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Fear Conditioning
Pavlovian fear conditioning is a behavioral paradigm in which organisms learn to predict aversive events. It is a form of learning in which an aversive stimulus (e.g. an electrical shock) is associated with a particular neutral context (e.g., a room) or neutral stimulus (e.g., a tone), resulting in the expression of fear responses to the originally neutral stimulus or context. This can be done by pairing the neutral stimulus with an aversive stimulus (e.g., an electric shock, loud noise, or unpleasant odor). Eventually, the neutral stimulus alone can elicit the state of fear. In the vocabulary of classical conditioning, the neutral stimulus or context is the "conditional stimulus" (CS), the aversive stimulus is the "unconditional stimulus" (US), and the fear is the "conditional response" (CR). Fear conditioning has been studied in numerous species, from snails to humans. In humans, conditioned fear is often measured with verbal report and galvanic skin response. In other animals ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Learning
Learning is the process of acquiring new understanding, knowledge, behaviors, skills, value (personal and cultural), values, Attitude (psychology), attitudes, and preferences. The ability to learn is possessed by humans, non-human animals, and some machine learning, machines; there is also evidence for some kind of learning in certain plants. Some learning is immediate, induced by a single event (e.g. being burned by a Heat, hot stove), but much skill and knowledge accumulate from repeated experiences. The changes induced by learning often last a lifetime, and it is hard to distinguish learned material that seems to be "lost" from that which cannot be retrieved. Human learning starts at birth (it might even start before) and continues until death as a consequence of ongoing interactions between people and their environment. The nature and processes involved in learning are studied in many established fields (including educational psychology, neuropsychology, experimental psycho ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hippocampus
The hippocampus (: hippocampi; via Latin from Ancient Greek, Greek , 'seahorse'), also hippocampus proper, is a major component of the brain of humans and many other vertebrates. In the human brain the hippocampus, the dentate gyrus, and the subiculum are components of the hippocampal formation located in the limbic system. The hippocampus plays important roles in the Memory consolidation, consolidation of information from short-term memory to long-term memory, and in spatial memory that enables Navigation#Navigation in spatial cognition, navigation. In humans, and other primates the hippocampus is located in the archicortex, one of the three regions of allocortex, in each cerebral hemisphere, hemisphere with direct neural projections to, and reciprocal indirect projections from the neocortex. The hippocampus, as the medial pallium, is a structure found in all vertebrates. In Alzheimer's disease (and other forms of dementia), the hippocampus is one of the first regions of th ... [...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 enhanci ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electrophysiology
Electrophysiology (from [see the Electron#Etymology, etymology of "electron"]; ; and ) is the branch of physiology that studies the electrical properties of biological cell (biology), cells and tissues. It involves measurements of voltage changes or electric current or manipulations on a wide variety of scales from single ion channel proteins to whole organs like the heart. In neuroscience, it includes measurements of the electrical activity of neurons, and, in particular, action potential activity. Recordings of large-scale electric signals from the nervous system, such as electroencephalography, may also be referred to as electrophysiological recordings. They are useful for electrodiagnostic medicine, electrodiagnosis and monitoring (medicine), monitoring. Definition and scope Classical electrophysiological techniques Principle and mechanisms Electrophysiology is the branch of physiology that pertains broadly to the flow of ions (ion current) in biological tissues and, in p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Amygdala
The amygdala (; : amygdalae or amygdalas; also '; Latin from Greek language, Greek, , ', 'almond', 'tonsil') is a paired nucleus (neuroanatomy), nuclear complex present in the Cerebral hemisphere, cerebral hemispheres of vertebrates. It is considered part of the limbic system. In Primate, primates, it is located lateral and medial, medially within the temporal lobes. It consists of many nuclei, each made up of further subnuclei. The subdivision most commonly made is into the Basolateral amygdala, basolateral, Central nucleus of the amygdala, central, cortical, and medial nuclei together with the intercalated cells of the amygdala, intercalated cell clusters. The amygdala has a primary role in the processing of memory, decision making, decision-making, and emotions, emotional responses (including fear, anxiety, and aggression). The amygdala was first identified and named by Karl Friedrich Burdach in 1822. Structure Thirteen Nucleus (neuroanatomy), nuclei have been identif ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
DNA Methyltransferase
In biochemistry, the DNA methyltransferase (DNA MTase, DNMT) family of enzymes catalyze the transfer of a methyl group to DNA. DNA methylation serves a wide variety of biological functions. All the known DNA methyltransferases use S-adenosyl methionine (SAM) as the methyl donor. Classification Substrate MTases can be divided into three different groups on the basis of the chemical reactions they catalyze: * m6A - those that generate N6-methyladenine * m4C - those that generate N4-methylcytosine * m5C - those that generate C5-methylcytosine m6A and m4C methyltransferases are found primarily in prokaryotes (although recent evidence has suggested that m6A is abundant in eukaryotes). m5C methyltransferases are found in some lower eukaryotes, in most higher plants, and in animals beginning with the echinoderms. The m6A methyltransferases (N-6 adenine-specific DNA methylase) (A-Mtase) are enzymes that specifically methylate the amino group at the C-6 position of adenine ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
DNA Demethylation
For molecular biology in mammals, DNA demethylation causes replacement of 5-methylcytosine (5mC) in a DNA sequence by cytosine (C) (see figure of 5mC and C). DNA demethylation can occur by an active process at the site of a 5mC in a DNA sequence or, in replicating cells, by preventing addition of methyl groups to DNA so that the replicated DNA will largely have cytosine in the DNA sequence (5mC will be diluted out). Methylated cytosine is frequently present in the linear DNA sequence where a cytosine is followed by a guanine in a Directionality (molecular biology), 5' → 3' direction (a CpG site). In mammals, DNA methyltransferases (which add methyl groups to DNA bases) exhibit a strong sequence preference for cytosines at CpG sites. There appear to be more than 20 million CpG dinucleotides in the human genome (see CpG site#Genomic distribution, genomic distribution). In mammals, on average, 70% to 80% of CpG cytosines are methylated, though the level of methylation varies with ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tet Methylcytosine Dioxygenase 1
Ten-eleven translocation methylcytosine dioxygenase 1 (TET1) is a member of the TET family of enzymes, in humans it is encoded by the TET1 gene. Its function, regulation, and utilizable pathways remain a matter of current research while it seems to be involved in DNA demethylation and therefore gene regulation, but is expressed as different isoforms which may have distinct functions. Discovery TET1 was first discovered in a 61-year-old patient with a rare variation of t(10;11)(q22;q23) acute myeloid leukemia (AML) as a zinc-finger binding protein (specifically on the CXXC domain) that fuses to the gene MLL. Another study confirmed that this protein was a translocation partner of MLL in an 8-year-old patient with t(10;11)(q22;q23) AML and named the protein Ten-Eleven Translocation 1. Function TET1 catalyzes the conversion of the modified DNA base 5-methylcytosine (5-mC) to 5-hydroxymethylcytosine (5-hmC). : TET1 produces 5-hmC by oxidation of 5-mC in an iron and al ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
DNA Methylation
DNA methylation is a biological process by which methyl groups are added to the DNA molecule. Methylation can change the activity of a DNA segment without changing the sequence. When located in a gene promoter (genetics), promoter, DNA methylation typically acts to repress gene Transcription (genetics), transcription. In mammals, DNA methylation is essential for normal development and is associated with a number of key processes including genomic imprinting, X-chromosome inactivation, repression of transposable elements, aging, and carcinogenesis. As of 2016, two nucleobases have been found on which natural, enzymatic DNA methylation takes place: adenine and cytosine. The modified bases are N6-methyladenine,D. B. Dunn, J. D. Smith: "The occurrence of 6-methylaminopurine in deoxyribonucleic acids". In: ''Biochem J.'' 68(4), Apr 1958, S. 627–636. [//www.ncbi.nlm.nih.gov/pubmed/13522672?dopt=Abstract PMID 13522672]. . 5-methylcytosineB. F. Vanyushin, S. G. Tkacheva, A. N. Belozers ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dnmt
In biochemistry, the DNA methyltransferase (DNA MTase, DNMT) family of enzymes catalyze the transfer of a methyl group to DNA. DNA methylation serves a wide variety of biological functions. All the known DNA methyltransferases use S-adenosyl methionine (SAM) as the methyl donor. Classification Substrate MTases can be divided into three different groups on the basis of the chemical reactions they catalyze: * m6A - those that generate N6-methyladenine * m4C - those that generate N4-methylcytosine * m5C - those that generate C5-methylcytosine m6A and m4C methyltransferases are found primarily in prokaryotes (although recent evidence has suggested that m6A is abundant in eukaryotes). m5C methyltransferases are found in some lower eukaryotes, in most higher plants, and in animals beginning with the echinoderms. The m6A methyltransferases (N-6 adenine-specific DNA methylase) (A-Mtase) are enzymes that specifically methylate the amino group at the C-6 position of adenines ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Egr1
EGR-1 (Early growth response protein 1) or NGFI-A (nerve growth factor-induced protein A) is a protein that in humans is encoded by the ''EGR1'' gene. EGR-1 is a mammalian transcription factor. It was also named Krox-24, TIS8, and ZENK. It was originally discovered in mice. Function The protein encoded by this gene belongs to the EGR family of Cys2His2-type zinc finger proteins. It is a nuclear protein and functions as a transcriptional regulator. The products of target genes it activates are required for differentiation and mitogenesis. Studies suggest this is a tumor suppressor gene. It has a distinct pattern of expression in the brain, and its induction has been shown to be associated with neuronal activity. Several studies suggest it has a role in neuronal plasticity. EGR-1 is an important transcription factor in memory formation. It has an essential role in brain neuron epigenetic reprogramming. EGR-1 recruits the TET1 protein that initiates a pathway of DNA demethy ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Promoter (genetics)
In genetics, a promoter is a sequence of DNA to which proteins bind to initiate transcription of a single RNA transcript from the DNA downstream of the promoter. The RNA transcript may encode a protein (mRNA), or can have a function in and of itself, such as tRNA or rRNA. Promoters are located near the transcription start sites of genes, upstream on the DNA (towards the 5' region of the sense strand). Promoters can be about 100–1000 base pairs long, the sequence of which is highly dependent on the gene and product of transcription, type or class of RNA polymerase recruited to the site, and species of organism. Overview For transcription to take place, the enzyme that synthesizes RNA, known as RNA polymerase, must attach to the DNA near a gene. Promoters contain specific DNA sequences such as response elements that provide a secure initial binding site for RNA polymerase and for proteins called transcription factors that recruit RNA polymerase. These transcription factor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
