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an investigation of the component parts of a whole and their relations in making up the whole
the abstract separation of a whole into its constituent parts in order to study the parts and their relations (同)analytic thinking
a branch of mathematics involving calculus and the theory of limits; sequences and series and integration and differentiation
a form of literary criticism in which the structure of a piece of writing is analyzed
the use of closed-class words instead of inflections: e.g., `the father of the bride instead of `the brides father
of or relating to a quantum or capable of existing in only one of two states (同)quantized

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(内容・状況などの)『分析』,分解;(詳細な)検討 / (化学・物理で)分析;《米》(心理学で)[精神]分析;(数学で)解析
quantumの複数形

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出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2015/12/26 15:58:27」(JST)

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This single EPSP does not sufficiently depolarize the membrane to generate an action potential.

The summation of these three EPSPs generates an action potential.

In neuroscience, an excitatory postsynaptic potential (EPSP) is a postsynaptic potential that makes the 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. 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. Larger EPSPs result in greater membrane depolarization and thus increase the likelihood that the postsynaptic cell reaches the threshold for firing an action potential.

Overview

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. 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. The Excitatory graphs to the right need amendment as the Threshold Potential is -55mV so the so-called failure would actually lead to AP. The scale just needs altering to something more reasonable.

Excitatory molecules

The neurotransmitter most often associated with EPSPs is the amino acid glutamate, and is the main excitatory neurotransmitter in the central nervous system of vertebrates.^[1] Its ubiquity at excitatory synapses has led to it being called the excitatory neurotransmitter. In some invertebrates, glutamate is the main excitatory transmitter at the neuromuscular junction.^[2]^[3] In the neuromuscular junction of vertebrates, EPP (end-plate potentials) are mediated by the neurotransmitter acetylcholine, which (along with glutamate) is one of the primary transmitters in the central nervous system of invertebrates.^[4] At the same time, GABA is the most common neurotransmitter associated with IPSPs in the brain. However, classifying neurotransmitters as such is technically incorrect, as there are several other synaptic factors that help determine a neurotransmitter's excitatory or inhibitory effects.

Miniature EPSPs and quantal analysis

The release of neurotransmitter vesicles from the presynaptic cell is probabilistic. In fact, even without stimulation of the presynaptic cell, a single vesicle will occasionally be released into the synapse, generating miniature EPSPs (mEPSPs). Bernard Katz pioneered the study of these mEPSPs at the neuromuscular junction (often called miniature end-plate potentials^[5]) in 1951, revealing the quantal nature of synaptic transmission. Quantal size can then be defined as the synaptic response to the release of neurotransmitter from a single vesicle, while quantal content is the number of effective vesicles released in response to a nerve impulse.^{[citation needed]} Quantal analysis refers to the methods used to deduce, for a particular synapse, how many quanta of transmitter are released and what the average effect of each quantum is on the target cell, measured in terms of amount of ions flowing (charge) or change in the membrane potential.^[6]

Field EPSPs

EPSPs are usually recorded using intracellular electrodes. The extracellular signal from a single neuron is extremely small and thus next to impossible to record in the human brain. However, in some areas of the brain, such as the hippocampus, neurons are arranged in such a way that they all receive synaptic inputs in the same area. Because these neurons are in the same orientation, the extracellular signals from synaptic excitation don't cancel out, but rather add up to give a signal that can easily be recorded with a field electrode. This extracellular signal recorded from a population of neurons is the field potential. In studies of hippocampal long-term potentiation (LTP), figures are often given showing the field EPSP (fEPSP) in stratum radiatum of CA1 in response to Schaffer collateral stimulation. This is the signal seen by an extracellular electrode placed in the layer of apical dendrites of CA1 pyramidal neurons. The Schaffer collaterals make excitatory synapses onto these dendrites, and so when they are activated, there is a current sink in stratum radiatum: the field EPSP. The voltage deflection recorded during a field EPSP is negative-going, while an intracellularly recorded EPSP is positive-going. This difference is due to the relative flow of ions (primarily the sodium ion) into the cell, which, in the case of the field EPSP is away from the electrode, while for an intracellular EPSPs it is towards the electrode. After a field EPSP, the extracellular electrode may record another change in electrical potential named the population spike which corresponds to the population of cells firing action potentials (spiking). In other regions than CA1 of the hippocampus, the field EPSP may be far more complex and harder to interpret as the source and sinks are far less defined. In regions such as the striatum, neurotransmitters such as dopamine, acetylcholine, GABA and others may also be released and further complicate the interpretation.

References

^ Meldrum, BS (Apr 2000). "Glutamate as a neurotransmitter in the brain: review of physiology and pathology.". The Journal of nutrition 130 (4S Suppl): 1007S–15S. PMID 10736372.
^ Keshishian, H; Broadie K; Chiba A; Bate M (1996). "The Drosophila Neuromuscular Junction: A Model System for Studying Synaptic Development and Function". Ann. Rev. Neurosci. 19: 545–575. doi:10.1146/annurev.ne.19.030196.002553. PMID 8833454.
^ Samoilova, MV; Frolova, EV; Potapjeva, NN; Fedorova, IM; Gmiro, VE; Magazanik, LG (September 1997). "Channel blocking drugs as tools to study glutamate receptors in insect muscles and molluscan neurons". Invertebrate Neuroscience 3 (2–3): 117–126. doi:10.1007/BF02480366.
^ http://www.wormbook.org/chapters/www_neuronalgenome/neuronalgenome.html
^ Functionally, mEPSPs and miniature end-plate potentials (mEPPs) are identical. The name end-plate potential is used since Katz's studies were performed on the neuromuscular junction, the muscle fiber component of which is commonly called the motor end-plate.
^ "2001-2002 M.R. Bauer Foundation Colloquium Series". Bio.brandeis.edu. Retrieved 2014-01-22.

External links

Quantal transmission at neuromuscular synapses

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English Journal

Simultaneous confidence bands for low-dose risk estimation with quantal data.

Peng J1, Robichaud M, Alsubie AQ.
Biometrical journal. Biometrische Zeitschrift.Biom J.2014 May 19. doi: 10.1002/bimj.201300250. [Epub ahead of print]
Risk assessment studies where human, animal or ecological data are used to set safe low dose levels of a toxic agent are challenging as study information is limited to high dose levels of the agent. Simultaneous hyperbolic confidence bands for low-dose risk estimation with quantal data have been pro
PMID 24838310

miR-8 controls synapse structure by repression of the actin regulator Enabled.

Loya CM1, McNeill EM, Bao H, Zhang B, Van Vactor D.
Development (Cambridge, England).Development.2014 May;141(9):1864-74. doi: 10.1242/dev.105791. Epub 2014 Apr 9.
MicroRNAs (miRNAs) are post-transcriptional regulators of gene expression that play important roles in nervous system development and physiology. However, our understanding of the strategies by which miRNAs control synapse development is limited. We find that the highly conserved miRNA miR-8 regulat
PMID 24718988

Activity-dependent regulation of release probability at excitatory hippocampal synapses: a crucial role of fragile X mental retardation protein in neurotransmission.

Wang XS1, Peng CZ, Cai WJ, Xia J, Jin D, Dai Y, Luo XG, Klyachko VA, Deng PY.
The European journal of neuroscience.Eur J Neurosci.2014 May;39(10):1602-12. doi: 10.1111/ejn.12546. Epub 2014 Mar 20.
Transcriptional silencing of the Fmr1 gene encoding fragile X mental retardation protein (FMRP) causes fragile X syndrome (FXS), the most common form of inherited intellectual disability and the leading genetic cause of autism. FMRP has been suggested to play important roles in regulating neurotrans
PMID 24646437

Japanese Journal

Dynamic Quantum Isotope Effects on Multiple Proton-Transfer Reactions

Shigeta Yasuteru,Miyachi Hideaki,Matsui Toru,Hirao Kimihiko
Bulletin of the Chemical Society of Japan 81(10), 1230-1240, 2008
… In order to investigate static quantum isotope effects on the stability of proton-transferred structures, we defined an effective quantal potential energy hypersurface (EQPES), which includes mass-dependent quantum effects. … We also performed the EQPES analysis of model proton-transfer reactions in DNA base pairs. … In order to investigate dynamic quantum isotope effects on the stability of the proton-transferred structures, we performed quantal cumulant dynamics (QCD) simulations of the GC pair. …
NAID 130004058843