Piriform cortex
Encyclopedia
In anatomy
of animal
s, the piriform cortex, or pyriform cortex is a region in the brain
.
situated in the telencephalon
.
In human anatomy, the "piriform lobe" has been described as consisting of the cortical amygdala
, uncus
, and anterior parahippocampal gyrus
.
The function of the piriform cortex relates to olfaction
, which is the perception of smell
s.
s and mammal
s.
The piriform cortex is among three areas that emerge in the telencephalon
of amphibians, situated caudally to a dorsal area, which is caudal to a hippocampal area. Farther along the phylogenic timeline, the telencephalic bulb of reptiles as viewed in a cross section of the transverse plane extends with the archipallial
hippocampus folding toward the midline and down as the dorsal area begins to form a recognizable cortex.
As mammalian cerebrums developed, volume of the dorsal cortex increased in slightly greater proportion, as compared proportionally with increased overall brain volume, until it enveloped the hippocampal
regions. Recognized as neopallium or neocortex
, enlarged dorsal areas envelop the paleopallial
piriform cortex in human
s and Old World monkey
s.
Among taxonomic groupings of mammals, the piriform cortex and the olfactory bulb
become proportionally smaller in the brains of phylogenically younger species. The piriform cortex occupies a greater proportion of the overall brain and of the telencephalic brains of insectivore
s than in primate
s. The piriform cortex continues to occupy a consistent albeit small and declining proportion of the increasingly large telencephalon
in the most recent primate species while the volume of the olfactory bulb becomes less in proportion.
It is Brodmann area 27
.
Anatomy
Anatomy is a branch of biology and medicine that is the consideration of the structure of living things. It is a general term that includes human anatomy, animal anatomy , and plant anatomy...
of animal
Animal
Animals are a major group of multicellular, eukaryotic organisms of the kingdom Animalia or Metazoa. Their body plan eventually becomes fixed as they develop, although some undergo a process of metamorphosis later on in their life. Most animals are motile, meaning they can move spontaneously and...
s, the piriform cortex, or pyriform cortex is a region in 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,...
.
Anatomy and function
The piriform cortex is part of the rhinencephalonRhinencephalon
In animal anatomy, the rhinencephalon is a part of the brain involved with olfaction.-Components:The term rhinencephalon has been used to describe different structures at different points in time....
situated in the telencephalon
Telencephalon
The cerebrum or telencephalon, together with the diencephalon, constitutes the forebrain. The cerebrum is the most anterior region of the vertebrate central nervous system. Telencephalon refers to the embryonic structure, from which the mature cerebrum develops...
.
In human anatomy, the "piriform lobe" has been described as consisting of the cortical amygdala
Amygdala
The ' are almond-shaped groups of nuclei located deep within the medial temporal lobes of the brain in complex vertebrates, including humans. Shown in research to perform a primary role in the processing and memory of emotional reactions, the amygdalae are considered part of the limbic system.-...
, uncus
Uncus
The anterior extremity of the Parahippocampal gyrus is recurved in the form of a hook, the uncus, which is separated from the apex of the temporal lobe by a slight fissure, the incisura temporalis....
, and anterior parahippocampal gyrus
Parahippocampal gyrus
The parahippocampal gyrus is a grey matter cortical region of the brain that surrounds the hippocampus. This region plays an important role in memory encoding and retrieval....
.
The function of the piriform cortex relates to olfaction
Olfaction
Olfaction is the sense of smell. This sense is mediated by specialized sensory cells of the nasal cavity of vertebrates, and, by analogy, sensory cells of the antennae of invertebrates...
, which is the perception of smell
Odor
An odor or odour is caused by one or more volatilized chemical compounds, generally at a very low concentration, that humans or other animals perceive by the sense of olfaction. Odors are also commonly called scents, which can refer to both pleasant and unpleasant odors...
s.
Phylogeny
Sometimes called the olfactory cortex, olfactory lobe or paleopallium, piriform cortical regions are present in the brains of amphibians, reptileReptile
Reptiles are members of a class of air-breathing, ectothermic vertebrates which are characterized by laying shelled eggs , and having skin covered in scales and/or scutes. They are tetrapods, either having four limbs or being descended from four-limbed ancestors...
s and mammal
Mammal
Mammals are members of a class of air-breathing vertebrate animals characterised by the possession of endothermy, hair, three middle ear bones, and mammary glands functional in mothers with young...
s.
The piriform cortex is among three areas that emerge in the telencephalon
Telencephalon
The cerebrum or telencephalon, together with the diencephalon, constitutes the forebrain. The cerebrum is the most anterior region of the vertebrate central nervous system. Telencephalon refers to the embryonic structure, from which the mature cerebrum develops...
of amphibians, situated caudally to a dorsal area, which is caudal to a hippocampal area. Farther along the phylogenic timeline, the telencephalic bulb of reptiles as viewed in a cross section of the transverse plane extends with the archipallial
Archipallium
In anatomy of animals, the archipallium is the oldest region of the brain's pallium.The archipallium is often considered contiguous with the olfactory cortex, but the extent of the archipallium varies among species. In older species, such as fish, the archipallium makes up most of the cerebrum...
hippocampus folding toward the midline and down as the dorsal area begins to form a recognizable cortex.
As mammalian cerebrums developed, volume of the dorsal cortex increased in slightly greater proportion, as compared proportionally with increased overall brain volume, until it enveloped the hippocampal
Hippocampus
The hippocampus is a major component of the brains of humans and other vertebrates. It belongs to the limbic system and plays important roles in the consolidation of information from short-term memory to long-term memory and spatial navigation. Humans and other mammals have two hippocampi, one in...
regions. Recognized as neopallium or neocortex
Neocortex
The neocortex , also called the neopallium and isocortex , is a part of the brain of mammals. It is the outer layer of the cerebral hemispheres, and made up of six layers, labelled I to VI...
, enlarged dorsal areas envelop the paleopallial
Paleopallium
In anatomy of animals, the paleopallium is a region within the telencephalon in the brain.It is a primitive and evolutionarily ancient region of the brain, first appearing in amphibians....
piriform cortex in human
Human
Humans are the only living species in the Homo genus...
s and Old World monkey
Old World monkey
The Old World monkeys or Cercopithecidae are a group of primates, falling in the superfamily Cercopithecoidea in the clade Catarrhini. The Old World monkeys are native to Africa and Asia today, inhabiting a range of environments from tropical rain forest to savanna, shrubland and mountainous...
s.
Among taxonomic groupings of mammals, the piriform cortex and the olfactory bulb
Olfactory bulb
The olfactory bulb is a structure of the vertebrate forebrain involved in olfaction, the perception of odors.-Anatomy:In most vertebrates, the olfactory bulb is the most rostral part of the brain. In humans, however, the olfactory bulb is on the inferior side of the brain...
become proportionally smaller in the brains of phylogenically younger species. The piriform cortex occupies a greater proportion of the overall brain and of the telencephalic brains of insectivore
Insectivore
An insectivore is a type of carnivore with a diet that consists chiefly of insects and similar small creatures. An alternate term is entomophage, which also refers to the human practice of eating insects....
s than in primate
Primate
A primate is a mammal of the order Primates , which contains prosimians and simians. Primates arose from ancestors that lived in the trees of tropical forests; many primate characteristics represent adaptations to life in this challenging three-dimensional environment...
s. The piriform cortex continues to occupy a consistent albeit small and declining proportion of the increasingly large telencephalon
Telencephalon
The cerebrum or telencephalon, together with the diencephalon, constitutes the forebrain. The cerebrum is the most anterior region of the vertebrate central nervous system. Telencephalon refers to the embryonic structure, from which the mature cerebrum develops...
in the most recent primate species while the volume of the olfactory bulb becomes less in proportion.
It is Brodmann area 27
Brodmann area 27
Area 27 of Brodmann-1909 is a cytoarchitecturally defined cortical area that is a rostral part of the parahippocampal gyrus of the guenon . It is commonly regarded as a synonym of presubiculum .-External links:...
.