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Internal Granular Layer
The internal granular layer of the cerebral cortex, also commonly referred to as the granular layer of the cortex, is the layer IV in the subdivision of the mammalian cerebral cortex into 6 layers. The adjective internal is used in opposition to the external granular layer of the cortex, the term granular refers to the granule cells found here. This layer receives the afferent connections from the thalamus and from other cortical regions and sends connections to the other layers. The line of Gennari (occipital stripe) is also present in this layer. See also * Granular layer * External granular layer (cerebral cortex) The external granular layer of the cerebral cortex is commonly known as layer II. It is different from the internal granular layer of the cerebral cortex (commonly known as layer IV). Layer II is often grouped together with layer III and referr ... Cerebral cortex {{neuroanatomy-stub ... [...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] |
External Granular Layer (cerebral Cortex)
The external granular layer of the cerebral cortex is commonly known as layer II. It is different from the internal granular layer of the cerebral cortex (commonly known as layer IV). Layer II is often grouped together with layer III and referred to as layer II/III. Layers I, II, and III are together referred to as the supragranular layers, because they are above layer IV. Brodmann has this to say about layer II: "The most inconstant or variable layers are Meynert's two so-called granular layers, layers II and IV of the basic pattern (the outer and inner granular layers). They alter their original cytoarchitectonic features so extensively during ontogeny that it is often only possible to correlate their mature structure with their primitive tectogenetic form by following the whole developmental sequence. Extreme variation, such as the disappearance or doubling of layers that we have already discussed, occur particularly in them, and their specific organisation also varies w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Granule Cell
The name granule cell has been used for a number of different types of neurons whose only common feature is that they all have very small cell bodies. Granule cells are found within the granular layer of the cerebellum, the dentate gyrus of the hippocampus, the superficial layer of the dorsal cochlear nucleus, the olfactory bulb, and the cerebral cortex. Cerebellar granule cells account for the majority of neurons in the human brain. These granule cells receive excitatory input from mossy fibers originating from pontine nuclei. Cerebellar granule cells project up through the Purkinje layer into the molecular layer where they branch out into parallel fibers that spread through Purkinje cell dendritic arbors. These parallel fibers form thousands of excitatory granule-cell–Purkinje-cell synapses onto the intermediate and distal dendrites of Purkinje cells using glutamate as a neurotransmitter. Layer 4 granule cells of the cerebral cortex receive inputs from the thala ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Afferent Nerve Fiber
Afferent nerve fibers are axons (nerve fibers) of sensory neurons that carry sensory information from sensory receptors to the central nervous system. Many afferent projections ''arrive'' at a particular brain region. In the peripheral nervous system, afferent nerve fibers are part of the sensory nervous system and arise from outside of the central nervous system. Sensory and mixed nerves contain afferent fibers. Structure Afferent neurons are pseudounipolar neurons that have a single process leaving the cell body dividing into two branches: the long one towards the sensory organ, and the short one toward the central nervous system (e.g. spinal cord). These cells do have sensory afferent dendrites, similar to those typically inherent in neurons. They have a smooth and rounded cell body located in the ganglia of the peripheral nervous system. Just outside the spinal cord, thousands of afferent neuronal cell bodies are aggregated in a swelling in the dorsal root known a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thalamus
The thalamus (: thalami; from Greek language, Greek Wikt:θάλαμος, θάλαμος, "chamber") is a large mass of gray matter on the lateral wall of the third ventricle forming the wikt:dorsal, dorsal part of the diencephalon (a division of the forebrain). Nerve fibers project out of the thalamus to the cerebral cortex in all directions, known as the thalamocortical radiations, allowing hub (network science), hub-like exchanges of information. It has several functions, such as the relaying of sensory neuron, sensory and motor neuron, motor signals to the cerebral cortex and the regulation of consciousness, sleep, and alertness. Anatomically, the thalami are paramedian symmetrical structures (left and right), within the vertebrate brain, situated between the cerebral cortex and the midbrain. It forms during embryonic development as the main product of the diencephalon, as first recognized by the Swiss embryologist and anatomist Wilhelm His Sr. in 1893. Anatomy The thalami ar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Line Of Gennari
The line of Gennari (also called the "band" or "stria" of Gennari) is a band of myelinated axons that runs parallel to the surface of the cerebral cortex on the banks of the calcarine fissure in the occipital lobe. This formation is visible to the naked eye as a white strip running through the cortical grey matter, and is the reason the V1 in primates is also referred to as the "striate cortex." The line of Gennari is due to dense axonal input from the thalamus to layer IV of visual cortex. It is the name given to the enlarged external band of Baillarger. The structure is named for its discoverer, Francesco Gennari, who first observed it in 1776 as a medical student at the University of Parma. He described it in a book which he published in 1782. Although non-primate species have areas that are designated primary visual cortex, some (if not all) lack a stria of Gennari. Vicq d’Azyr published the stripes in ''Traité d'anatomie'' (1786), and for a while it was known as the ''s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Granular Layer (other)
Granular layer may refer to: * Internal granular layer and External granular layer (cerebral cortex) The external granular layer of the cerebral cortex is commonly known as layer II. It is different from the internal granular layer of the cerebral cortex (commonly known as layer IV). Layer II is often grouped together with layer III and referr ... of the cerebral cortex * Granular layer (cerebellum) of the cortex of the human cerebellum * Granular layer of skin * Granular layer of dentate gyrus {{disambiguation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
