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BCM Theory
BCM theory, BCM synaptic modification, or the BCM rule, named for Elie Bienenstock, Leon Cooper, and Paul Munro, is a physical theory of learning in the visual cortex developed in 1981. The BCM model proposes a sliding threshold for long-term potentiation (LTP) or long-term depression (LTD) induction, and states that synaptic plasticity is stabilized by a dynamic adaptation of the time-averaged postsynaptic activity. According to the BCM model, when a pre-synaptic neuron fires, the post-synaptic neurons will tend to undergo LTP if it is in a high-activity state (e.g., is firing at high frequency, and/or has high internal calcium concentrations), or LTD if it is in a lower-activity state (e.g., firing in low frequency, low internal calcium concentrations). This theory is often used to explain how cortical neurons can undergo both LTP or LTD depending on different conditioning stimulus protocols applied to pre-synaptic neurons (usually high-frequency stimulation, or HFS, for LTP, or l ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Elie Bienenstock
Elie and Earlsferry is a coastal town and former royal burgh in Fife, and parish, Scotland, situated within the East Neuk beside Chapel Ness on the north coast of the Firth of Forth, eight miles east of Leven. The burgh comprised the linked villages of Elie ( ) to the east and to the west Earlsferry, which were formally merged in 1930 by the Local Government (Scotland) Act 1929. To the north is the village of Kilconquhar and Kilconquhar Loch. The civil parish has a population of 861 (in 2011).Census of Scotland 2011, Table KS101SC – Usually Resident Population, publ. by National Records of Scotland. Web site http://www.scotlandscensus.gov.uk/ retrieved March 2016. See "Standard Outputs", Table KS101SC, Area type: Civil Parish 1930 Ancient times Earlsferry, the older of the two villages, was first settled in time immemorial . It is said that MacDuff, the Earl of Fife, crossed the Forth here in 1054 while fleeing from King Macbeth. In particular the legend tells of his es ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Synaptic Plasticity
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. Historical discoveries In 1973, Terje Lømo and Tim Bliss first described the now widely studied phenomenon of long-term potent ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Biophysics
Biophysics is an interdisciplinary science that applies approaches and methods traditionally used in physics to study biological phenomena. Biophysics covers all scales of biological organization, from molecular to organismic and populations. Biophysical research shares significant overlap with biochemistry, molecular biology, physical chemistry, physiology, nanotechnology, bioengineering, computational biology, biomechanics, developmental biology and systems biology. The term ''biophysics'' was originally introduced by Karl Pearson in 1892. Roland Glaser. Biophysics: An Introduction'. Springer; 23 April 2012. . The term ''biophysics'' is also regularly used in academia to indicate the study of the physical quantities (e.g. electric current, temperature, stress, entropy) in biological systems. Other biological sciences also perform research on the biophysical properties of living organisms including molecular biology, cell biology, chemical biology, and biochemistry. Ove ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Parallel Distributed Processing
Connectionism refers to both an approach in the field of cognitive science that hopes to explain mental phenomena using artificial neural networks (ANN) and to a wide range of techniques and algorithms using ANNs in the context of artificial intelligence to build more intelligent machines. Connectionism presents a cognitive theory based on simultaneously occurring, distributed signal activity via connections that can be represented numerically, where learning occurs by modifying connection strengths based on experience. Some advantages of the connectionist approach include its applicability to a broad array of functions, structural approximation to biological neurons, low requirements for innate structure, and capacity for graceful degradation. Some disadvantages include the difficulty in deciphering how ANNs process information, or account for the compositionality of mental representations, and a resultant difficulty explaining phenomena at a higher level. The success of deep l ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Monocular Deprivation
Monocular deprivation is an experimental technique used by neuroscientists to study central nervous system plasticity. Generally, one of an animal's eyes is sutured shut during a period of high cortical plasticity (4–5 weeks-old in mice (Gordon 1997)). This manipulation serves as an animal model for amblyopia, a permanent deficit in visual sensation not due to abnormalities in the eye (which occurs, for example, in children who grow up with cataracts - even after cataract removal, they do not see as well as others). Background David Hubel and Torsten Wiesel (who won the Nobel prize in Physiology for their elucidation of receptive field properties of cells in primary visual cortex) first performed the technique in felines. Kittens, although less-closely related evolutionarily to humans even than rodents, have a remarkably similar visual system to humans. They found that ocular dominance columns (the orderly clustering of V1 neurons representing visual input from one or both ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nature (journal)
''Nature'' is a British weekly scientific journal founded and based in London, England. As a multidisciplinary publication, ''Nature'' features peer-reviewed research from a variety of academic disciplines, mainly in science and technology. It has core editorial offices across the United States, continental Europe, and Asia under the international scientific publishing company Springer Nature. ''Nature'' was one of the world's most cited scientific journals by the Science Edition of the 2019 '' Journal Citation Reports'' (with an ascribed impact factor of 42.778), making it one of the world's most-read and most prestigious academic journals. , it claimed an online readership of about three million unique readers per month. Founded in autumn 1869, ''Nature'' was first circulated by Norman Lockyer and Alexander Macmillan as a public forum for scientific innovations. The mid-20th century facilitated an editorial expansion for the journal; ''Nature'' redoubled its efforts in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Serena Dudek
Serena M. Dudek (born 1964; Anaheim, California), is an American neuroscientist known for her work on long-term depression and synaptic plasticity in the CA2 region of the hippocampus. Education Early years Dudek's father was an English professor and Fullerton College and her mother was a clinical cytologist and medical technologist. In High school, she worked at Knott's Berry Farm selling ice cream and popcorn. She was also on the drill team at Savanna High School. Undergraduate In 1982 Serena Dudek matriculated into the University of California, Irvine. Dudek worked as an undergraduate researcher in the lab of Gary Lynch studying the degradation of brain spectrin, also known as fodrin, by calpains. Graduate Serena Dudek enrolled a Ph.D. program at Brown University where she joined Mark Bear's lab to study long-term depression in a collaboration with Leon Cooper Leon N Cooper (born February 28, 1930) is an American physicist and Nobel Prize laureate who, with Joh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Long-term Depression
In neurophysiology, long-term depression (LTD) is an activity-dependent reduction in the efficacy of neuronal synapses lasting hours or longer following a long patterned stimulus. LTD occurs in many areas of the CNS with varying mechanisms depending upon brain region and developmental progress. As the opposing process to long-term potentiation (LTP), LTD is one of several processes that serves to selectively weaken specific synapses in order to make constructive use of synaptic strengthening caused by LTP. This is necessary because, if allowed to continue increasing in strength, synapses would ultimately reach a ceiling level of efficiency, which would inhibit the encoding of new information. Both LTD and LTP are forms of synaptic plasticity. Characterisation LTD in the hippocampus and cerebellum have been the best characterized, but there are other brain areas in which mechanisms of LTD are understood. LTD has also been found to occur in different types of neurons that rele ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Long-term Potentiation
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. 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 enhanc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Normalisable Wave Function
A wave function in quantum physics is a mathematical description of the quantum state of an isolated quantum system. The wave function is a complex-valued probability amplitude, and the probabilities for the possible results of measurements made on the system can be derived from it. The most common symbols for a wave function are the Greek letters and (lower-case and capital psi, respectively). The wave function is a function of the degrees of freedom corresponding to some maximal set of commuting observables. Once such a representation is chosen, the wave function can be derived from the quantum state. For a given system, the choice of which commuting degrees of freedom to use is not unique, and correspondingly the domain of the wave function is also not unique. For instance, it may be taken to be a function of all the position coordinates of the particles over position space, or the momenta of all the particles over momentum space; the two are related by a Fouri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Purkinje Cell
Purkinje cells, or Purkinje neurons, are a class of GABAergic inhibitory neurons located in the cerebellum. They are named after their discoverer, Czech anatomist Jan Evangelista Purkyně, who characterized the cells in 1839. Structure These cells are some of the largest neurons in the human brain ( Betz cells being the largest), with an intricately elaborate dendritic arbor, characterized by a large number of dendritic spines. Purkinje cells are found within the Purkinje layer in the cerebellum. Purkinje cells are aligned like dominos stacked one in front of the other. Their large dendritic arbors form nearly two-dimensional layers through which parallel fibers from the deeper-layers pass. These parallel fibers make relatively weaker excitatory (glutamatergic) synapses to spines in the Purkinje cell dendrite, whereas climbing fibers originating from the inferior olivary nucleus in the medulla provide very powerful excitatory input to the proximal dendrites and cell s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Leon Cooper
Leon N Cooper (born February 28, 1930) is an American physicist and Nobel Prize laureate who, with John Bardeen and John Robert Schrieffer, developed the BCS theory of superconductivity. His name is also associated with the Cooper pair and co-developer of the BCM theory of synaptic plasticity. Biography and career Cooper graduated from the Bronx High School of Science in 1947 and received a BA in 1951, MA in 1953, and PhD in 1954 from Columbia University. He spent a year at the Institute for Advanced Study and taught at the University of Illinois and Ohio State University before coming to Brown University in 1958. He has been the Thomas J. Watson Sr. Professor of Science at Brown since 1974, and Director of the Institute for Brain and Neural Systems which he founded in 1973. Along with colleague Charles Elbaum, he founded the tech company ''Nestor'', dedicated to finding commercial applications for artificial neural networks. Nestor, along with Intel, developed the Ni1000 neural ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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