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Interneurons
Interneurons (also called internuncial neurons, association neurons, connector neurons, or intermediate neurons) are neurons that are not specifically motor neurons or sensory neurons. Interneurons are the central nodes of neural circuits, enabling communication between sensory or motor neurons and the central nervous system (CNS). They play vital roles in reflexes, neuronal oscillations, and neurogenesis in the adult mammalian brain. Interneurons can be further broken down into two groups: local interneurons and relay interneurons. Local interneurons have short axons and form circuits with nearby neurons to analyze small pieces of information. Relay interneurons have long axons and connect circuits of neurons in one region of the brain with those in other regions. However, interneurons are generally considered to operate mainly within local brain areas. The interaction between interneurons allows the brain to perform complex functions such as learning and decision-making. S ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spinal Interneuron
A spinal interneuron, found in the spinal cord, relays signals between (afferent) sensory neurons, and (efferent) motor neurons. Different classes of spinal interneurons are involved in the process of sensory-motor integration. Most interneurons are found in the grey column, a region of grey matter in the spinal cord. Structure The grey column of the spinal cord appears to have groups of small neurons, often referred to as spinal interneurons, that are neither primary sensory cells nor motor neurons. The versatile properties of these spinal interneurons cover a wide range of activities. Their functions include the processing of sensory input, the modulation of motor neuron activity, the coordination of activity at different spinal levels, and the relay of sensory or proprioceptive data to the brain. There has been extensive research on the identification and characterization of the spinal cord interneurons based on factors such as location, size, structure, connectivity, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neurons
A neuron (American English), neurone (British English), or nerve cell, is an membrane potential#Cell excitability, excitable cell (biology), cell that fires electric signals called action potentials across a neural network (biology), neural network in the nervous system. They are located in the nervous system and help to receive and conduct impulses. Neurons communicate with other cells via synapses, which are specialized connections that commonly use minute amounts of chemical neurotransmitters to pass the electric signal from the presynaptic neuron to the target cell through the synaptic gap. Neurons are the main components of nervous tissue in all Animalia, animals except sponges and placozoans. Plants and fungi do not have nerve cells. Molecular evidence suggests that the ability to generate electric signals first appeared in evolution some 700 to 800 million years ago, during the Tonian period. Predecessors of neurons were the peptidergic secretory cells. They eventually ga ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Parvalbumin
Parvalbumin (PV) is a calcium-binding protein with low molecular weight (typically 9–11 kDa). In humans, it is encoded by the ''PVALB'' gene. It is a member of the albumin family; it is named for its size (''parv-'', from Latin ' which means "small") and its ability to coagulate. It has three EF hand motifs and is structurally related to calmodulin and troponin C. Parvalbumin is found in fast-contracting muscles, where its levels are highest, as well as in the brain and some endocrine tissues. Parvalbumin is a small, stable protein containing EF-hand type calcium binding sites. It is involved in calcium signaling. Typically, this protein is broken into three domains, domains AB, CD and EF, each individually containing a helix-loop-helix motif. The AB domain houses a two amino-acid deletion in the loop region, whereas domains CD and EF contain the N-terminal and C-terminal, respectively. Calcium binding proteins like parvalbumin play a role in many physiological processes, nam ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Golgi Cell
In neuroscience, Golgi cells are the most abundant inhibitory interneurons found within the granular layer of the cerebellum. Golgi cells can be found in the granular layer at various layers. The Golgi cell is essential for controlling the activity of the granular layer. They were first identified as inhibitory in 1964. It was also the first example of an inhibitory feedback network in which the inhibitory interneuron was identified anatomically. Golgi cells produce a wide lateral inhibition that reaches beyond the afferent synaptic field and inhibit granule cells via feedforward and feedback inhibitory loops. These cells synapse onto the dendrite of granule cells and unipolar brush cells. They receive excitatory input from mossy fibres, also synapsing on granule cells, and parallel fibers, which are long granule cell axons. Thereby this circuitry allows for feed-forward and feed-back inhibition of granule cells. Connections The cerebellar network contains a large number of ... [...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] |
Basket Cell
Basket cells are inhibitory GABAergic interneurons of the brain, found throughout different regions of the cortex and cerebellum. Anatomy and physiology Basket cells are multipolar GABAergic interneurons that function to make inhibitory synapses and control the overall potentials of target cells. In general, dendrites of basket cells are free branching, contain smooth spines, and extend from 3 to 9 mm. Axons are highly branched, ranging in total from 20 to 50mm in total length. The branched axonal arborizations give rise to the name as they appear as baskets surrounding the soma of the target cell. Basket cells form axo-somatic synapses, meaning their synapses target somas of other cells. By controlling the somas of other neurons, basket cells can directly control the action potential discharge rate of target cells. Basket cells can be found throughout the brain, in among other the cortex, hippocampus, amygdala, basal ganglia, and the cerebellum. Cortex In the cortex, basket cel ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rexed Laminae
The Rexed laminae (singular: Rexed lamina) comprise a system of ten layers of grey matter (I–X), identified in the early 1950s by Bror Rexed to label portions of the grey columns of the spinal cord. Similar to Brodmann areas, they are defined by their cellular structure rather than by their location, but the location still remains reasonably consistent. Laminae * Posterior grey column: I–VI ** Lamina I: marginal nucleus of spinal cord or posteromarginal nucleus ** Lamina II: substantia gelatinosa of Rolando ** Laminae III and IV: nucleus proprius ** Lamina V: Neck of the dorsal horn. Neurons within lamina V are mainly involved in processing sensory afferent stimuli from cutaneous, muscle and joint mechanical nociceptors as well as visceral nociceptors. This layer is home to wide dynamic range tract neurons, interneurons and propriospinal neurons. Viscerosomatic pain signal convergence often occurs in this lamina due to the presence of wide dynamic range tract neurons resul ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lugaro Cell
Lugaro cells are primary sensory interneurons of the cerebellum, that have an inhibitory function. They are fusiform, having a spindle shape that tapers at each end. They were first described by Ernesto Lugaro in the early 20th century. Lugaro cells are found just beneath the layer of Purkinje cells between the molecular layer and the granular layer. They have thick principal dendrites coming from opposite poles of their bodies. These dendrites are very long and travel along the boundary between the Purkinje layer and the granular layer. They seem to contact from 5 to 15 Purkinje cells in a horizontal direction. They can also sense stimuli close to the Purkinje cells and their dendrites form a large receptive area that monitors the environment near to the Purkinje cells. Whilst their dendrites make contact with the Purkinje cells they also receive inputs from branches of the Purkinje axons by which they seem to have a sampling and integration role.Lainé J, Axelrad H. Lugaro cells ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neuronal Oscillations
Neural oscillations, or brainwaves, are rhythmic or repetitive patterns of neural activity in the central nervous system. Neural tissue can generate oscillatory activity in many ways, driven either by mechanisms within individual neurons or by interactions between neurons. In individual neurons, oscillations can appear either as oscillations in membrane potential or as rhythmic patterns of action potentials, which then produce oscillatory activation of post-synaptic neurons. At the level of neural ensembles, synchronized activity of large numbers of neurons can give rise to macroscopic oscillations, which can be observed in an electroencephalogram. Oscillatory activity in groups of neurons generally arises from feedback connections between the neurons that result in the synchronization of their firing patterns. The interaction between neurons can give rise to oscillations at a different frequency than the firing frequency of individual neurons. A well-known example of macros ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rexed Laminae
The Rexed laminae (singular: Rexed lamina) comprise a system of ten layers of grey matter (I–X), identified in the early 1950s by Bror Rexed to label portions of the grey columns of the spinal cord. Similar to Brodmann areas, they are defined by their cellular structure rather than by their location, but the location still remains reasonably consistent. Laminae * Posterior grey column: I–VI ** Lamina I: marginal nucleus of spinal cord or posteromarginal nucleus ** Lamina II: substantia gelatinosa of Rolando ** Laminae III and IV: nucleus proprius ** Lamina V: Neck of the dorsal horn. Neurons within lamina V are mainly involved in processing sensory afferent stimuli from cutaneous, muscle and joint mechanical nociceptors as well as visceral nociceptors. This layer is home to wide dynamic range tract neurons, interneurons and propriospinal neurons. Viscerosomatic pain signal convergence often occurs in this lamina due to the presence of wide dynamic range tract neurons resul ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stellate Cell
Stellate cells are neurons in the central nervous system, named for their star-like shape formed by dendritic processes radiating from the cell body. These cells play significant roles in various brain functions, including inhibition in the cerebellum and excitation in the cortex, and are involved in synaptic plasticity and neurovascular coupling. Morphology Stellate cells are characterized by their star-shaped dendritic trees. Dendrites can vary between neurons, with stellate cells being either spiny or aspinous. In contrast, pyramidal cells, which are also found in the cerebral cortex, are always spiny and pyramid-shaped. The classification of neurons often depends on the presence or absence of dendritic spines: those with spines are classified as spiny, while those without are classified as aspinous. Types and locations Cerebellar Many stellate cells are GABAergic and are located in the molecular layer of the cerebellum. Most common stellate cells are the inhibito ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Human Brain
The human brain is the central organ (anatomy), organ of the nervous system, and with the spinal cord, comprises the central nervous system. It consists of the cerebrum, the brainstem and the cerebellum. The brain controls most of the activities of the human body, body, processing, integrating, and coordinating the information it receives from the sensory nervous system. The brain integrates sensory information and coordinates instructions sent to the rest of the body. The cerebrum, the largest part of the human brain, consists of two cerebral hemispheres. Each hemisphere has an inner core composed of white matter, and an outer surface – the cerebral cortex – composed of grey matter. The cortex has an outer layer, the neocortex, and an inner allocortex. The neocortex is made up of six Cerebral cortex#Layers of neocortex, neuronal layers, while the allocortex has three or four. Each hemisphere is divided into four lobes of the brain, lobes – the frontal lobe, frontal, pa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
