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Paleocortex
In anatomy of animals, the paleocortex, or paleopallium, is a region within the telencephalon in the vertebrate brain. This type of cortical tissue consists of three cortical laminae (layers of neuronal cell bodies). In comparison, the neocortex has six layers and the archicortex has three or four layers. Because the number of laminae that compose a type of cortical tissue seems to be directly proportional to both the information-processing capabilities of that tissue and its phylogenetic age, paleocortex is thought to be an intermediate between the archicortex (or archipallium) and the neocortex (or neopallium) in both aspects. The paleocortex (or paleopallium) and the archicortex (or the archipallium) of the cerebral cortex together constitute the mammalian allocortex or the heterogenetic cortex. The distinction for what is called neocortex or isocortex, which comprises most of the human brain (about 90%), is made from the number of cellular layers that the structure compri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Allocortex
The allocortex or heterogenetic cortex, and neocortex are the two types of cerebral cortex in the brain. The allocortex is the much smaller area of cortex taking up just 10 %, the neocortex takes up the remaining 90 %. It is characterized by having just three or four cortical layers, in contrast with the six layers of the neocortex. There are three subtypes of allocortex: the paleocortex, the archicortex, and the periallocortex—a transitional zone between the neocortex and the allocortex. The specific regions of the brain usually described as belonging to the allocortex are the olfactory system, and the hippocampus. Allocortex is termed heterogenetic cortex, because during development it never has the six-layered architecture of homogenetic neocortex. It differs from hetero''typic'' cortex, a type of cerebral cortex, which during prenatal development, passes through a six-layered stage to have fewer layers, such as in Brodmann area 4 that lacks granule cells. Structure Th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Archicortex
The archicortex, or archipallium, is the phylogenetically oldest region of the brain's cerebral cortex. It is often considered contiguous with the olfactory cortex, but its extent varies among species. In older species, such as fish, the archipallium makes up most of the cerebrum. Amphibians develop an archipallium and paleopallium. In humans, the archicortex makes up the three cortical layers of the hippocampus. It has fewer cortical layers than both the neocortex, which has six, and the paleocortex, which has either four or five. The archicortex, along with the paleocortex and periallocortex, is a subtype of allocortex. Because the number of cortical layers that make up a type of cortical tissue seems to be directly proportional to both the information-processing capabilities of that tissue and its phylogenetic age, the archicortex is thought to be the oldest and most basic type of cortical tissue. Location The archicortex is most prevalent in the olfactory cortex and t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cerebral Cortex
The cerebral cortex, also known as the cerebral mantle, is the outer layer of neural tissue of the cerebrum of the brain in humans and other mammals. The cerebral cortex mostly consists of the six-layered neocortex, with just 10% consisting of allocortex. It is separated into two cortices, by the longitudinal fissure that divides the cerebrum into the left and right cerebral hemispheres. The two hemispheres are joined beneath the cortex by the corpus callosum. The cerebral cortex is the largest site of neural integration in the central nervous system. It plays a key role in attention, perception, awareness, thought, memory, language, and consciousness. The cerebral cortex is part of the brain responsible for cognition. In most mammals, apart from small mammals that have small brains, the cerebral cortex is folded, providing a greater surface area in the confined volume of the cranium. Apart from minimising brain and cranial volume, cortical folding is crucial f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anterior Olfactory Nucleus
The anterior olfactory nucleus (AON; also called the anterior olfactory cortex) is a portion of the forebrain of vertebrates. It is involved in olfaction and has supposedly strong influence on other olfactory areas like the olfactory bulb and the piriform cortex. Structure The AON is found behind the olfactory bulb and in front of the piriform cortex (laterally) and olfactory tubercle (medially) in a region known as the olfactory peduncle or retrobulbar area. The peduncle contains the AON as well as two other much smaller regions, the taenia tecta (or dorsal hippocampal rudiment) and the dorsal peduncular cortex. Function The AON plays a pivotal but relatively poorly understood role in the processing of odor information. Odors enter the nose (or olfactory rosette in fishes) and interact with the cilia of olfactory receptor neurons. The information is sent via the olfactory nerve (Cranial Nerve I) to the olfactory bulb. After the processing in the bulb the signal is transmitte ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cerebrum
The cerebrum, telencephalon or endbrain is the largest part of the brain containing the cerebral cortex (of the two cerebral hemispheres), as well as several subcortical structures, including the hippocampus, basal ganglia, and olfactory bulb. In the human brain, the cerebrum is the uppermost region of the central nervous system. The cerebrum develops prenatally from the forebrain (prosencephalon). In mammals, the dorsal telencephalon, or pallium, develops into the cerebral cortex, and the ventral telencephalon, or subpallium, becomes the basal ganglia. The cerebrum is also divided into approximately symmetric left and right cerebral hemispheres. With the assistance of the cerebellum, the cerebrum controls all voluntary actions in the human body. Structure The cerebrum is the largest part of the brain. Depending upon the position of the animal it lies either in front or on top of the brainstem. In humans, the cerebrum is the largest and best-developed of the five ma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
List Of Regions In The Human Brain
The human brain anatomical regions are ordered following standard neuroanatomy hierarchies. Functional, connective, and developmental regions are listed in parentheses where appropriate. Hindbrain (rhombencephalon) Myelencephalon *Medulla oblongata **Medullary pyramids **Arcuate nucleus ** Olivary body *** Inferior olivary nucleus **Rostral ventrolateral medulla **Caudal ventrolateral medulla **Solitary nucleus (Nucleus of the solitary tract) **Respiratory center- Respiratory groups *** Dorsal respiratory group *** Ventral respiratory group or Apneustic centre ****Pre-Bötzinger complex **** Botzinger complex **** Retrotrapezoid nucleus **** Nucleus retrofacialis **** Nucleus retroambiguus **** Nucleus para-ambiguus ** Paramedian reticular nucleus ** Gigantocellular reticular nucleus **Parafacial zone ** Cuneate nucleus **Gracile nucleus ** Perihypoglossal nuclei *** Intercalated nucleus *** Prepositus nucleus *** Sublingual nucleus ** Area postrema **Medullary cr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paralimbic Cortex
The paralimbic cortex is an area of three-layered Cerebral cortex, cortex that includes the following regions: the piriform cortex, entorhinal cortex, the parahippocampal cortex on the Anatomical terms of location#Left and right (lateral), and medial, medial surface of the temporal lobe, and the cingulate cortex just above the corpus callosum.Kolb & Whishaw: ''Fundamentals of Human Neuropsychology'', 2003. The paralimbic cortex lies close to, and is directly connected with, the structures of the limbic system. (The prefix ''para'' meaning beside or adjacent to.) The paralimbic cortex, also referred to as the mesocortex, or juxtallocortex, is interposed between the neocortex and the allocortex. The paralimbic cortex provides a gradual transition from primary limbic regions, including the septal nuclei, septal region, substantia innominata, and the amygdala nuclei, to higher neocortical regions. There are dense connections between the paralimbic cortex and core limbic structures, i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Uncus
The uncus is an anterior extremity of the parahippocampal gyrus. It is separated from the apex of the temporal lobe by a slight fissure called the incisura temporalis (also called rhinal sulcus). Although superficially continuous with the hippocampal gyrus, the uncus forms morphologically a part of the rhinencephalon. An important landmark that crosses the inferior surface of the uncus is the band of Giacomini. The term comes from the Latin word uncus, meaning ''hook'', and it was coined by Félix Vicq-d'Azyr (1748–1794).JC Tamraz, YG Comair. Atlas of Regional Anatomy of the Brain Using MRI (2006), p 8. Clinical significance The part of the olfactory cortex that is on the temporal lobe covers the area of the uncus, which leads into the two significant clinical aspects of the uncus: uncinate fits and uncal herniations. * Seizures, often preceded by hallucinations of disagreeable odors, often originate in the uncus. * In situations of tumor, hemorrhage, or edema, increa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anterior Commissure
The anterior commissure (also known as the precommissure) is a white matter tract (a bundle of axons) connecting the two temporal lobes of the cerebral hemispheres across the midline, and placed in front of the columns of the fornix. In most existing mammals, the great majority of fibers connecting the two hemispheres travel through the corpus callosum, which is over 10 times larger than the anterior commissure, and other routes of communication pass through the hippocampal commissure or, indirectly, via subcortical connections. Nevertheless, the anterior commissure is a significant pathway that can be clearly distinguished in the brains of all mammals. The anterior commissure plays a key role in pain sensation, more specifically sharp, acute pain. It also contains decussating fibers from the olfactory tracts, vital for the sense of smell and chemoreception. The anterior commissure works with the posterior commissure to link the two cerebral hemispheres of the brain and als ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Olfactory Tract
The olfactory tract is a bilateral bundle of afferent nerve fibers from the mitral and tufted cells of the olfactory bulb that connects to several target regions in the brain, including the piriform cortex, amygdala, and entorhinal cortex. It is a narrow white band, triangular on coronal section, the apex being directed upward. Structure The olfactory tract and olfactory bulb lie in the olfactory sulcus a sulcus formed by the medial orbital gyrus on the inferior surface of each frontal lobe. The olfactory tracts lie in the sulci which run closely parallel to the midline. Fibers of the olfactory tract appear to end in the antero-lateral part of the olfactory tubercle, the dorsal and external parts of the anterior olfactory nucleus, the frontal and temporal parts of the prepyriform area, the cortico-medial group of amygdala nuclei and the nucleus of the stria terminalis. The olfactory tract divides posteriorly into a medial and a lateral stria. Caudal to this is the olfacto ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anterior Olfactory Nucleus
The anterior olfactory nucleus (AON; also called the anterior olfactory cortex) is a portion of the forebrain of vertebrates. It is involved in olfaction and has supposedly strong influence on other olfactory areas like the olfactory bulb and the piriform cortex. Structure The AON is found behind the olfactory bulb and in front of the piriform cortex (laterally) and olfactory tubercle (medially) in a region known as the olfactory peduncle or retrobulbar area. The peduncle contains the AON as well as two other much smaller regions, the taenia tecta (or dorsal hippocampal rudiment) and the dorsal peduncular cortex. Function The AON plays a pivotal but relatively poorly understood role in the processing of odor information. Odors enter the nose (or olfactory rosette in fishes) and interact with the cilia of olfactory receptor neurons. The information is sent via the olfactory nerve (Cranial Nerve I) to the olfactory bulb. After the processing in the bulb the signal is transmitte ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Piriform Cortex
The piriform cortex, or pyriform cortex, is a region in the brain, part of the rhinencephalon situated in the cerebrum. The function of the piriform cortex relates to the sense of smell. Structure The piriform cortex is part of the rhinencephalon situated in the cerebrum. In human anatomy, the piriform cortex has been described as consisting of the cortical amygdala, uncus, and anterior parahippocampal gyrus. More specifically, the human piriform cortex is located between the insula and the temporal lobe, anteriorly and laterally of the amygdala.Howard, J. D., Plailly, J., Grueschow, M., Haynes, J. D., & Gottfried, J. A. (2009). Odor quality coding and categorization in human posterior piriform cortex. Nature neuroscience, 12(7), 932-938. Supplementary material, p.4 Function The function of the piriform cortex relates to olfaction, which is the perception of smell. This has been particularly shown in humans for the posterior piriform cortex. The piriform cortex in rodents a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
