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However, other ions such as calcium may be important and there is a great diversity of channels for all ions. As an example, the cardiac action potential illustrates how differently shaped action potentials can be generated on membranes with voltage-sensitive calcium channels and different types of sodium/potassium channels. The second type of mathematical model is a simplification of the first type; the goal is not to reproduce the experimental data, but to understand qualitatively the role of action potentials in neural circuits. | https://en.wikipedia.org/wiki/Quantitative_models_of_the_action_potential |
For such a purpose, detailed physiological models may be unnecessarily complicated and may obscure the "forest for the trees". The FitzHugh–Nagumo model is typical of this class, which is often studied for its entrainment behavior. Entrainment is commonly observed in nature, for example in the synchronized lighting of fireflies, which is coordinated by a burst of action potentials; entrainment can also be observed in individual neurons. Both types of models may be used to understand the behavior of small biological neural networks, such as the central pattern generators responsible for some automatic reflex actions. Such networks can generate a complex temporal pattern of action potentials that is used to coordinate muscular contractions, such as those involved in breathing or fast swimming to escape a predator. | https://en.wikipedia.org/wiki/Quantitative_models_of_the_action_potential |
In neuropsychology, linguistics, and philosophy of language, a natural language or ordinary language is any language that occurs naturally in a human community by a process of use, repetition, and change without conscious planning or premeditation. It can take different forms, namely either a spoken language or a sign language. Natural languages are distinguished from constructed and formal languages such as those used to program computers or to study logic. | https://en.wikipedia.org/wiki/Natural_language |
In neuropsychopharmacology, uncoupling, also known as decoupling, is the process of receptor- or ligand-binding sites or domains becoming separated, moving alignments and/or becoming internalised as a result of drug tolerance resulting from prolonged exposure to bioavailable psychoactive substances or toxins. == References == | https://en.wikipedia.org/wiki/Uncoupling_(neuropsychopharmacology) |
In neuroscience and anatomy, nodes of Ranvier ( RAHN-vee-ay), also known as myelin-sheath gaps, occur along a myelinated axon where the axolemma is exposed to the extracellular space. Nodes of Ranvier are uninsulated and highly enriched in ion channels, allowing them to participate in the exchange of ions required to regenerate the action potential. Nerve conduction in myelinated axons is referred to as saltatory conduction (from Latin saltus 'leap, jump') due to the manner in which the action potential seems to "jump" from one node to the next along the axon. This results in faster conduction of the action potential. | https://en.wikipedia.org/wiki/Myelin_sheath_gap |
In neuroscience and computer science, synaptic weight refers to the strength or amplitude of a connection between two nodes, corresponding in biology to the amount of influence the firing of one neuron has on another. The term is typically used in artificial and biological neural network research. | https://en.wikipedia.org/wiki/Synaptic_weight |
In neuroscience and motor control , the degrees of freedom problem or motor equivalence problem states that there are multiple ways for humans or animals to perform a movement in order to achieve the same goal. In other words, under normal circumstances, no simple one-to-one correspondence exists between a motor problem (or task) and a motor solution to the problem. The motor equivalence problem was first formulated by the Russian neurophysiologist Nikolai Bernstein: "It is clear that the basic difficulties for co-ordination consist precisely in the extreme abundance of degrees of freedom, with which the centre is not at first in a position to deal. | https://en.wikipedia.org/wiki/Degrees_of_freedom_problem |
"Although the question of how the nervous system selects which particular degrees of freedom (DOFs) to use in a movement may be a problem to scientists, the abundance of DOFs is almost certainly an advantage to the mammalian and the invertebrate nervous systems. The human body has redundant anatomical DOFs (at muscles and joints), redundant kinematic DOFs (movements can have different trajectories, velocities, and accelerations and yet achieve the same goal), and redundant neurophysiological DOFs (multiple motoneurons synapsing on the same muscle, and vice versa). How the nervous system "chooses" a subset of these near-infinite DOFs is an overarching difficulty in understanding motor control and motor learning. | https://en.wikipedia.org/wiki/Degrees_of_freedom_problem |
In neuroscience and neurology, a trigger zone is an area in the body, or of a cell, in which a specific type of stimulation triggers a specific type of response. The term was first used in this context around 1914 by Hugh T. Patrick, who was writing about trigeminal neuralgia, a condition in which pain fibers in the trigeminal nerve become hypersensitive. In people with trigeminal neuralgia, even a light touch to some part of the body—often a tooth or a part of the face—can give rise to an extended period of excruciating pain. Patrick referred to the sensitive part of the body as the "dolorogenic zone", and used the term "trigger zone" as a simpler equivalent. | https://en.wikipedia.org/wiki/Trigger_zone |
Through the 1920s and 1930s the term came into steadily wider use, but almost always in the context of neuralgia.Starting in the late 1930s, other types of stimulation and other types of responses were characterized as having the properties of a trigger zone. In 1940, for example, Morison and Dempsey observed that a small area of the cerebral cortex could be triggered when electrical stimulation would evoke widespread activity in other parts of the cerebral cortex. In 1944 Paul Wilcox described triggering of epileptic seizure by electrical stimulation of another area of the cerebral cortex.The chemoreceptor trigger zone is within the area postrema of the medulla oblongata in which many types of chemical stimulation can provoke nausea and vomiting. | https://en.wikipedia.org/wiki/Trigger_zone |
This area was first identified and named in 1951 by Herbert L. Borison and Kenneth R. Brizzee.Parts of cells, rather than parts of the body, can also behave as trigger zones. The axon hillock of a neuron possesses the highest density of voltage-gated Na+ channels, and is therefore the region where it is easiest for the action potential threshold to be reached. == References == | https://en.wikipedia.org/wiki/Trigger_zone |
In neuroscience and psychophysics, an absolute threshold was originally defined as the lowest level of a stimulus – light, sound, touch, etc. – that an organism could detect. Under the influence of signal detection theory, absolute threshold has been redefined as the level at which a stimulus will be detected a specified percentage (often 50%) of the time. The absolute threshold can be influenced by several different factors, such as the subject's motivations and expectations, cognitive processes, and whether the subject is adapted to the stimulus.The absolute threshold can be compared to the difference threshold, which is the measure of how different two stimuli must be for the subject to notice that they are not the same. | https://en.wikipedia.org/wiki/Absolute_threshold |
In neuroscience the bridge locus for a particular sensory percept is a hypothetical set of neurons whose activity is the basis of that sensory percept. The term was introduced by D.N. Teller and E.Y. Pugh Jr. | https://en.wikipedia.org/wiki/Bridge_locus |
in 1983, and has been sparingly used. Activity in the bridge locus neurons is postulated to be necessary and sufficient for sensory perception: if the bridge locus neurons are not active, then the sensory perception does not occur, regardless of the actual sensory input. Conversely if the bridge locus neurons are active, then sensory perception occurs, regardless of the actual sensory input. | https://en.wikipedia.org/wiki/Bridge_locus |
It is the highest neural level of a sensory perception. So, for example, retinal neurons are not considered a bridge locus for visual perception because stimulating visual cortex can give rise to visual percepts.Not all scholars believe in such a neural correlate of consciousness. Pessoa et al., for example, argue that there is no necessity for a bridge locus, basing their argument on the requirement of an isomorphism between neural states and conscious states. | https://en.wikipedia.org/wiki/Bridge_locus |
Thompson argues that there are good reasons to think that the notion of a bridge locus, which he calls a "localizationist approach", is misguided, questioning the premise that there has to be one particular neural stage whose activity forms the immediate substrate of perception. He argues, based upon work by Zeki & Shipp, DeYoe & Van Essen, and others, that brain regions are not independent stages or modules but have dense forward and backward projections that act reciprocally, and that visual processing is highly interactive and context-dependent. He also argues that cells in the visual cortex "are not mere 'feature detectors'", and that neuroscience has revealed that the brain in fact employs distributed networks, rather than centralized representations. He equates the notion of a bridge locus to a Cartesian theatre and suggests that as a notion it should be abandoned. | https://en.wikipedia.org/wiki/Bridge_locus |
In neuroscience, "uncertainty aversion" and "uncertainty tolerance" in semantic representations appear to correlate with the terms "splitters" and "lumpers" respectively. As neuroscientist Marc-Lluís Vives observes:"Our survival is possible because every day we make use of previously acquired categories to navigate the world. Every single mug we encounter is distinct, but fundamentally the same. Thanks to this powerful capacity to classify distinct stimuli under the same category, we can generalize our knowledge from the previously encountered subset of mugs to a future subset of mugs. | https://en.wikipedia.org/wiki/Lumpers_and_splitters |
However, this also posits a dilemma: Is a glass mug still a mug? That is, what are the defining principles that make something a "mug"? Establishing this is fundamental since it also affects its relationship with its close-neighbors. Conceptualizing a mug as very different from a glass creates a more clear-cut mapping between the input—that is, the stimulus perceived—and the output that a person needs to generate—that is, the response, such as drinking coffee. Classical work in cognitive science demonstrates that the more similar two stimuli are, the harder it is to discriminate them and respond with different behavior." | https://en.wikipedia.org/wiki/Lumpers_and_splitters |
In neuroscience, Dale's principle (or Dale's law) is a rule attributed to the English neuroscientist Henry Hallett Dale. The principle basically states that a neuron performs the same chemical action at all of its synaptic connections to other cells, regardless of the identity of the target cell. However, there has been disagreement about the precise wording. Because of an ambiguity in the original statement, there are actually two versions of the principle, one that has been shown definitively to be false, and another that remains a valuable rule of thumb. | https://en.wikipedia.org/wiki/Dale's_principle |
The term "Dale's principle" was first used by Sir John Eccles in 1954, in a passage reading, "In conformity with Dale's principle (1934, 1952) that the same chemical transmitter is released from all the synaptic terminals of a neurone…" Some modern writers have understood the principle to state that neurons release one and only one transmitter at all of their synapses, which is false. Others, including Eccles himself in later publications, have taken it to mean that neurons release the same set of transmitters at all of their synapses. Dale himself never stated his "principle" in an explicit form. | https://en.wikipedia.org/wiki/Dale's_principle |
The source that Eccles referred to was a lecture published by Dale in 1934, called Pharmacology and nerve endings, describing some of the early research into the physiology of neurotransmission. At that time, only two chemical transmitters were known, acetylcholine and noradrenaline (then thought to be adrenaline). In the peripheral nervous system, cholinergic and adrenergic transmission were known to arise from different groups of nerve fibers. | https://en.wikipedia.org/wiki/Dale's_principle |
Dale was interested in the possibility that a neuron releasing one of these chemicals in the periphery might also release the same chemical at central synapses. He wrote: It is to be noted, further, that in the cases for which direct evidence is already available, the phenomena of regeneration appear to indicate that the nature of the chemical function, whether cholinergic or adrenergic, is characteristic for each particular neurone, and unchangeable. And near the end of the paper: When we are dealing with two different endings of the same sensory neurone, the one peripheral and concerned with vasodilatation and the other at a central synapse, can we suppose that the discovery and identification of a chemical transmitter of axon-reflex vasodilatation would furnish a hint as to the nature of the transmission process at a central synapse? | https://en.wikipedia.org/wiki/Dale's_principle |
The possibility has at least some value as a stimulus to further experiment. With only two transmitter chemicals known to exist at the time, the possibility of a neuron releasing more than one transmitter at a single synapse did not enter anybody's mind, and so no care was taken to frame hypotheses in a way that took this possibility into account. The resulting ambiguity in the initial statements led to some confusion in the literature about the precise meaning of the principle. | https://en.wikipedia.org/wiki/Dale's_principle |
Nicoll and Malenka, for example, understood it to state that a neuron always releases one and only one neurotransmitter at all of its synapses. In this form it is certainly false. | https://en.wikipedia.org/wiki/Dale's_principle |
Many neurons release more than one neurotransmitter, in what is called "cotransmission". Although there were earlier hints, the first formal proposal of this discovery did not come until 1976. Most neurons release several different chemical messengers. | https://en.wikipedia.org/wiki/Dale's_principle |
In modern neuroscience, neurons are often classified by their neurotransmitter and most important cotransmitter, for example striatal GABA neurons utilize either opioid peptides or substance P as the primary cotransmitter. In a 1976 publication, however, Eccles interpreted the principle in a subtly different way: "I proposed that Dale’s Principle be defined as stating that at all the axonal branches of a neurone, there was liberation of the same transmitter substance or substances." The addition of "or substances" is critical. | https://en.wikipedia.org/wiki/Dale's_principle |
With this change, the principle allows for the possibility of neurons releasing more than one transmitter, and only asserts that the same set are released at all synapses. In this form, it continues to be an important rule of thumb, with only a few known exceptions, including David Sulzer and Stephen Rayport's finding that dopamine neurons also release glutamate as a neurotransmitter, but at separate release sites. == References == | https://en.wikipedia.org/wiki/Dale's_principle |
In neuroscience, Golgi cells are inhibitory interneurons found within the granular layer of the cerebellum. They were first identified as inhibitory in 1964. It was also the first example of an inhibitory feedback network, where the inhibitory interneuron was identified anatomically. | https://en.wikipedia.org/wiki/Golgi_cells |
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. | https://en.wikipedia.org/wiki/Golgi_cells |
The main synapse made by these cells is a synapse onto the mossy fibre - granule cell excitatory synapse in a glomerulus. The glomerulus is made up of the mossy fibre terminal, granule cell dendrites, the Golgi terminal and is enclosed by a glial coat. The Golgi cell acts by altering the mossy fibre - granule cell synapse. | https://en.wikipedia.org/wiki/Golgi_cells |
The Golgi cells use GABA as their neurotransmitter. The basal level of GABA produces a postsynaptic leak conductance by tonically activating alpha 6-containing GABA-A receptors on the granule cell. These high-affinity receptors are located both synaptically and extrasynaptically on the granule cell. | https://en.wikipedia.org/wiki/Golgi_cells |
The synaptic receptors mediate phasic contraction, duration of around 20-30ms whereas the extrasynapatic receptors mediate tonic inhibition of around 200ms, and are activated by synapse spill over.Additionally the GABA acts on GABA-B receptors which are located presynaptically on the mossy fibre terminal. These inhibit the mossy fibre evoked EPSCs of the granule cell in a temperature and frequency dependent manner. At high mossy firing frequency (10 Hz) there is no effect of GABA acting on presynaptic GABA-B receptors on evoked EPSCs. However, at low (1 Hz) firing the GABA does have an effect on the EPSCs mediated via these presynaptic GABA-B receptors. | https://en.wikipedia.org/wiki/Golgi_cells |
In neuroscience, a frequency-current curve (fI or F-I curve) is the function that relates the net synaptic current (I) flowing into a neuron to its firing rate (F) Because the f-I curve only specifies the firing rate rather than exact spike times, it is a concept suited to the rate coding rather than temporal coding model of neuronal computation. Common mathematical models for f-I include the sigmoid, exponential, and rectified linear functions. The experimental study of how neuronal firing rates can relate to applied currents goes back at least as far as Hodgkin. == References == | https://en.wikipedia.org/wiki/F-I_curve |
In neuroscience, a neurometric function is a mathematical formula relating the activity of brain cells to aspects of an animal's sensory experience or motor behavior. Neurometric functions provide a quantitative summary of the neural code of a particular brain region. In sensory neuroscience, neurometric functions measure the probability with which a sensory stimulus would be perceived based on decoding the activity of a given neuron or collection of neurons. The concept was introduced to investigate the visibility of visual stimuli, by applying Detection theory to the output of single neurons of visual cortex.Comparing neurometric functions to psychometric functions (by recording from neurons in the brain of the observer) can reveal whether the neural representation in the recorded region constrains perceptual accuracy.In motor neuroscience, neurometric functions are used to predict body movements from the activity of neuronal populations in regions such as motor cortex. Such neurometric functions are used in the design of brain–computer interfaces. | https://en.wikipedia.org/wiki/Neurometric_function |
In neuroscience, a population vector is the sum of the preferred directions of a population of neurons, weighted by the respective spike counts. The formula for computing the (normalized) population vector, F {\displaystyle F} , takes the following form: F = ∑ j m j F j ∑ j m j {\displaystyle F={\frac {\sum _{j}m_{j}F_{j}}{\sum _{j}m_{j}}}} Where m j {\displaystyle m_{j}} is the activity of cell j {\displaystyle j} , and F j {\displaystyle F_{j}} is the preferred input for cell j {\displaystyle j} . Note that the vector F {\displaystyle F} encodes the input direction, F j {\displaystyle F_{j}} , in terms of the activation of a population of neurons. | https://en.wikipedia.org/wiki/Population_vector |
In neuroscience, a sensory map in the brain which has overlapping stimulus coding (e.g. location and quality) is called an orthogonal map. | https://en.wikipedia.org/wiki/Orthogonal_(computing) |
In neuroscience, a silent synapse is an excitatory glutamatergic synapse whose postsynaptic membrane contains NMDA-type glutamate receptors but no AMPA-type glutamate receptors. These synapses are named "silent" because normal AMPA receptor-mediated signaling is not present, rendering the synapse inactive under typical conditions. Silent synapses are typically considered to be immature glutamatergic synapses. As the brain matures, the relative number of silent synapses decreases. However, recent research on hippocampal silent synapses shows that while they may indeed be a developmental landmark in the formation of a synapse, that synapses can be "silenced" by activity, even once they have acquired AMPA receptors. Thus, silence may be a state that synapses can visit many times during their lifetimes. | https://en.wikipedia.org/wiki/Silent_synapse |
In neuroscience, an F wave is one of several motor responses which may follow the direct motor response (M) evoked by electrical stimulation of peripheral motor or mixed (sensory and motor) nerves. F-waves are the second of two late voltage changes observed after stimulation is applied to the skin surface above the distal region of a nerve, in addition to the H-reflex (Hoffman's Reflex) which is a muscle reaction in response to electrical stimulation of innervating sensory fibers. Traversal of F-waves along the entire length of peripheral nerves between the spinal cord and muscle, allows for assessment of motor nerve conduction between distal stimulation sites in the arm and leg, and related motoneurons (MN's) in the cervical and lumbosacral cord. F-waves are able to assess both afferent and efferent loops of the alpha motor neuron in its entirety. | https://en.wikipedia.org/wiki/F_wave |
As such, various properties of F-wave motor nerve conduction are analyzed in nerve conduction studies (NCS), and often used to assess polyneuropathies, resulting from states of neuronal demyelination and loss of peripheral axonal integrity.With respect to its nomenclature, the F-wave is so named as it was initially studied in the smaller muscles of the foot. The observation of F-waves in the same motor units (MU) as those present in the direct motor response (M), along with the presence of F-waves in deafferented animal and human models, indicates that F-waves require direct activation of motor axons to be elicited, and do not involve conduction along afferent sensory nerves. Thus, the F-wave is considered a wave, as opposed to a reflex. | https://en.wikipedia.org/wiki/F_wave |
In neuroscience, an excitatory postsynaptic potential (EPSP) is a postsynaptic potential that makes the postsynaptic neuron more likely to fire an action potential. This temporary depolarization of postsynaptic membrane potential, caused by the flow of positively charged ions into the postsynaptic cell, is a result of opening ligand-gated ion channels. These are the opposite of inhibitory postsynaptic potentials (IPSPs), which usually result from the flow of negative ions into the cell or positive ions out of the cell. EPSPs can also result from a decrease in outgoing positive charges, while IPSPs are sometimes caused by an increase in positive charge outflow. | https://en.wikipedia.org/wiki/Excitatory_postsynaptic_potential |
The flow of ions that causes an EPSP is an excitatory postsynaptic current (EPSC). EPSPs, like IPSPs, are graded (i.e. they have an additive effect). When multiple EPSPs occur on a single patch of postsynaptic membrane, their combined effect is the sum of the individual EPSPs. | https://en.wikipedia.org/wiki/Excitatory_postsynaptic_potential |
Larger EPSPs result in greater membrane depolarization and thus increase the likelihood that the postsynaptic cell reaches the threshold for firing an action potential. EPSPs in living cells are caused chemically. When an active presynaptic cell releases neurotransmitters into the synapse, some of them bind to receptors on the postsynaptic cell. | https://en.wikipedia.org/wiki/Excitatory_postsynaptic_potential |
Many of these receptors contain an ion channel capable of passing positively charged ions either into or out of the cell (such receptors are called ionotropic receptors). At excitatory synapses, the ion channel typically allows sodium into the cell, generating an excitatory postsynaptic current. This depolarizing current causes an increase in membrane potential, the EPSP. | https://en.wikipedia.org/wiki/Excitatory_postsynaptic_potential |
In neuroscience, anterograde tracing is a research method that is used to trace axonal projections from their source (the cell body, or soma) to their point of termination (the synapse). A hallmark of anterograde tracing is the labeling of the presynaptic and the postsynaptic neuron(s). The crossing of the synaptic cleft is a vital difference between the anterograde tracers and the dye fillers used for morphological reconstruction. The complementary technique is retrograde tracing, which is used to trace neural connections from their termination to their source (i.e. synapse to cell body). | https://en.wikipedia.org/wiki/Anterograde_labeling_method |
Both the anterograde and retrograde tracing techniques are based on the visualization of the biological process of axonal transport. The anterograde and retrograde tracing techniques allow the detailed descriptions of neuronal projections from a single neuron or a defined population of neurons to their various targets throughout the nervous system. These techniques allow the "mapping" of connections between neurons in a particular structure (e.g. the eye) and the target neurons in the brain. Much of what is currently known about connectional neuroanatomy was discovered through the use of the anterograde and retrograde tracing techniques. | https://en.wikipedia.org/wiki/Anterograde_labeling_method |
In neuroscience, ball and chain inactivation is a model to explain the fast inactivation mechanism of voltage-gated ion channels. The process is also called hinged-lid inactivation or N-type inactivation. A voltage-gated ion channel can be in three states: open, closed, or inactivated. | https://en.wikipedia.org/wiki/Ball_and_chain_inactivation |
The inactivated state is mainly achieved through fast inactivation, by which a channel transitions rapidly from an open to an inactivated state. The model proposes that the inactivated state, which is stable and non-conducting, is caused by the physical blockage of the pore. The blockage is caused by a "ball" of amino acids connected to the main protein by a string of residues on the cytoplasmic side of the membrane. | https://en.wikipedia.org/wiki/Ball_and_chain_inactivation |
The ball enters the open channel and binds to the hydrophobic inner vestibule within the channel. This blockage causes inactivation of the channel by stopping the flow of ions. This phenomenon has mainly been studied in potassium channels and sodium channels. | https://en.wikipedia.org/wiki/Ball_and_chain_inactivation |
In neuroscience, functional specialization is a theory which suggests that different areas in the brain are specialized for different functions. | https://en.wikipedia.org/wiki/Functional_specialization_(brain) |
In neuroscience, homeostatic plasticity refers to the capacity of neurons to regulate their own excitability relative to network activity. The term homeostatic plasticity derives from two opposing concepts: 'homeostatic' (a product of the Greek words for 'same' and 'state' or 'condition') and plasticity (or 'change'), thus homeostatic plasticity means "staying the same through change". | https://en.wikipedia.org/wiki/Homeostatic_plasticity |
In neuroscience, long-term potentiation (LTP) is a persistent strengthening of synapses based on recent patterns of activity. These are patterns of synaptic activity that produce a long-lasting increase in signal transmission between two neurons. The opposite of LTP is long-term depression, which produces a long-lasting decrease in synaptic strength. | https://en.wikipedia.org/wiki/Long-term_potentiation |
It is one of several phenomena underlying synaptic plasticity, the ability of chemical synapses to change their strength. As memories are thought to be encoded by modification of synaptic strength, LTP is widely considered one of the major cellular mechanisms that underlies learning and memory.LTP was discovered in the rabbit hippocampus by Terje Lømo in 1966 and has remained a popular subject of research since. Many modern LTP studies seek to better understand its basic biology, while others aim to draw a causal link between LTP and behavioral learning. Still, others try to develop methods, pharmacologic or otherwise, of enhancing LTP to improve learning and memory. LTP is also a subject of clinical research, for example, in the areas of Alzheimer's disease and addiction medicine. | https://en.wikipedia.org/wiki/Long-term_potentiation |
In neuroscience, nerve conduction velocity (CV) is the speed at which an electrochemical impulse propagates down a neural pathway. Conduction velocities are affected by a wide array of factors, which include age, sex, and various medical conditions. Studies allow for better diagnoses of various neuropathies, especially demyelinating diseases as these conditions result in reduced or non-existent conduction velocities. CV is an important aspect of nerve conduction studies. | https://en.wikipedia.org/wiki/Nerve_conduction_velocity |
In neuroscience, neurons have an interconnected nature which makes it extremely hard to isolate intact single neurons. As snRNA-seq has emerged as an alternative method of assessing a cell's transcriptome through the isolation of single nuclei, it has been possible to conduct single-neuron studies from postmortem human brain tissue. snRNA-seq has also enabled the first single neuron analysis of immediate early gene expression (IEGs) associated with memory formation in the mouse hippocampus. In 2019, Dmitry et al used the method on cortical tissue from ASD patients to identify ASD-associated transcriptomic changes in specific cell types, which is the first cell-type-specific transcriptome assessment in brains affected by ASD.Outside of neuroscience, snRNA-seq has also been used in other research areas. | https://en.wikipedia.org/wiki/SnRNA-seq |
In 2019, Haojia et al compared both scRNA-seq and snRNA-seq in a genomic study around the kidney. They found snRNA-seq accomplishes an equivalent gene detection rate to that of scRNA-seq in adult kidney with several significant advantages (including compatibility with frozen samples, reduced dissociation bias and so on ). In 2019, Joshi et al used snRNA-seq in a human lung biology study in which they found snRNA-seq allowed unbiased identification of cell types from frozen healthy and fibrotic lung tissues. Adult mammalian heart tissue can be extremely hard to dissociate without damaging cells, which does not allow for easy sequencing of the tissue. However, in 2020, German scientists presented the first report of sequencing an adult mammalian heart by using snRNA-seq and were able to provide practical cell‐type distributions within the heart | https://en.wikipedia.org/wiki/SnRNA-seq |
In neuroscience, predictive coding (also known as predictive processing) is a theory of brain function which postulates that the brain is constantly generating and updating a "mental model" of the environment. According to the theory, such a mental model is used to predict input signals from the senses that are then compared with the actual input signals from those senses. With the rising popularity of representation learning, the theory is being actively pursued and applied in machine learning and related fields.The phrase 'predictive coding' is also used in several other disciplines such as signal-processing technologies and law in loosely-related or unrelated senses. | https://en.wikipedia.org/wiki/Predictive_coding |
In neuroscience, quantum brain dynamics (QBD) is a hypothesis to explain the function of the brain within the framework of quantum field theory.As described by Harald Atmanspacher, "Since quantum theory is the most fundamental theory of matter that is currently available, it is a legitimate question to ask whether quantum theory can help us to understand consciousness." The original motivation in the early 20th century for relating quantum theory to consciousness was essentially philosophical. It is fairly plausible that conscious free decisions (“free will”) are problematic in a perfectly deterministic world, so quantum randomness might indeed open up novel possibilities for free will. | https://en.wikipedia.org/wiki/Quantum_consciousness |
(On the other hand, randomness is problematic for goal-directed volition!) Ricciardi and Umezawa proposed in 1967 a general theory of quanta of long-range coherent waves within and between brain cells, and showed a possible mechanism of memory storage and retrieval in terms of Nambu–Goldstone bosons. This was later fleshed out into a theory encompassing all biological cells and systems in the quantum biodynamics of Del Giudice and co-authors. | https://en.wikipedia.org/wiki/Quantum_consciousness |
Mari Jibu and Kunio Yasue later popularized these results and discussed the implications towards consciousness.Umezawa emphasizes that macroscopic and microscopic ordered states are both of quantum origin according to quantum field theory and points out the shortcomings of classical neuronal models in describing them. In 1981, theoretical exploration of the Ising model in Cayley tree topologies and large neural networks yielded an exact solution on closed trees with arbitrary branching ratios greater than two, exhibiting an unusual phase transition in local-apex and long-range site-site correlations. This finding directly raises the possibility of multiple cooperative modes being present in ordering states long-range within neural networks and their constituents, with Barth cooperative effects of the closed tree Ising model (structurally and connectivity dependent, with critical point a function of branching ratio and site-to-site energies of interaction) and Umezawa ordering of states (less structure dependent and with significantly greater degrees of freedom) independently or collectively guiding overall long-range macroscopic ordering often associated with higher cognitive functions in QBD. | https://en.wikipedia.org/wiki/Quantum_consciousness |
In neuroscience, repolarization refers to the change in membrane potential that returns it to a negative value just after the depolarization phase of an action potential which has changed the membrane potential to a positive value. The repolarization phase usually returns the membrane potential back to the resting membrane potential. The efflux of potassium (K+) ions results in the falling phase of an action potential. The ions pass through the selectivity filter of the K+ channel pore. | https://en.wikipedia.org/wiki/Repolarization |
Repolarization typically results from the movement of positively charged K+ ions out of the cell. The repolarization phase of an action potential initially results in hyperpolarization, attainment of a membrane potential, termed the afterhyperpolarization, that is more negative than the resting potential. Repolarization usually takes several milliseconds.Repolarization is a stage of an action potential in which the cell experiences a decrease of voltage due to the efflux of potassium (K+) ions along its electrochemical gradient. | https://en.wikipedia.org/wiki/Repolarization |
This phase occurs after the cell reaches its highest voltage from depolarization. After repolarization, the cell hyperpolarizes as it reaches resting membrane potential (−70 mV in neuron). | https://en.wikipedia.org/wiki/Repolarization |
Sodium (Na+) and potassium ions inside and outside the cell are moved by a sodium potassium pump, ensuring that electrochemical equilibrium remains unreached to allow the cell to maintain a state of resting membrane potential. In the graph of an action potential, the hyper-polarization section looks like a downward dip that goes lower than the line of resting membrane potential. | https://en.wikipedia.org/wiki/Repolarization |
In this afterhyperpolarization (the downward dip), the cell sits at more negative potential than rest (about −80 mV) due to the slow inactivation of voltage gated K+ delayed rectifier channels, which are the primary K+ channels associated with repolarization. At these low voltages, all of the voltage gated K+ channels close, and the cell returns to resting potential within a few milliseconds. A cell which is experiencing repolarization is said to be in its absolute refractory period. Other voltage gated K+ channels which contribute to repolarization include A-type channels and Ca2+-activated K+ channels. Protein transport molecules are responsible for Na+ out of the cell and K+ into the cell to restore the original resting ion concentrations. | https://en.wikipedia.org/wiki/Repolarization |
In neuroscience, saltatory conduction (from Latin saltus 'leap, jump') is the propagation of action potentials along myelinated axons from one node of Ranvier to the next node, increasing the conduction velocity of action potentials. The uninsulated nodes of Ranvier are the only places along the axon where ions are exchanged across the axon membrane, regenerating the action potential between regions of the axon that are insulated by myelin, unlike electrical conduction in a simple circuit. | https://en.wikipedia.org/wiki/Saltatory_conduction |
In neuroscience, single-unit recordings (also, single-neuron recordings) provide a method of measuring the electro-physiological responses of a single neuron using a microelectrode system. When a neuron generates an action potential, the signal propagates down the neuron as a current which flows in and out of the cell through excitable membrane regions in the soma and axon. A microelectrode is inserted into the brain, where it can record the rate of change in voltage with respect to time. These microelectrodes must be fine-tipped, impedance matching; they are primarily glass micro-pipettes, metal microelectrodes made of platinum, tungsten, iridium or even iridium oxide. | https://en.wikipedia.org/wiki/Single-neuron_activity |
Microelectrodes can be carefully placed close to the cell membrane, allowing the ability to record extracellularly. Single-unit recordings are widely used in cognitive science, where it permits the analysis of human cognition and cortical mapping. This information can then be applied to brain–machine interface (BMI) technologies for brain control of external devices. | https://en.wikipedia.org/wiki/Single-neuron_activity |
In neuroscience, synaptic plasticity is the ability of synapses to strengthen or weaken over time, in response to increases or decreases in their activity. Since memories are postulated to be represented by vastly interconnected neural circuits in the brain, synaptic plasticity is one of the important neurochemical foundations of learning and memory (see Hebbian theory). Plastic change often results from the alteration of the number of neurotransmitter receptors located on a synapse. There are several underlying mechanisms that cooperate to achieve synaptic plasticity, including changes in the quantity of neurotransmitters released into a synapse and changes in how effectively cells respond to those neurotransmitters. Synaptic plasticity in both excitatory and inhibitory synapses has been found to be dependent upon postsynaptic calcium release. | https://en.wikipedia.org/wiki/Synaptic_plasticity |
In neuroscience, the N100 or N1 is a large, negative-going evoked potential measured by electroencephalography (its equivalent in magnetoencephalography is the M100); it peaks in adults between 80 and 120 milliseconds after the onset of a stimulus, and is distributed mostly over the fronto-central region of the scalp. It is elicited by any unpredictable stimulus in the absence of task demands. It is often referred to with the following P200 evoked potential as the "N100-P200" or "N1-P2" complex. While most research focuses on auditory stimuli, the N100 also occurs for visual (see visual N1, including an illustration), olfactory, heat, pain, balance, respiration blocking, and somatosensory stimuli.The auditory N100 is generated by a network of neural populations in the primary and association auditory cortices in the superior temporal gyrus in Heschl's gyrus and planum temporale. | https://en.wikipedia.org/wiki/N100 |
It also could be generated in the frontal and motor areas. The area generating it is larger in the right hemisphere than the left.The N100 is preattentive and involved in perception because its amplitude is strongly dependent upon such things as the rise time of the onset of a sound, its loudness, interstimulus interval with other sounds, and the comparative frequency of a sound as its amplitude increases in proportion to how much a sound differs in frequency from a preceding one. | https://en.wikipedia.org/wiki/N100 |
Neuromagnetic research has linked it further to perception by finding that the auditory cortex has a tonotopic organization to N100. However, it also shows a link to a person's arousal and selective attention. N100 is decreased when a person controls the creation of auditory stimuli, such as their own voice. | https://en.wikipedia.org/wiki/N100 |
In neuroscience, the critical brain hypothesis states that certain biological neuronal networks work near phase transitions. Experimental recordings from large groups of neurons have shown bursts of activity, so-called neuronal avalanches, with sizes that follow a power law distribution. These results, and subsequent replication on a number of settings, led to the hypothesis that the collective dynamics of large neuronal networks in the brain operates close to the critical point of a phase transition. According to this hypothesis, the activity of the brain would be continuously transitioning between two phases, one in which activity will rapidly reduce and die, and another where activity will build up and amplify over time. In criticality, the brain capacity for information processing is enhanced, so subcritical, critical and slightly supercritical branching process of thoughts could describe how human and animal minds function. | https://en.wikipedia.org/wiki/Critical_brain_hypothesis |
In neuroscience, the default mode network (DMN), also known as the default network, default state network, or anatomically the medial frontoparietal network (M-FPN), is a large-scale brain network primarily composed of the dorsal medial prefrontal cortex, posterior cingulate cortex, precuneus and angular gyrus. It is best known for being active when a person is not focused on the outside world and the brain is at wakeful rest, such as during daydreaming and mind-wandering. It can also be active during detailed thoughts related to external task performance. | https://en.wikipedia.org/wiki/Default_network |
Other times that the DMN is active include when the individual is thinking about others, thinking about themselves, remembering the past, and planning for the future.The DMN was originally noticed to be deactivated in certain goal-oriented tasks and was sometimes referred to as the task-negative network, in contrast with the task-positive network. This nomenclature is now widely considered misleading, because the network can be active in internal goal-oriented and conceptual cognitive tasks. The DMN has been shown to be negatively correlated with other networks in the brain such as attention networks.Evidence has pointed to disruptions in the DMN of people with Alzheimer's disease and autism spectrum disorder. | https://en.wikipedia.org/wiki/Default_network |
In neuroscience, the hippocampus appears to be involved in SLAM-like computations, giving rise to place cells, and has formed the basis for bio-inspired SLAM systems such as RatSLAM. | https://en.wikipedia.org/wiki/Simultaneous_localization_and_mapping |
In neuroscience, the lateralized readiness potential (LRP) is an event-related brain potential, or increase in electrical activity at the surface of the brain, that is thought to reflect the preparation of motor activity on a certain side of the body; in other words, it is a spike in the electrical activity of the brain that happens when a person gets ready to move one arm, leg, or foot. It is a special form of bereitschaftspotential (a general pre-motor potential). LRPs are recorded using electroencephalography (EEG) and have numerous applications in cognitive neuroscience. | https://en.wikipedia.org/wiki/Lateralized_readiness_potential |
In neuroscience, the mass action principle suggests that the proportion of the brain that is injured is directly proportional to the decreased ability of memory functions. In other words, memory cannot be localized to a single cortical area, but is instead distributed throughout the cortex. This theory is contrasted by functional specialization. This is one of two principles that Karl Lashley published in 1950, alongside the equipotentiality principle. | https://en.wikipedia.org/wiki/Mass_Action_Principle_(neuroscience) |
In neuroscience, the reward system is a collection of brain structures and neural pathways that are responsible for reward-related cognition, including associative learning (primarily classical conditioning and operant reinforcement), incentive salience (i.e., motivation and "wanting", desire, or craving for a reward), and positively-valenced emotions, particularly emotions that involve pleasure (i.e., hedonic "liking").Terms that are commonly used to describe behavior related to the "wanting" or desire component of reward include appetitive behavior, approach behavior, preparatory behavior, instrumental behavior, anticipatory behavior, and seeking. Terms that are commonly used to describe behavior related to the "liking" or pleasure component of reward include consummatory behavior and taking behavior.The three primary functions of rewards are their capacity to: produce associative learning (i.e., classical conditioning and operant reinforcement); affect decision-making and induce approach behavior (via the assignment of motivational salience to rewarding stimuli); elicit positively-valenced emotions, particularly pleasure. | https://en.wikipedia.org/wiki/Reward_system |
In neuroscience, the visual P200 or P2 is a waveform component or feature of the event-related potential (ERP) measured at the human scalp. Like other potential changes measurable from the scalp, this effect is believed to reflect the post-synaptic activity of a specific neural process. The P2 component, also known as the P200, is so named because it is a positive going electrical potential that peaks at about 200 milliseconds (varying between about 150 and 275 ms) after the onset of some external stimulus. | https://en.wikipedia.org/wiki/P200 |
This component is often distributed around the centro-frontal and the parieto-occipital areas of the scalp. It is generally found to be maximal around the vertex (frontal region) of the scalp, however there have been some topographical differences noted in ERP studies of the P2 in different experimental conditions. Research on the visual P2 is at an early stage compared to other more established ERP components and there is much that we still do not know about it. | https://en.wikipedia.org/wiki/P200 |
Part of the difficulty of clearly characterizing this component is that it appears to be modulated by a large and diverse number of cognitive tasks. Functionally, there seems to be partial agreement amongst researchers in the field of cognitive neuroscience that the P2 represents some aspect of higher-order perceptual processing, modulated by attention. It is known that the P2 is typically elicited as part of the normal response to visual stimuli and has been studied in relation to visual search and attention, language context information, and memory and repetition effects. The amplitude of the peak of the waveform may be modulated by many different aspects of visual stimuli, which allow it to be used for studies of visual cognition and disease. In general, the P2 may be a part of cognitive matching system that compares sensory inputs with stored memory. | https://en.wikipedia.org/wiki/P200 |
In neuroscience, tractography is a 3D modeling technique used to visually represent nerve tracts using data collected by diffusion MRI. It uses special techniques of magnetic resonance imaging (MRI) and computer-based diffusion MRI. The results are presented in two- and three-dimensional images called tractograms.In addition to the long tracts that connect the brain to the rest of the body, there are complicated neural circuits formed by short connections among different cortical and subcortical regions. | https://en.wikipedia.org/wiki/Tractography |
The existence of these tracts and circuits has been revealed by histochemistry and biological techniques on post-mortem specimens. Nerve tracts are not identifiable by direct exam, CT, or MRI scans. This difficulty explains the paucity of their description in neuroanatomy atlases and the poor understanding of their functions. The most advanced tractography algorithm can produce 90% of the ground truth bundles, but it still contains a substantial amount of invalid results. | https://en.wikipedia.org/wiki/Tractography |
In neuroscience, visual cortical simple cells were first shown by David Hubel and Torsten Wiesel to have response properties that resemble Gabor filters, which are band-pass.In astronomy, band-pass filters are used to allow only a single portion of the light spectrum into an instrument. Band-pass filters can help with finding where stars lie on the main sequence, identifying redshifts, and many other applications. | https://en.wikipedia.org/wiki/Band-pass_filter |
In neurosurgery, excimer laser assisted non-occlusive anastomosis (ELANA) is a technique use to create a bypass without interrupting the blood supply in the recipient blood vessels. This reduces the risk of stroke or a rupture of an aneurysm. | https://en.wikipedia.org/wiki/Vascular_graft |
In neurourology, post-micturition convulsion syndrome (PMCS), also known informally as pee shivers, is the experience of shivering during or after urination. The syndrome appears to be more frequently experienced by males.The term "post-micturition convulsion syndrome" was coined in 1994 in the online question-and-answer newspaper column The Straight Dope, when a reader enquired about the phenomenon. | https://en.wikipedia.org/wiki/Post_micturition_convulsion_syndrome |
In neutral atoms, the approximate order in which subshells are filled is given by the n + l rule, also known as the: Madelung rule (after Erwin Madelung) Janet rule (after Charles Janet) Klechkowsky rule (after Vsevolod Klechkovsky) Wiswesser's rule (after William Wiswesser) aufbau rule or diagonal ruleHere n represents the principal quantum number and l the azimuthal quantum number; the values l = 0, 1, 2, 3 correspond to the s, p, d, and f subshells, respectively. The subshell ordering by this rule is 1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, 5s, 4d, 5p, 6s, 4f, 5d, 6p, 7s, 5f, 6d, 7p, 8s, 5g, ... For example, thallium (Z = 81) has the ground-state configuration 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p6 6s2 4f14 5d10 6p1 or in condensed form, 6s2 4f14 5d10 6p1. Other authors write the subshells outside of the noble gas core in order of increasing n, or if equal, increasing n + l, such as Tl (Z = 81) 4f14 5d10 6s2 6p1. They do so to emphasize that if this atom is ionized, electrons leave approximately in the order 6p, 6s, 5d, 4f, etc. On a related note, writing configurations in this way emphasizes the outermost electrons and their involvement in chemical bonding. | https://en.wikipedia.org/wiki/Madelung_rule |
Subshells with a lower n + l value are filled before those with higher n + l values. In the case of equal n + l values, the subshell with a lower n value is filled first. In general, subshells with the same n + l value have similar energies, but the s-orbitals (with l = 0) are exceptional: their energy levels are appreciably far from those of their n + l group and are closer to those of the next n + l group. | https://en.wikipedia.org/wiki/Madelung_rule |
This is why the periodic table is usually drawn to begin with the s-block elements.The Madelung energy ordering rule applies only to neutral atoms in their ground state. There are twenty elements (eleven in the d-block and nine in the f-block) for which the Madelung rule predicts an electron configuration that differs from that determined experimentally, although the Madelung-predicted electron configurations are at least close to the ground state even in those cases. One inorganic chemistry textbook describes the Madelung rule as essentially an approximate empirical rule although with some theoretical justification, based on the Thomas–Fermi model of the atom as a many-electron quantum-mechanical system. | https://en.wikipedia.org/wiki/Madelung_rule |
In neutral current interactions, a quark or a lepton (e.g., an electron or a muon) emits or absorbs a neutral Z boson. For example: e − → e − + Z 0 {\displaystyle \mathrm {e} ^{-}\to \mathrm {e} ^{-}+\mathrm {Z} ^{0}} Like the W± bosons, the Z0 boson also decays rapidly, for example: Z 0 → b + b ¯ {\displaystyle \mathrm {Z} ^{0}\to \mathrm {b} +{\bar {\mathrm {b} }}} Unlike the charged-current interaction, whose selection rules are strictly limited by chirality, electric charge, and / or weak isospin, the neutral-current Z0 interaction can cause any two fermions in the standard model to deflect: Either particles or anti-particles, with any electric charge, and both left- and right-chirality, although the strength of the interaction differs.The quantum number weak charge (QW) serves the same role in the neutral current interaction with the Z0 that electric charge (Q, with no subscript) does in the electromagnetic interaction: It quantifies the vector part of the interaction. Its value is given by: Q w = 2 T 3 − 4 Q sin 2 θ w = 2 T 3 − Q + ( 1 − 4 sin 2 θ w ) Q . {\displaystyle Q_{\mathsf {w}}=2\,T_{3}-4\,Q\,\sin ^{2}\theta _{\mathsf {w}}=2\,T_{3}-Q+(1-4\,\sin ^{2}\theta _{\mathsf {w}})\,Q~.} | https://en.wikipedia.org/wiki/Weak_nuclear_interaction |
Since the weak mixing angle θ w ≈ 29 ∘ , {\displaystyle \ \theta _{\mathsf {w}}\approx 29^{\circ }\ ,} the parenthetic expression ( 1 − 4 sin 2 θ w ) ≈ 0.060 , {\displaystyle \ (1-4\,\sin ^{2}\theta _{\mathsf {w}})\approx 0.060\ ,} with its value varying slightly with the momentum difference (called “running”) between the particles involved. Hence Q w ≈ 2 T 3 − Q = sgn ( Q ) ( 1 − | Q | ) , {\displaystyle \ Q_{\mathsf {w}}\approx 2\ T_{3}-Q=\operatorname {sgn}(Q)\ {\big (}1-|Q|{\big )}\ ,} since by convention sgn T 3 ≡ sgn Q , {\displaystyle \ \operatorname {sgn} T_{3}\equiv \operatorname {sgn} Q\ ,} and for all fermions involved in the weak interaction T 3 = ± 1 2 . {\displaystyle \ T_{3}=\pm {\tfrac {1}{2}}~.} The weak charge of charged leptons is then close to zero, so these mostly interact with the Z boson through the axial coupling. | https://en.wikipedia.org/wiki/Weak_nuclear_interaction |
In neutral or absolute geometry, and in hyperbolic geometry, there may be many lines parallel to a given line l {\displaystyle l} through a point P {\displaystyle P} not on line R {\displaystyle R} ; however, in the plane, two parallels may be closer to l {\displaystyle l} than all others (one in each direction of R {\displaystyle R} ). Thus it is useful to make a new definition concerning parallels in neutral geometry. If there are closest parallels to a given line they are known as the limiting parallel, asymptotic parallel or horoparallel (horo from Greek: ὅριον — border). For rays, the relation of limiting parallel is an equivalence relation, which includes the equivalence relation of being coterminal. If, in a hyperbolic triangle, the pairs of sides are limiting parallel, then the triangle is an ideal triangle. | https://en.wikipedia.org/wiki/Limiting_parallel |
In neutral prosody, Turkish verb phrases are primarily head-final, as the verb comes after its complement. Variation in object-verb ordering is not strictly rigid. However, constructions where the verb precedes the object are less common. ] | https://en.wikipedia.org/wiki/Head-directionality_parameter |
In neutron activation, the probe is prepared directly from the sample material by converting very small part of one of the elements of the sample material into the desired PAC probe or its parent isotope by neutron capture. As with implantation, radiation damage must be healed. This method is limited to sample materials containing elements from which neutron capture PAC probes can be made. Furthermore, samples can be intentionally contaminated with those elements that are to be activated. For example, hafnium is excellently suited for activation because of its large capture cross section for neutrons. | https://en.wikipedia.org/wiki/Perturbed_angular_correlation |
In neutron stars, neutron heavy nuclei are found as relativistic electrons penetrate the nuclei and produce inverse beta decay, wherein the electron combines with a proton in the nucleus to make a neutron and an electron-neutrino: As more and more neutrons are created in nuclei the energy levels for neutrons get filled up to an energy level equal to the rest mass of a neutron. At this point any electron penetrating a nucleus will create a neutron, which will "drip" out of the nucleus. At this point we have: E F n = m n c 2 {\displaystyle E_{\text{F}}^{n}=m_{n}c^{2}\,} And from this point onwards the equation E F n = ( p F n ) 2 c 2 + m n 2 c 4 {\displaystyle E_{\text{F}}^{n}={\sqrt {\left(p_{\text{F}}^{n}\right)^{2}c^{2}+m_{n}^{2}c^{4}}}\,} applies, where pFn is the Fermi momentum of the neutron. As we go deeper into the neutron star the free neutron density increases, and as the Fermi momentum increases with increasing density, the Fermi energy increases, so that energy levels lower than the top level reach neutron drip and more and more neutrons drip out of nuclei so that we get nuclei in a neutron fluid. Eventually all the neutrons drip out of nuclei and we have reached the neutron fluid interior of the neutron star. | https://en.wikipedia.org/wiki/Proton_drip_line |
In neutron time-of-flight scattering, a form of inelastic neutron scattering, the initial position and velocity of a pulse of neutrons is fixed, and their final position and the time after the pulse that the neutrons are detected are measured. By the principle of conservation of momentum, these pairs of coordinates may be transformed into momenta and energies for the neutrons, and the experimentalist may use this information to calculate the momentum and energy transferred to the sample. Inverse geometry spectrometers are also possible. In this case, the final position and velocity are fixed, and the incident coordinates varied. Time-of-flight scattering can be performed at either a research reactor or a spallation source. | https://en.wikipedia.org/wiki/Neutron_time-of-flight_scattering |
In new construction, builders can either avoid clear cutting or clearing an entire property and disturbing other large flora or builders can completely clear an area of all flora to save construction time and replace the clearing with juvenile specimens once the job is complete. The downside to this is additional costs involved with purchasing replacements. The builder may also choose to plant additional native trees and other flora after construction to help the property blend with natural surroundings. In some planned developments, natural landscaping is the requirement. Builders may not remove trees larger than a specific diameter and owners may not arbitrarily cut trees without a permit. | https://en.wikipedia.org/wiki/Natural_landscaping |
In new construction, the extra insulation and wall framing cost may be offset by not requiring a dedicated central heating system. A central furnace is often justified or required to ensure sufficiently uniform temperatures in homes with numerous rooms, more than one floor, air conditioning, or large size. Small furnaces are not very expensive, and some ductwork to every room is generally required to provide ventilation air. When peak demand and annual energy use are low, costly and sophisticated central heating systems are only sometimes needed. | https://en.wikipedia.org/wiki/Superinsulation |
Hence, even electric resistance heaters may be used. Electric heaters are typically only used on cold winter nights when the overall demand for electricity in the rest of the house is low. Other backup heaters, such as wood pellets, wood stoves, natural gas boilers, or even furnaces, are widely used. | https://en.wikipedia.org/wiki/Superinsulation |
The cost of a superinsulation retrofit should be balanced against the future price of heating fuel (which can be expected to fluctuate from year to year due to supply problems, natural disasters, or geopolitical events), the desire to reduce pollution from heating a building, or the desire to provide exceptional thermal comfort. During a power failure, a superinsulated house stays warm longer as heat loss is much less than usual, but the thermal storage capacity of the structural materials and contents is the same. Adverse weather may hamper efforts to restore power, leading to weeks or more outages. When deprived of their continuous supply of electricity (either for heat directly or to operate gas-fired furnaces), conventional houses cool rapidly and may be at greater risk of costly damage from freezing water pipes. Residents who use supplemental heating methods without proper care during such episodes or at any other time may subject themselves to the risk of fire or carbon monoxide poisoning. | https://en.wikipedia.org/wiki/Superinsulation |
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