clinical depression, inappropriate emotional displays (e.g. unwarranted giggling) in addition to movement disorders.

Comparative anatomy

Early neurophysiologists suggest that

retina The retina (from la, rete "net") is the innermost, light-sensitive layer of tissue of the eye of most vertebrates and some molluscs. The optics of the eye create a focused two-dimensional image of the visual world on the retina, which then ...

l and inertial signals were selected for about 450 million years ago by primitive

-cerebellar circuitry because of their relationship with the environment. Microscopically, it is evident that Purkinje cell precursors arose from

granule cells A granule is a large particle or grain. It can refer to: * Granule (cell biology), any of several submicroscopic structures, some with explicable origins, others noted only as cell type-specific features of unknown function ** Azurophilic granul ...

, first forming in irregular patterns, then progressively becoming organized in a layered fashion. Evolutionarily, the Purkinje cells then developed extensive dendritic trees that increasingly became confined to a single plane, through which the

of granule cells threaded, eventually forming a neuronal grid of right angles. The origin of the

is in close association with that of the nuclei of the vestibular cranial nerve and lateral line nerves, perhaps suggesting that this part of the cerebellum originated as a means of carrying out transformations of the

coordinate system In geometry, a coordinate system is a system that uses one or more numbers, or coordinates, to uniquely determine the position of the points or other geometric elements on a manifold such as Euclidean space. The order of the coordinates is sig ...

from input data of the

vestibular organ The vestibular system, in vertebrates, is a sensory system that creates the sense of balance and spatial orientation for the purpose of coordinating movement with balance. Together with the cochlea, a part of the auditory system, it constitutes ...

and the lateral line organs. This suggests that the function of the cerebellum

evolved Evolution is change in the heritable characteristics of biological populations over successive generations. These characteristics are the expressions of genes, which are passed on from parent to offspring during reproduction. Variation t ...

as a mode of computing and representing an image relating to the position of the body in space. The cerebellar vermis evolved in conjunction with the hemispheres; this is seen in lampreys and higher

vertebrates Vertebrates () comprise all animal taxa within the subphylum Vertebrata () ( chordates with backbones), including all mammals, birds, reptiles, amphibians, and fish. Vertebrates represent the overwhelming majority of the phylum Chordata, ...

In fish

, the cerebellar vermis develops between two bilaterally symmetrical formations located dorsal to the upper end of the

medulla oblongata The medulla oblongata or simply medulla is a long stem-like structure which makes up the lower part of the brainstem. It is anterior and partially inferior to the cerebellum. It is a cone-shaped neuronal mass responsible for autonomic (involun ...

, or rhombencephalon. This is the region of termination for the

fibers Fiber or fibre (from la, fibra, links=no) is a natural or artificial substance that is significantly longer than it is wide. Fibers are often used in the manufacture of other materials. The strongest engineering materials often incorporate ...

of the vestibular nerve and lateral line nerves; thus, these are the oldest

paths to the cerebellum and cerebellar vermis. In bony fish, or teleosts, it has been proposed that the cerebellar auricles, which receive a large amount of input from the vestibulolateral line system, constitute the

and are homologues of the flocculonodular lobe of higher vertebrates along with the corpus cerebelli, which receives spinocerebellar and tectocerebellar fibers. The

labyrinth In Greek mythology, the Labyrinth (, ) was an elaborate, confusing structure designed and built by the legendary artificer Daedalus for King Minos of Crete at Knossos. Its function was to hold the Minotaur, the monster eventually killed by the ...

and the lateral line organs of lampreys have structural and functional similarity. An important difference between the two structures is that the arrangement of the lateral line organs are such that they are sensitive to relative motion of the fluid surrounding the animal, whereas the labyrinths, having very similar sensing mechanisms, are sensitive to endolymph, providing information concerning the animal's own equilibrium of the body and orientation in space.

Additional images

File:Vermis and paravermis by Sanjoy Sanyal.webm, Dissection video. Explains the position of vermis. File:Cerebellar vermis --- animation.gif, Animation. Vermis is highlighted in red. File:Slide2BRA.JPG, Brainstem. Posterior view. File:Human brain midsagittal view description.JPG, Midsagittal view File:CerebellumDiv.png, Schematic representation of the major anatomical subdivisions of the cerebellum.

References

External links

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at University of Texas Southwestern Medical Center at Dallas
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