A phrase describing how a term should be used and/or a citation to a work which uses it. May also include other kinds of examples that facilitate immediate understanding, such as widely know prototypes or instances of a class, or cases where a relation is said to hold.
example of usage
The official definition, explaining the meaning of a class or property. Shall be Aristotelian, formalized and normalized. Can be augmented with colloquial definitions.
2012-04-05: Barry Smith The official OBI definition, explaining the meaning of a class or property: 'Shall be Aristotelian, formalized and normalized. Can be augmented with colloquial definitions' is terrible. Can you fix to something like: A statement of necessary and sufficient conditions explaining the meaning of an expression referring to a class or property. Alan Ruttenberg Your proposed definition is a reasonable candidate, except that it is very common that necessary and sufficient conditions are not given. Mostly they are necessary, occasionally they are necessary and sufficient or just sufficient. Often they use terms that are not themselves defined and so they effectively can't be evaluated by those criteria. On the specifics of the proposed definition: We don't have definitions of 'meaning' or 'expression' or 'property'. For 'reference' in the intended sense I think we use the term 'denotation'. For 'expression', I think we you mean symbol, or identifier. For 'meaning' it differs for class and property. For class we want documentation that let's the intended reader determine whether an entity is instance of the class, or not. For property we want documentation that let's the intended reader determine, given a pair of potential relata, whether the assertion that the relation holds is true. The 'intended reader' part suggests that we also specify who, we expect, would be able to understand the definition, and also generalizes over human and computer reader to include textual and logical definition. Personally, I am more comfortable weakening definition to documentation, with instructions as to what is desirable. We also have the outstanding issue of how to aim different definitions to different audiences. A clinical audience reading chebi wants a different sort of definition documentation/definition from a chemistry trained audience, and similarly there is a need for a definition that is adequate for an ontologist to work with.
definition
An administrative note intended for its editor. It may not be included in the publication version of the ontology, so it should contain nothing necessary for end users to understand the ontology.
editor note
Relates an annotation property to an obsolescence reason. The values of obsolescence reasons come from a list of predefined terms, instances of the class obsolescence reason specification.
has obsolescence reason
An administrative note of use for a curator but of no use for a user
curator note
the URI for an OBI Terms ticket at sourceforge, such as https://sourceforge.net/p/obi/obi-terms/772/
An IRI or similar locator for a request or discussion of an ontology term.
The 'tracker item' can associate a tracker with a specific ontology term.
term tracker item
ObjectProperty: RO??? Label: spatially disjoint from Annotations: expand_assertion_to "DisjointClasses: (http://purl.obolibrary.org/obo/BFO_0000051 some ?X) (http://purl.obolibrary.org/obo/BFO_0000051 some ?Y)"
A macro expansion tag applied to an annotation property which can be expanded into a more detailed axiom.
expand assertion to
Ontology annotation property. Relates an ontology to a term that is a designated root term of the ontology. Display tools like OLS can use terms annotated with this property as the starting point for rendering the ontology class hierarchy. There can be more than one root.
has ontology root term
Used when the class or object is scheduled for obsoletion/deprecation on or after a particular date.
scheduled for obsoletion on or after
Use on obsolete terms, relating the term to another term that can be used as a substitute
Add as annotation triples in the granting ontology
term replaced by
CHEBI:26523 (reactive oxygen species) has an exact synonym (ROS), which is of type OMO:0003000 (abbreviation)
A synonym type for describing abbreviations or initalisms
A synonym type for describing dubious synonyms
CHEBI:23367 (molecular entity) has an exact synonym (molecular entities), which is of the type OMO:0003004 (plural form)
A synonym type for describing pluralization synonyms
nasopharynx (UBERON:0001728) has the latin name "pars nasalis pharyngis
A synonym type for describing Latin term synonyms.
tooth SubClassOf 'never in taxon' value 'Aves'
S never_in_taxon T iff: S SubClassOf in_taxon only not T.
x never in taxon T if and only if T is a class, and x does not instantiate the class expression "in taxon some T". Note that this is a shortcut relation, and should be used as a hasValue restriction in OWL.
Class: <http://www.w3.org/2002/07/owl#Nothing> EquivalentTo: ?X and (RO_0002162 some ?Y)
Class: ?X DisjointWith: RO_0002162 some ?Y
A is mutually_spatially_disjoint_with B if both A and B are classes, and there exists no p such that p is part_of some A and p is part_of some B.
Class: <http://www.w3.org/2002/07/owl#Nothing> EquivalentTo: (BFO_0000050 some ?X) and (BFO_0000050 some ?Y)
mutually spatially disjoint with
S ambiguous_for_taxon T if the class S does not have a clear referent in taxon T. An example would be the class 'manual digit 1', which encompasses a homology hypotheses that is accepted for some species (e.g. human and mouse), but does not have a clear referent in Aves - the referent is dependent on the hypothesis embraced, and also on the ontogenetic stage.
S ambiguous_for_taxon T if the class S does not have a clear referent in taxon T. An example would be the class 'manual digit 1', which encompasses a homology hypotheses that is accepted for some species (e.g. human and mouse), but does not have a clear referent in Aves - the referent is dependent on the hypothesis embraced, and also on the ontogenetic stage. [PHENOSCPAE:asilomar_mtg]
ambiguous for taxon
S dubious_for_taxon T if it is probably the case that no instances of S can be found in any instance of T.
This relation lacks a strong logical interpretation, but can be used in place of never_in_taxon where it is desirable to state that the definition of the class is too strict for the taxon under consideration, but placing a never_in_taxon link would result in a chain of inconsistencies that will take ongoing coordinated effort to resolve. Example: metencephalon in teleost
this relation lacks a strong logical interpretation, but can be used in place of never_in_taxon where it is desirable to state that the definition of the class is too strict for the taxon under consideration, but placing a never_in_taxon link would result in a chain of inconsistencies that will take time to resolve. Example: metencephalon in teleost
dubious for taxon
S present_in_taxon T if some instance of T has some S. This does not means that all instances of T have an S - it may only be certain life stages or sexes that have S
The SPARQL expansion for this relation introduces new named classes into the ontology. For this reason it is likely that the expansion should only be performed during a QC pipeline; the expanded output should usually not be included in a published version of the ontology.
present in taxon
'pectoral appendage skeleton' has no connections with 'pelvic appendage skeleton'
A is has_no_connections_with B if there are no parts of A or B that have a connection with the other.
Class: <http://www.w3.org/2002/07/owl#Nothing> EquivalentTo: (BFO_0000050 some ?X) and (RO_0002170 some (BFO_0000050 some ?Y))
An alternate textual definition for a class taken unmodified from an external source. This definition may have been used to derive a generalized definition for the new class.
This annotation property may be replaced with an annotation property from an external ontology such as IAO
A textual description of an axiom loss in this ontology compared to an external ontology.
Notes on the homology status of this class.
An alternate comment for a class taken unmodified from an external source. Note that obo format only allows a single comment for a class, and does not provide a structured means of adding provenance info.
Used to connect a class to an adjectival form of its label. For example, a class with label 'intestine' may have a relational adjective 'intestinal'.
Notes on the how instances of this class vary across species.
Notes on the evolved function of instances of this class.
Notes on the structure, composition or histology of instances of this class.
Notes on the ontogenic development of instances of this class.
Notes on how similar or equivalent classes are represented in other ontologies.
Notes on how lexical conventions regarding this class, in particular any issues that may arise due to homonyny or synonymy.
Notes on how instances of this class functon biomechanically.
Notes on the location, position or part-parents of instances of this class.
A property used in conjunction with repeated_element_number to indicate an axis and directionality along that axis. If P preceding_element_is R, and P is_count_of S, and X P N, and X' P N+1, then it follows that every X R some X', and the class expression [S and R some X' and inv(R) some X] is empty (i.e. X is followed by X', with no intermediates).
A property used to indicate the position of an element where that element is of a type that is serially repeated linearly along some axis for which a total ordering exists. The ordering may represent an ancestral condition.
The range is currently non-negative integer
x pharyngeal_arch_number N if and only if (i) x is a pharyngeal arch, and (ii) x is ancestrally pharyngeal arch number N in a series of pharyngeal arches repeated along a antero-posterior axis, with arch_number 1 being the mandibular arch.
gill arch N = PA N-2. the term branchial_arch is ambiguous.
x ray_number N if and only if (i) x is a ray, and (ii) x is ancestrally associated with ray number N in a series of phalanges repeated along a radio-ulnar or equivalent axis, with ray_number 1 being the anteriormost ray.
The correct terminology is yet to be established; in tetrapods 'ray' might mean the mereological sum of the phalanges of a manual digit plus a metatarsal bone (or equivalent for hindlimb)
x phalanx_number N if and only if (i) x is a phalanx, and (ii) x is phalanx number N in a series of phalanges repeated along an prixomo-distal axis, with phalanx_number 1 being the proximalmost phalanx. Note that in humans, the distalmost phalanx has phlanax_number 3, except in ray_number 1, where the distalmost has phalanx_number 2.
Most land mammals including humans have a 2-3-3-3-3 formula in both the hands (or paws) and feet. Primitive reptiles typically had the formula 2-3-4-4-5, and this pattern, with some modification, remained in many later reptiles and in the mammal-like reptiles. The phalangeal formula in the flippers of cetaceans (marine mammals) is 2-12-8-1
x rib_number N if and only if (i) x is a rib, and (ii) x is rib number N in a series of ribs repeated along an anterior-posterior axis, with rib_number 1 being the anteriormost rib. Note that this property counts ribs, *not* the adjoining vertebrae.
In the early tetrapods, every vertebra bore a pair of ribs, although those on the thoracic vertebrae are typically the longest. In most subsequent forms, many of these early ribs have been lost, and in living amphibians and reptiles, there is great variation in rib structure and number. For example, turtles have only eight pairs of ribs, which are developed into a bony or cartilagenous carapace and plastron, while snakes have numerous ribs running along the full length of their trunk. Frogs typically have no ribs, aside from a sacral pair, which form part of the pelvis. Mammals usually also only have distinct ribs on the thoracic vertebra, although fixed cervical ribs are also present in monotremes. In marsupials and placental mammals, the cervical and lumbar ribs are found only as tiny remnants fused to the vertebrae, where they are referred to as transverse processes. In general, the structure and number of the true ribs in humans is similar to that in other mammals. Unlike reptiles, caudal ribs are never found in mammals.
Note that in TAO, ribs are numbered by *vertebrae*
x vertebra_number N if and only if (i) x is a vertebra, and (ii) x is vertebra number N in a series of vertebras repeated along an anterior-posterior axis, with vertebra_number 1 being the anteriormost vertebra (also known as the atlas).
x somite_number N if and only if (i) x is a somite, and (ii) x is somite number N in a series of somites repeated along an anterior-posterior axis, with somite_number 1 being the anteriormost somite.
x paired_appendage_number N if and only if (i) x is a paired_appendage, and (ii) x is paired_appendage number N in a series of paired_appendages repeated along an anterior-posterior axis, with paired_appendage_number 1 being the anteriormost paired_appendage. In vertebrates, this is the pectoral appendage.
x appendage_segment_number N if and only if (i) x is a appendage_segment, and (ii) x is appendage_segment number N in a series of appendage_segments repeated along an proximo-distal axis, with appendage_segment_number 1 being the proximalmost appendage_segment (in tetrapods this would be the stylopod, as we do not classify girdles as appendage segments).
Examples: in dropsphila coxa=1, trochanter=2, femur=3, tibia=4, tarsal segments 1-5=5-9, pretarsus=10
x rhombomere_number N if and only if (i) x is a rhombomere, and (ii) x is rhombomere number N in a series of rhombomeres repeated along an anterior-posterior axis, with rhombomere_number 1 being the anteriormost rhombomere.
x tooth_number N if and only if (i) x is a tooth, and (ii) x is ancestrally tooth number N in a series of teeth repeated along an anterior-posterior axis, typically on the lateral side of a structure such as a jaw, with tooth_number 1 being the anteriormost. Note that this count refers to the total number of teeth starting from the first, regardless of the type of tooth. If sub-systems are required for numbering within a series of teeth of the same type, consider a subproperty. For example, in a human, maxillary canine = tooth 3 of upper jaw = canine_tooth 1 of upper jaw.
Syntax: upper/lower = I.C.P.M / I.C.P.M. When used with generic tooth class applies to both deciduous and primary. Should also be used with a taxon property.
FMA has terms like 'set of X'. In general we do not include set-of terms in uberon, but provide a mapping between the singular form and the FMA set term
preferred term in the context of comparative anatomy
A historic synonym, no longer encouraged
a synonym made on the basis of a possibly homologous structure in another species
preferred term when talking about an instance of this class in Homo sapiens
indicates that a synonym is used in an inconsistent or confusing way, typically between species
a mis-spelling that is in common use and thus recorded
synonym that is inappropriate for amniotes
synonym that is inappropriate for mammals
expert consultation and attribution required
a systematic synonym used as the base name for design patterns
Classes tagged with this subset property were added upon request from the Human Cell Atlas (HCA).
Terms applicable across life, not restricted to Metazoa
brain region defined by cyto-architecture
classes that are defined by relative position counting from first in a series of elements along an axis in an individual organism rather than by strict homology
Indicates that subclasses in AOs may be inappropriately linked
A class that represents an early developmental structure, like a blastocyst. This part of the ontology is undergoing review to remove inappropriate grouping classes.
derived from the union of EHDAA2 and EMAPA - still to be checked
subset of classes that have logical defs text defs and synonyms aligned with FEED
Subset consisting of classes creating for grouping purposes
A grouping class that depends on an assumption of homology between subclasses
classes that have some inconsistency with FMA
somewhat fuzzy grouping for analysis purposes, currently composed of something like: liver, heart, skeletal, kidney, bladder, brain, skin, mouth, esophagus, stomach, small intestine, large intestines, trachea nose, lungs, brain, spinal cord, peripheral nerves, kidneys, ureters, bladder, urethra, gonads
core classes typically found across metazoa. one purpose is to create a rough set of terms that could be used to start a new metazoan AO. Note this subset is not yet fully fleshed out
abstract class brought in to group ontology classes but not informative
organs, excluding individual muscles and skeletal elements
A subset specifically created for the 2012 Phenotype RCN meeting. Includes some human-specific terms that may eventually be removed when they are adequately represented with part of relationships in FMA
Uberon slim - subset that excludes obscure terms and deep compositional terms
Indicates that the class encompasses classes from other AOs that have not been verified
abstract upper-level terms not directly useful for analysis
core classes typically found across vertebrates. one purpose is to create a rough set of terms that could be used to start a new vertebrate AO
An alternative label for a class or property which has a more general meaning than the preferred name/primary label.
has broad synonym
An alternative label for a class or property which has the exact same meaning than the preferred name/primary label.
has exact synonym
An alternative label for a class or property which has a more specific meaning than the preferred name/primary label.
has narrow synonym
An alternative label for a class or property that has been used synonymously with the primary term name, but the usage is not strictly correct.
has related synonym
my brain is part of my body (continuant parthood, two material entities)
my stomach cavity is part of my stomach (continuant parthood, immaterial entity is part of material entity)
this day is part of this year (occurrent parthood)
a core relation that holds between a part and its whole
Everything is part of itself. Any part of any part of a thing is itself part of that thing. Two distinct things cannot be part of each other.
Occurrents are not subject to change and so parthood between occurrents holds for all the times that the part exists. Many continuants are subject to change, so parthood between continuants will only hold at certain times, but this is difficult to specify in OWL. See http://purl.obolibrary.org/obo/ro/docs/temporal-semantics/
Parthood requires the part and the whole to have compatible classes: only an occurrent can be part of an occurrent; only a process can be part of a process; only a continuant can be part of a continuant; only an independent continuant can be part of an independent continuant; only an immaterial entity can be part of an immaterial entity; only a specifically dependent continuant can be part of a specifically dependent continuant; only a generically dependent continuant can be part of a generically dependent continuant. (This list is not exhaustive.) A continuant cannot be part of an occurrent: use 'participates in'. An occurrent cannot be part of a continuant: use 'has participant'. A material entity cannot be part of an immaterial entity: use 'has location'. A specifically dependent continuant cannot be part of an independent continuant: use 'inheres in'. An independent continuant cannot be part of a specifically dependent continuant: use 'bearer of'.
part of
x develops from y if and only if either (a) x directly develops from y or (b) there exists some z such that x directly develops from z and z develops from y
This is the transitive form of the develops from relation
develops from
x transformation of y if x is the immediate transformation of y, or is linked to y through a chain of transformation relationships
x immediate transformation of y iff x immediately succeeds y temporally at a time boundary t, and all of the matter present in x at t is present in y at t, and all the matter in y at t is present in x at t
A major division of the nervous system that contains nerves which connect the central nervous system (CNS) with sensory organs, other organs, muscles, blood vessels and glands.
Nervous structures including ganglia outside of the central nervous system. Kimmel et al, 1995.[TAO]
Part of nervous system in which nerves extend throughout the body outside of the brain and spinal cord.[AAO]
The peripheral nervous system (PNS) is the part of the nervous system connected to the CNS which contains cranial nerves III - XII, spinal, peripheral and autonomic nerves. (CUMBO)
(...) specific vertebrate traits within the chordate phylum such as skeletal tissues, PNS, and spectacular head and brain development, are linked to the NC (neural crest) and its derivatives.[well established][VHOG]
DOI:10.1007/978-0-387-46954-6_6 Dupin E, Creuzet S, Le Douarin NM, The contribution of the neural crest to the vertebrate body. Advances in experimental medicine and biology (2006)
A spatially aggregated collection of nerve cell bodies in the CNS, consisting of one or more subpopulations that share cell type, chemical phenotype, and connections, and including nearby cells that share the same cell type, chemical phenotype, and connections. (CUMBO).
Anatomical structure consisting of a discrete aggregate of neuronal soma[GO][GO_REF:0000021].
Proposed CUMBO def from MM: A subcortical part of the nervous system consisting of a relatively compact group of cells that is distinguishable histologically that share a commonality of cytoarchitecture, chemoarchitecturel and connectivity. (comments: I put in 'subcortical' because I don't think we consider either the cerebellar cortex or cerebral cortex to be nuclei. Some people distinguish between a nucleus and a laminar structure (see Wikipedia definition). However, there are structures identified as nuclei that are laminar, e.g., lateral geniculate nucleus, although they are not laminated in all species. Also, I put in 'relatively compact' and 'distiguishable by histology' because we have groups of cells, e.g., cholinergic cell groups, doparminergic cell groups that are related on the 3 criteria but which we don't tend to consider nuclei because they don't occupy an easily defined territory. But all is open to debate.
The brain is the center of the nervous system in all vertebrate, and most invertebrate, animals. Some primitive animals such as jellyfish and starfish have a decentralized nervous system without a brain, while sponges lack any nervous system at all. In vertebrates, the brain is located in the head, protected by the skull and close to the primary sensory apparatus of vision, hearing, balance, taste, and smell[WP].
requires review for applicability to invertebrate structures, e.g. synganglion
Cavitated compound organ which is comprised of gray and white matter and surrounds the cerebral ventricular system.[TAO]
Part of the central nervous system situated within the cranium and composed of both nerve cell bodies and nerve fibers.[AAO]
The part of the central nervous system contained within the cranium, comprising the forebrain, midbrain, hindbrain, and metencephalon. It is derived from the anterior part of the embryonic neural tube (or the encephalon). Does not include retina. (CUMBO)
(...) at some stage of its development, every chordate exhibits five uniquely derived characters or synapomorphies of the group: (...) (4) a single, tubular nerve cord that is located dorsal to the notochord (...) (reference 1); The neural tube is destined to differentiate into the brain and spinal cord (the central nervous system) (reference 2).[well established][VHOG]
ISBN:978-0030223693 Liem KF, Bemis WE, Walker WF, Grande L, Functional Anatomy of the Vertebrates: An Evolutionary Perspective (2001) p.28, ISBN:978-0072528305 Kardong KV, Vertebrates: Comparative Anatomy, Function, Evolution (2006) p.165
The nervous system is an organ system containing predominantly neuron and glial cells. In bilaterally symmetrical organism, it is arranged in a network of tree-like structures connected to a central body. The main functions of the nervous system are to regulate and control body functions, and to receive sensory input, process this information, and generate behavior [CUMBO].
A regulatory system of the body that consists of neurons and neuroglial cells. The nervous system is divided into two parts, the central nervous system (CNS) and the peripheral nervous system (PNS). (Source: BioGlossary, www.Biology-Text.com)[TAO]
Anatomical system consisting of nerve bodies and nerve fibers which regulate the response of the body to external and internal stimuli.[AAO]
Nervous systems evolved in the ancestor of Eumetazoa.[well established][VHOG]
ISBN:978-0198566694 Schmidt-Rhaesa A, The evolution of organ systems (2007) p.117
The central nervous system is the core nervous system that serves an integrating and coordinating function. In vertebrates it consists of the neural tube derivatives: the brain and spinal cord. In invertebrates it includes central ganglia plus nerve cord.
Part of the nervous system which includes the brain and spinal cord.[AAO]
The brain and spinal cord. Kimmel et al, 1995.[TAO]
The central nervous system (CNS) is the part of the nervous system which includes the brain, spinal cord, and nerve cell layer of the retina (CUMBO).
(...) at some stage of its development, every chordate exhibits five uniquely derived characters or synapomorphies of the group: (...) (4) a single, tubular nerve cord that is located dorsal to the notochord (...) (reference 1); The neural tube is destined to differentiate into the brain and spinal cord (the central nervous system) (reference 2); Taken together, our data make a very strong case that the complex molecular mediolateral architecture of the developing trunk CNS (central nervous system), as shared between Platynereis and vertebrates, was already present in their last common ancestor, Urbilateria. The concept of bilaterian nervous system centralization implies that neuron types concentrate on one side of the trunk, as is the case in vertebrates and many invertebrates including Platynereis, where they segregate and become spatially organized (as opposed to a diffuse nerve net). Our data reveal that a large part of the spatial organization of the annelid and vertebrate CNS was already present in their last common ancestor, which implies that Urbilateria had already possessed a CNS (reference 3).[well established][VHOG]
ISBN:978-0030223693 Liem KF, Bemis WE, Walker WF, Grande L, Functional Anatomy of the Vertebrates: An Evolutionary Perspective (2001) p.28 (reference 1), ISBN:978-0072528305 Kardong KV, Vertebrates: Comparative Anatomy, Function, Evolution (2006) p.165 (reference 2), DOI:10.1016/j.cell.2007.02.040 Denes AS, Jekely G, Steinmetz PRH, Raible F, Snyman H, Prud'homme B, Ferrier DEK, Balavoine G and Arendt D, Molecular architecture of annelid nerve cord supports common origin of nervous system centralization in Bilateria. Cell (2007) (reference 3)
A group of axons linking two or more neuropils and having a common origin, termination[FBbt].
White matter structure of CNS that contains axons that arise predominantly in one central nervous system part and terminate in another. Tracts are generally named by their region or origin followed by their region of primary termination, e.g., mammillothalamic tract contains axons that arise from neurons in the mammillary bodies and terminate in the thalamus. (CUMBO)
WP says this is the analog of peripheral nerves in CNS.
Axon tract that crosses the midline of the central nervous system[NIF, modified]. In the context of Drosophila refers to a broad band of axons connecting equivalent neuropils each side of the brain[FBbt].
White matter fiber bundle that crosses the midline of the brain or spinal cord, that connects similar structures on both sides. (CUMBO; Heimer, L. The Human Brain, 2nd ed., 1995, pg 6)
Part of the central nervous system located in the vertebral canal continuous with and caudal to the brain; demarcated from brain by plane of foramen magnum. It is composed of an inner core of gray matter in which nerve cells predominate, and an outer layer of white matter in which myelinated nerve fibers predominate, and surrounds the central canal. (CUMBO).
TODO - add superclass to unify with VNC?
Part of the central nervous system which descends from the hindbrain within the vertebral column.[AAO]
A spatially aggregated collection of nerve cell bodies in the PNS, consisting of one or more subpopulations that share cell type, chemical phenotype, and connections. (CUMBO).
we follow MA in including separate classes for ganglion and peripheral nervous system, even though for vertebrates gangia are always in the PNS
The embryonic precursor of the brain and the set of mature brain structures that derive from it (CUMBO)
Nerve fibers crossing the midline of the neuraxis relative to their point of origin, on a course to from one level of the nervous system to another. (CUMBO, Heimer, L. The Human Brain, 2nd ed., 1995, pg 6).
A depression or fissure in the surface of the brain. It surrounds the gyri, creating the characteristic appearance of the brain in humans and other large mammals.
sulci are considered absent from lissencephalic mammals such as mice, but they may possess fissures. For example, the Allen mouse brain Atlas includes hippocampal, rhinal and choroid fissure. For this reason we do not place a taxon constraint on this class
Indentation on the surface of the brain or spinal cord that forms a recognizable landmark, e.g., central sulcus, sulcus limitans (CUMBO)
A group of cells that may not be contained within macroscopic anatomical boundaries, e.g., A9 dopaminergic cell group; massa intercalata of the amygdala (CUMBO).
Single layer of a laminar structure, identified by different density, arrangement or size of cells and processes arranged in flattened layers or lamina[CUMBO].
this is currently used to group some cellular layers that may not strictly conform to the CARO definition of cell-part layer. Consider genericisizing and introducing subtypes for cellular layer, fibrous layer and cell soma layer