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Gyri
In neuroanatomy, a gyrus (: gyri) is a ridge on the cerebral cortex. It is generally surrounded by one or more sulcus (neuroanatomy), sulci (depressions or furrows; : 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 Lissencephaly, lissencephalic, meaning 'smooth-brained'. As development continues, gyri and Sulcus (neuroanatomy), ... [...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 (neuroanatomy), 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 prenatal development, fetal development. Primates, cetaceans, and ungulates have extensive cortical gyri, with a few species exceptions, while small rodents such as the rat, and mouse have none. Gyrification in some animals, for example the ferret, continues well into postnatal life. Human brain devel ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gyri
In neuroanatomy, a gyrus (: gyri) is a ridge on the cerebral cortex. It is generally surrounded by one or more sulcus (neuroanatomy), sulci (depressions or furrows; : 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 Lissencephaly, lissencephalic, meaning 'smooth-brained'. As development continues, gyri and Sulcus (neuroanatomy), ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sulcus (neuroanatomy)
In neuroanatomy, a sulcus (Latin: "furrow"; : sulci) is a shallow Sulcus (morphology), depression or groove in the cerebral cortex. One or more sulci surround a gyrus (pl. gyri), a ridge on the surface of the cortex, creating the characteristic folded appearance of the brain in humans and most other mammals. The larger sulci are also called Sulcus (morphology)#Brain, fissures. The cortex develops in the fetal stage of corticogenesis, preceding the cortical folding stage known as gyrification. The large fissures and main sulci are the first to develop. Mammals that have a folded cortex are known as ''gyrencephalic'', and the small-brained mammals that have a smooth cortex, such as rats and mice are termed lissencephaly, lissencephalic. Structure Sulci, the grooves, and gyri, the folds or ridges, make up the gyrification, folded surface of the cerebral cortex. Larger or deeper sulci are also often termed fissures. The folded cortex creates a larger surface area for the brain in h ... [...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. It is the largest site of Neuron, neural integration in the central nervous system, and plays a key role in attention, perception, awareness, thought, memory, language, and consciousness. The six-layered neocortex makes up approximately 90% of the Cortex (anatomy), cortex, with the allocortex making up the remainder. The cortex is divided into left and right parts by the longitudinal fissure, which separates the two cerebral hemispheres that are joined beneath the cortex by the corpus callosum and other commissural fibers. 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 neurocranium, cranium. Apart from minimising brain and cranial volume, gyrification, cortical folding is crucial for the Neural circuit, brain circuitry ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sulcus (neuroanatomy)
In neuroanatomy, a sulcus (Latin: "furrow"; : sulci) is a shallow Sulcus (morphology), depression or groove in the cerebral cortex. One or more sulci surround a gyrus (pl. gyri), a ridge on the surface of the cortex, creating the characteristic folded appearance of the brain in humans and most other mammals. The larger sulci are also called Sulcus (morphology)#Brain, fissures. The cortex develops in the fetal stage of corticogenesis, preceding the cortical folding stage known as gyrification. The large fissures and main sulci are the first to develop. Mammals that have a folded cortex are known as ''gyrencephalic'', and the small-brained mammals that have a smooth cortex, such as rats and mice are termed lissencephaly, lissencephalic. Structure Sulci, the grooves, and gyri, the folds or ridges, make up the gyrification, folded surface of the cerebral cortex. Larger or deeper sulci are also often termed fissures. The folded cortex creates a larger surface area for the brain in h ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lissencephaly
Lissencephaly (, meaning 'smooth brain') is a set of rare brain disorders whereby the whole or parts of the surface of the brain are smooth. It is caused by defective neuronal migration during the 12th to 24th weeks of gestation, resulting in a lack of development of brain folds (gyri) and grooves (sulci). It is a form of cephalic disorder. Terms such as ''agyria'' (no gyri) and '' pachygyria'' (broad gyri) are used to describe the appearance of the surface of the brain. Children with lissencephaly generally have significant developmental delays, but these vary greatly from child to child depending on the degree of brain malformation and seizure control. Life expectancy can be shortened, generally due to respiratory problems. Signs and symptoms Affected children display severe psychomotor impairment, failure to thrive, seizures, and muscle spasticity or hypotonia. Other symptoms of the disorder may include unusual facial appearance, difficulty swallowing, and anomalies of ... [...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 The inferior frontal gyrus (IFG; also 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 ... (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 Grosshirnrind ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Inferior Frontal Gyrus
The inferior frontal gyrus (IFG; also 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 ... [...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 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. It is the largest site of Neuron, neural integration in the central nervous system, and plays .... 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 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 surface of left ... [...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. The medial frontal gyrus (MFG) is the medial portion of the superior frontal gyrus. The MFG plays a crucial role implicated in self-reflection and self-awareness, particularly during self-referential processing. The MFG becomes activated when individuals engage in tasks that involve evaluating traits about themselves. This process is essential for maintaining a sense of self. In this study, people with major depressive disorder, also known as MDD, showed heightened and broader activati ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lissencephaly
Lissencephaly (, meaning 'smooth brain') is a set of rare brain disorders whereby the whole or parts of the surface of the brain are smooth. It is caused by defective neuronal migration during the 12th to 24th weeks of gestation, resulting in a lack of development of brain folds (gyri) and grooves (sulci). It is a form of cephalic disorder. Terms such as ''agyria'' (no gyri) and '' pachygyria'' (broad gyri) are used to describe the appearance of the surface of the brain. Children with lissencephaly generally have significant developmental delays, but these vary greatly from child to child depending on the degree of brain malformation and seizure control. Life expectancy can be shortened, generally due to respiratory problems. Signs and symptoms Affected children display severe psychomotor impairment, failure to thrive, seizures, and muscle spasticity or hypotonia. Other symptoms of the disorder may include unusual facial appearance, difficulty swallowing, and anomalies of ... [...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 area 22, 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 si ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
