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Gyrus
In neuroanatomy, a gyrus (pl. gyri) is a ridge on the cerebral cortex. It is generally surrounded by one or more sulci (depressions or furrows; sg. ''sulcus''). Gyri and sulci create the folded appearance of the brain in humans and other mammals. Structure The gyri are part of a system of folds and ridges that create a larger surface area for the human brain and other mammalian brains. Because the brain is confined to the skull, brain size is limited. Ridges and depressions create folds allowing a larger cortical surface area, and greater cognitive function, to exist in the confines of a smaller cranium. Development The human brain undergoes gyrification during fetal and neonatal development. In embryonic development, all mammalian brains begin as smooth structures derived from the neural tube. A cerebral cortex without surface convolutions is lissencephalic, meaning 'smooth-brained'. As development continues, gyri and sulci begin to take shape on the fetal brain, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Inferior Frontal Gyrus
The inferior frontal gyrus (IFG), (gyrus frontalis inferior), is the lowest positioned gyrus of the frontal gyri, of the frontal lobe, and is part of the prefrontal cortex. Its superior border is the inferior frontal sulcus (which divides it from the middle frontal gyrus), its inferior border is the lateral sulcus (which divides it from the superior temporal gyrus) and its posterior border is the inferior precentral sulcus. Above it is the middle frontal gyrus, behind it is the precentral gyrus. The inferior frontal gyrus contains Broca's area, which is involved in language processing and speech production. Structure The inferior frontal gyrus is highly convoluted and has three cytoarchitecturally diverse regions. The three subdivisions are an opercular part, a triangular part, and an orbital part. These divisions are marked by two rami arising from the lateral sulcus. The ascending ramus separates the opercular and triangular parts. The anterior (horizontal) ramus sep ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Superior Temporal Gyrus
The superior temporal gyrus (STG) is one of three (sometimes two) gyri in the temporal lobe of the human brain, which is located laterally to the head, situated somewhat above the external ear. The superior temporal gyrus is bounded by: * the lateral sulcus above; * the superior temporal sulcus (not always present or visible) below; * an imaginary line drawn from the preoccipital notch to the lateral sulcus posteriorly. The superior temporal gyrus contains several important structures of the brain, including: * Brodmann areas 41 and 42, marking the location of the auditory cortex, the cortical region responsible for the sensation of sound; * Wernicke's area, Brodmann 22p, an important region for the processing of speech so that it can be understood as language. The superior temporal gyrus contains the auditory cortex, which is responsible for processing sounds. Specific sound frequencies map precisely onto the auditory cortex. This auditory (or tonotopic) map is similar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gyri
In neuroanatomy, a gyrus (pl. gyri) is a ridge on the cerebral cortex. It is generally surrounded by one or more sulci (depressions or furrows; sg. ''sulcus''). Gyri and sulci create the folded appearance of the brain in humans and other mammals. Structure The gyri are part of a system of folds and ridges that create a larger surface area for the human brain and other mammalian brains. Because the brain is confined to the skull, brain size is limited. Ridges and depressions create folds allowing a larger cortical surface area, and greater cognitive function, to exist in the confines of a smaller cranium. Development The human brain undergoes gyrification during fetal and neonatal development. In embryonic development, all mammalian brains begin as smooth structures derived from the neural tube. A cerebral cortex without surface convolutions is lissencephalic, meaning 'smooth-brained'. As development continues, gyri and sulci begin to take shape on the fetal brain, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Middle Frontal Gyrus
The middle frontal gyrus makes up about one-third of the frontal lobe of the human brain. (A ''gyrus'' is one of the prominent "bumps" or "ridges" on the surface of the human brain.) The middle frontal gyrus, like the inferior frontal gyrus and the superior frontal gyrus, is more of a region in the frontal gyrus than a true gyrus. The borders of the middle frontal gyrus are the ''inferior frontal sulcus'' below; the ''superior frontal sulcus'' above; and the precentral sulcus The precentral sulcus is a part of the human brain that lies parallel to, and in front of, the central sulcus. (A ''sulcus'' is one of the prominent grooves on the surface of the human brain.) The precentral sulcus divides the inferior, midd ... behind. Additional images File:Middle frontal gyrus animation small.gif, Position of middle frontal gyrus (shown in red). File:Gray725 middle frontal gyrus.png, Left cerebral hemisphere seen from above. File:Gray726 middle frontal gyrus.png, Lateral ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Superior Frontal Gyrus
In neuroanatomy, the superior frontal gyrus (SFG, also marginal gyrus) is a gyrus – a ridge on the brain's cerebral cortex – which makes up about one third of the frontal lobe. It is bounded laterally by the superior frontal sulcus. The superior frontal gyrus is one of the frontal gyri. Function Self-awareness In fMRI experiments, Goldberg ''et al.'' have found evidence that the superior frontal gyrus is involved in self-awareness, in coordination with the action of the sensory system. Laughter In 1998, neurosurgeon Itzhak Fried described a 16-year-old female patient (referred to as "patient AK") who laughed when her SFG was stimulated with electric current during treatment for epilepsy. Electrical stimulation was applied to the cortical surface of AK's left frontal lobe while an attempt was made to locate the focus of her epileptic seizures (which were never accompanied by laughter). Fried identified a 2 cm by 2 cm area on the left SFG where stimulation produ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Orbital Part Of Inferior Frontal Gyrus
The orbital part of inferior frontal gyrus also known as the pars orbitalis is the orbital part of the inferior frontal gyrus. In humans, this region is bordered by the triangular part of the inferior frontal gyrus (pars triangularis) and, surrounding the anterior horizontal limb of the lateral sulcus, a portion of the opercular part of inferior frontal gyrus (pars opercularis). Bounded caudally by the anterior ascending limb of the lateral sulcus, it borders on the insula in the depth of the lateral sulcus. It is bordered anteriorly/inferiorly by the lateral orbital sulcus. Cytoarchitectonically it is most closely represented by Brodmann area 47 (BA47).Brodmann, K. (1909). Vergleichende Lokalisationslehre der Grosshirnrinde in ihren Prinzipien dargestellt auf Grund des Zellenbaues. Leipzig, Germany: Barth. However, BA47 and pars orbitalis are not synonymous, as pars orbitalis specifically refers to a grossly visible gyral region and BA47 refers to the cytoarchitectonic fea ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Brodmann Area 45
Brodmann area 45 (BA45), is part of the frontal cortex in the human brain. It is situated on the lateral surface, inferior to BA9 and adjacent to BA46. This area in humans occupies the triangular part of inferior frontal gyrus (H) and, surrounding the anterior horizontal limb of the lateral sulcus (H), a portion of the orbital part of the inferior frontal gyrus (H). Bounded caudally by the anterior ascending limb of the lateral sulcus (H), it borders on the insula in the depth of the lateral sulcus. In terms of cytoarchitecture, it is bounded caudally by the opercular part of inferior frontal gyrus ( Brodmann area 44 (BA44)), rostrodorsally by the middle frontal area 46 (BA46), and ventrally by the orbital part of inferior frontal gyrus (Brodmann area 47 BA47). Functions The left-hemisphere Brodmann area 44 and Brodmann area 45 make up Broca's area, a region that is active in semantic tasks, such as semantic decision tasks (determining whether a word represents an abstrac ... [...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 for the br ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gyrification
Gyrification is the process of forming the characteristic folds of the cerebral cortex. The peak of such a fold is called a ''gyrus'' (pl. ''gyri''), and its trough is called a '' sulcus'' (pl. ''sulci''). The neurons of the cerebral cortex reside in a thin layer of gray matter, only 2–4 mm thick, at the surface of the brain. Much of the interior volume is occupied by white matter, which consists of long axonal projections to and from the cortical neurons residing near the surface. Gyrification allows a larger cortical surface area and hence greater cognitive functionality to fit inside a smaller cranium. In most mammals, gyrification begins during fetal development. Primates, cetaceans, and ungulates have extensive cortical gyri, with a few species exceptions, while rodents generally have none. Gyrification in some animals, for example the ferret, continues well into postnatal life. Gyrification during human brain development As fetal development proceeds, gy ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Brodmann Area 44
Brodmann area 44, or BA44, is part of the frontal Front may refer to: Arts, entertainment, and media Films * ''The Front'' (1943 film), a 1943 Soviet drama film * ''The Front'', 1976 film Music *The Front (band), an American rock band signed to Columbia Records and active in the 1980s and ea ... cerebral cortex, cortex in the human brain. Situated just anterior to premotor cortex (Brodmann area 6, BA6) and on the lateral surface, inferior to Brodmann area 9, BA9. This area is also known as pars opercularis (of the inferior frontal gyrus), and it refers to a subdivision of the cytoarchitecture, cytoarchitecturally defined frontal region of cerebral cortex. In the human it corresponds approximately to the Inferior frontal gyrus#Structure, opercular part of the inferior frontal gyrus. Thus, it is bounded caudally by the inferior precentral sulcus (H) and rostrally by the anterior ascending limb of lateral sulcus (H). It surrounds the diagonal sulcus (H). In the depth of the la ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sulcus (neuroanatomy)
In neuroanatomy, a sulcus (Latin: "furrow", pl. ''sulci'') is a depression or groove in the cerebral cortex. It surrounds a gyrus (pl. gyri), creating the characteristic folded appearance of the brain in humans and other mammals. The larger sulci are usually called fissures. Structure Sulci, the grooves, and gyri, the folds or ridges, make up the folded surface of the cerebral cortex. Larger or deeper sulci are termed fissures, and in many cases the two terms are interchangeable. The folded cortex creates a larger surface area for the brain in humans and other mammals. When looking at the human brain, two-thirds of the surface are hidden in the grooves. The sulci and fissures are both grooves in the cortex, but they are differentiated by size. A sulcus is a shallower groove that surrounds a gyrus. A fissure is a large furrow that divides the brain into lobes and also into the two hemispheres as the longitudinal fissure. Importance of expanded surface area As the sur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sulcus (neuroanatomy)
In neuroanatomy, a sulcus (Latin: "furrow", pl. ''sulci'') is a depression or groove in the cerebral cortex. It surrounds a gyrus (pl. gyri), creating the characteristic folded appearance of the brain in humans and other mammals. The larger sulci are usually called fissures. Structure Sulci, the grooves, and gyri, the folds or ridges, make up the folded surface of the cerebral cortex. Larger or deeper sulci are termed fissures, and in many cases the two terms are interchangeable. The folded cortex creates a larger surface area for the brain in humans and other mammals. When looking at the human brain, two-thirds of the surface are hidden in the grooves. The sulci and fissures are both grooves in the cortex, but they are differentiated by size. A sulcus is a shallower groove that surrounds a gyrus. A fissure is a large furrow that divides the brain into lobes and also into the two hemispheres as the longitudinal fissure. Importance of expanded surface area As the sur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
