The uniting character is the nervous system organization with a circumpharyngeal brain and somata–neuropil–somata pattern.The neuromuscular system of Pycnophyes kielensis (Kinorhyncha: Allomalorhagida) investigated by confocal laser scanning microscopy - EvoDevo The name derives from the position of the brain around the pharynx.
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Morphological features of antillatoxin-induced neuronal toxicity are swelling of neuronal somata, thinning of neurites and blebbing of neurite membranes.
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The positioning of Kenyon cells depends on their birth order. The somata of early-born Kenyon cells are pushed outward as more Kenyon cells are created. This results in a concentric pattern of cell bodies, with the somata of the last-born cells in the center, where the neuroblast had been, and the somata of the first-born cells at the outermost margins of the cell body area. Where a Kenyon cell sends its dendrites in the calyces and which lobes it projects its axons to varies based on its birth-order.
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Additionally, it has been shown that PMCA activity is modulated and partly powered by glycolysis in neuronal somata and dendrites. Presumably, it is due to PMCA proximity to glucose transporters in the plasma membrane.
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Neochildia fusca is a dark brown acoel of the family Convolutidae, first scientifically described by Louise Bush in 1975. The nervous system is composed of an anterior compact brain organized as a layer of neural somata surrounding a central neuropil free of cell bodies.
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The nest basket cells are an intermediate form of the small and large cells, their axons are confined mainly to the same cortical layer as their somata. Nest basket cells have "radiating axonal collaterals" between that of large and small basket cells. They are included as basket cells because they are interneurons that perform axo-somatic synapses.
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Therefore, the SGC sheath of sympathetic neurons must extend even further to cover the axon hillock near the somata. Like the regions of the sheath near the glial nucleus, the regions of the sheath at the axon hillocks are thicker than those surrounding the rest of the neuron. This indicates that the SGCs play a role in the synaptic environment, thereby influencing synaptic transmission.
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Yet those same oscillations propagate far into the surrounding tissue in the manner of a Type 1 excitable medium. Nonetheless, it remains difficult to target opsin to defined subcellular compartments, e.g. the plasma membrane, synaptic vesicles, or mitochondria. Restricting the opsin to specific regions of the plasma membrane such as dendrites, somata or axon terminals would provide a more robust understanding of neuronal circuitry.
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Hippocampal basket cells target somata and proximal dendrites of pyramidal neurons. Similar to their counterparts in the cortex, hippocampal basket cells are also parvalbumin- expressing and fast-spiking. In the CA3 region of the hippocampus, basket cells can often form recurrent inhibition loops with pyramidal cells. Projections from a pyramidal cell will innervate the basket cell, which in turn has a projection back onto the original pyramidal cells.
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A sea hare There have been numerous studies of learning and memory using nociceptors in the sea hare, Aplysia. Many of these have focused on mechanosensory neurons innervating the siphon and having their somata (bulbous end) in the abdominal ganglion (LE cells). These LE cells display increasing discharge to increasing pressures, with maximal activation by crushing or tearing stimuli that cause tissue injury. Therefore, they satisfy accepted definitions of nociceptors.
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Mitochondria play a central role in maintaining the life cycle of retinal ganglion cells because of their high energy dependence. Mitochondria are made within the central somata of the retinal ganglion cell, transported down axons, and distributed where they are needed. Genetic mutations in mitochondrial DNA, vitamin depletion, alcohol and tobacco abuse, and use of certain drugs can cause derangements in efficient transport of mitochondria, which can cause a primary or secondary optic neuropathy.
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To be specific, it is found in the somata and dendrites of dopaminergic neurons in the ventral tegmental area (VTA) and the substantia nigra. Some studies implicate this pathway as having a role in attention deficiency and hyperactive behavior. Soluble guanylate cyclase contains a molecule of heme, and is activated primarily by the binding of nitric oxide (NO) to that heme. sGC is primary receptor for NO a gaseous, membrane-soluble neurotransmitter.
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Radial glial cells, or radial glial progenitor cells (RGPs), are bipolar- shaped progenitor cells that are responsible for producing all of the neurons in the cerebral cortex. RGPs also produce certain lineages of glia, including astrocytes and oligodendrocytes. Their cell bodies (somata) reside in the embryonic ventricular zone, which lies next to the developing ventricular system. During development, newborn neurons use radial glia as scaffolds, traveling along the radial glial fibers in order to reach their final destinations.
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A higher volume of penumbra around a cerebral infarction means a greater volume of potentially salvageable brain matter by thrombolysis and thrombectomy. Such therapies have a greater effect on regaining functions such as movement after a cerebral infarction. In the penumbra, microglia are thought to exert neuroprotective effects via specialized contacts with neuronal somata, termed somatic junctions. Understanding and supporting these microglial actions could broaden the therapeutic window and lead to higher amount of preserved nervous tissue.
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In the cortex, basket cells have sparsely branched axons giving off small pericellular, basket-shaped elaborations at several intervals along their length. Basket cells make up 5-10% of total neurons in the cortex. There are three types of basket cells in the cortex, the small, large and nest type: The axon of a small basket cell arborizes in the vicinity of that same cell's dendritic range, this axon is short. In contrast, large basket cells innervate somata in different cortical columns due to a long axon.
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While the neuroprotective effects of Epo administration in models of brain injury and disease have been well described, the effects of Epo on Neuroregeneration are currently being investigated. Epo administration during optic nerve transaction was used to assess the neuroprotective properties in vivo as well as demonstrate the neuroregenerative capabilities. The intravitreal injection of Epo increased retinal ganglion cell somata and axon survival after transaction. A small amount of axons penetrated the transaction site and regenerated up to 1 mm into the distal nerve.
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In 1891 Santiago Ramón y Cajal described slender horizontal bipolar cells he had found in an histological preparation of the developing marginal zone of lagomorphs. These cells were then considered by Gustaf Retzius as homologous to the ones he had found in the marginal zone of human fetuses around mid-gestation in 1893 and 1894. He described those cells as having large, horizontal, sometimes vertically orientated somata located at some distance from the pia. Later on in 1899, Cajal drew the neurons in layer I of the human fetus at term and newborn.
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Following the completion of his Ph.D., he became interested in how calcium entered neurons, and began a post-doctoral fellowship with Dan Johnston. In this period he showed for the first time, using calcium imaging, that different types of voltage-gated calcium channels were not distributed homogeneously throughout neuron dendrites and somata. Moreover, he was able to show that certain types of voltage-gated channels played a preferential role in long-term forms of synaptic depression, or LTD. Despite lasting only 2.5 years, this post-doctoral fellowship generated 8 publications.
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Grohmann, L., Blenau, W., Erber, J., Ebert, P. R., Strünker, T., & Baumann, A. (2003). Molecular and functional characterization of an octopamine receptor from honeybee (Apis mellifera) brain. Journal of Neurochemistry, 86(3), 725-735 Influencing this signal transduction system can lead to various events depending on the celltype. Since it has been discovered that the octopamine receptor coding gene is expressed on very high rates in the somata of the honeybee brain, it is suggested that it is involved in the processing of sensory inputs, antennal motor outputs and higher-order brain functions.
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Satellite glial cells in sensory ganglia are laminar cells that most often an envelope of multiple SGCs completely surrounds each sensory neuron. The number of SGCs that make up the sheath increases proportionately with the volume of the neuron which it surrounds. Additionally, the volume of the sheath itself increases proportionately with the volume and surface area of the neuron's somata. The distance of extracellular space between the sheath and the neuronal plasma membrane measures , allowing the neuron and its SGC sheath to form a single anatomical and functional unit.
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Inhibitory postsynaptic potentials can be inhibited themselves through a signaling process called "depolarized-induced suppression of inhibition (DSI)" in CA1 pyramidal cells and cerebellar Purkinje cells. In a laboratory setting step depolarizations the soma have been used to create DSIs, but it can also be achieved through synaptically induced depolarization of the dendrites. DSIs can be blocked by ionotropic receptor calcium ion channel antagonists on the somata and proximal apical dendrites of CA1 pyramidal cells. Dendritic inhibitory postsynaptic potentials can be severely reduced by DSIs through direct depolarization.
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Microscopic studies show that the Fañanas cell represents a satellite glial cell whose protrusions do not contain glial filaments like GFAP. They are located near the somata of Purkinje cells in the granular layer. With regard to the typical "feathered" microscopic structure of the cells, Fañanas glial cells occur in subforms with one, two or multiple "feathers" of cytoplasmatic extensions, that are studded with small, rounded sprouts. The protrusions are often much shorter than those of other Golgi epithelial cells and run parallel to the fibres of the Bergmann glial cells.
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KCC2 is a neuron-specific membrane protein expressed throughout the central nervous system, including the hippocampus, hypothalamus, brainstem, and motoneurons of the ventral spinal cord. At the subcellular level, KCC2 has been found in membranes of the somata and dendrites of neurons, with no evidence of expression on axons. KCC2 has also been shown to colocalize with GABAA receptors, which serve as ligand-gated ion channels to allow chloride ion movement across the cell membrane. Under normal conditions, the opening of GABAA receptors permits the hyperpolarizing influx of chloride ions to inhibit postsynaptic neurons from firing.
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Nearly all neurons are stained for GABA, especially in the central part of the nucleus, and the remaining GABA negative cells are interspersed with the positive, and often stain for glycine. Two populations of GABA+ cells are visible: larger, lightly stained cells that project to the contralateral IC, and smaller, darker stained cells that project ipsilaterally. GABAergic axon terminals form dense groups surrounded by GABA-lemniscal fibers throughout the nucleus, and synapse on both somata and in the neuropil. Glycinergic axon terminals, on the other hand, are more finely localized, with the majority of recipient neurons located laterally in the nucleus.
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In addition, electrical activity between action potentials in the optic nerve and the firing of the BRNs were shown to share a 1:1 correlation. In 1984, McMahon also demonstrated that the surgical removal of the photoreceptor layer failed to disrupt circadian rhythm in the Bulla eye, while the removal of the BRNs abolished circadian rhythm. His discovery that a fragment of Bulla retina containing as few as six intact BRN somata were sufficient for circadian rhythmogenesis further supported the BRNs as circadian pacemakers. Later work by Dr. Stephan Michel using a surgical reductionist approach provided further evidence that isolated BRNs were capable of circadian oscillations in their conductance.
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What is described above concerned the input map or "inmap" (corresponding to the spatial distribution of the afferent axons from one source to one target). This does not correspond necessarily to the output map or outmap (corresponding to the distribution of the neurons in relation to their axonal targets). Physiological studies and transsynaptic viral markers have shown that islands of pallidal neurons (only their cell bodies or somata, or trigger points) sending their axons through their particular thalamic territories (or nuclei) to one determined cortical target are organized into radial bands.Hoover and Strick 1994Middleton and Strick, 1994 These were assested to be totally representative of the pallidal organisation.
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Aspiny neurons, the second class of neurons found in the stratum lucidum, are another type of inhibitory cell similar to spiny neurons, though lacking dendrite projections. They make up the majority of the neuron composition in comparison to spiny neurons, about 63 percent. The somata of aspiny neurons are for the most part bipolar, generating 2–5 primary dendrites "that to a varying extent displayed varicose swellings in their course". Similar to spiny neurons, aspiny neuron dendrites "branch extensively in stratum lucidum and stratum radiatum of CA3", in contrast to spiny neurons, however, some dendrites "traversed stratum pyramidale and entered stratum oriens", the second deepest layer of the hippocampus.
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Mitral cells are a neuronal cell type in the mammalian olfactory bulb, distinguished by the position of their somata located in an orderly row in the mitral cell layer of the bulb. They typically have a single primary dendrite, which they project into a single glomerulus in the glomerular layer, and a few lateral dendrites that project laterally in the external plexiform layer. Mitral cells are closely related to the second type of projection neuron in the mammalian bulb, known as the tufted cell. In lower vertebrates, mitral and tufted cells cannot be morphologically distinguished from tufted cells, and their morphology is substantially different from the mammalian mitral cells.
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The cells laid closer to the pia and displayed smaller, often triangular or pyriform somata, and less complex processes that lacked the ascending branchlets and had a more superficial location than the cells Retzius previously described, The cells' different morphologies and the fact that Cajal and Retzius used different species at different developmental periods led to discussion about the definition of Cajal–Retzius cells. In fact immunohistochemical studies performed at advanced developmental stages in human and macaque cortex visualize cells more similar to the cells Cajal described. In contrast, studies from 1994 of the human mid- gestation period describe cells closer to the Retzius type. The early descriptions by Cajal and Retzius referred to the neocortex, but since 1994 similar cells have been found in the marginal zone of the hippocampus.
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The secondary layer (Layer II) provides for a hypocellular gap abutting the former and has been shown to contain a network of functionally correlated Glial Fibrillary Acid Protein (GFAP)-positive astrocytic processes that are linked to junctional complexes, yet lack cell bodies except for the rare neuronal somata. While the function of this layer is yet unknown in humans, it has been hypothesized that the astrocytic and ependymal interconnections of Layer I and II may act to regulate neuronal functions, establish metabolic homeostasis, and/or control neuronal stem cell proliferation and differentiation during development. Potentially, such characteristics of the layer may act as a remainder of early developmental life or pathway for cellular migration given similarity to a homologous layer in bovine SVZ shown to have migratory cells common only to higher order mammals.
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