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Electrophysiologists
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] |
Electron
The electron (, or in nuclear reactions) is a subatomic particle with a negative one elementary charge, elementary electric charge. It is a fundamental particle that comprises the ordinary matter that makes up the universe, along with up quark, up and down quark, down quarks. Electrons are extremely lightweight particles that orbit the positively charged atomic nucleus, nucleus of atoms. Their negative charge is balanced by the positive charge of protons in the nucleus, giving atoms their overall electric charge#Charge neutrality, neutral charge. Ordinary matter is composed of atoms, each consisting of a positively charged nucleus surrounded by a number of orbiting electrons equal to the number of protons. The configuration and energy levels of these orbiting electrons determine the chemical properties of an atom. Electrons are bound to the nucleus to different degrees. The outermost or valence electron, valence electrons are the least tightly bound and are responsible for th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ion Current
Ion channels are pore-forming membrane proteins that allow ions to pass through the channel pore. Their functions include establishing a resting membrane potential, shaping action potentials and other electrical signals by gating the flow of ions across the cell membrane, controlling the flow of ions across secretory and epithelial cells, and regulating cell volume. Ion channels are present in the membranes of all cells. Ion channels are one of the two classes of ionophoric proteins, the other being ion transporters. The study of ion channels often involves biophysics, electrophysiology, and pharmacology, while using techniques including voltage clamp, patch clamp, immunohistochemistry, X-ray crystallography, fluoroscopy, and RT-PCR. Their classification as molecules is referred to as channelomics. Basic features There are two distinctive features of ion channels that differentiate them from other types of ion transporter proteins: # The rate of ion transport through the c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kirlian Photography
Kirlian photography is a collection of photographic techniques used to capture the phenomenon of electrical coronal discharges. It is named after Soviet scientist Semyon Kirlian, who, in 1939, accidentally discovered that if an object on a photographic plate is connected to a high-voltage source, an image is produced on the photographic plate.Julie McCarron-Benson in ''Skeptical - a Handbook of Pseudoscience and the Paranormal'', ed Donald Laycock, David Vernon, Colin Groves, Simon Brown, Imagecraft, Canberra, 1989, , p11 The technique has been variously known as "electrography", "electrophotography", "corona discharge photography" (CDP), "bioelectrography", "gas discharge visualization (GDV)", "electrophotonic imaging (EPI)", and, in Russian literature, "Kirlianography". Kirlian photography has been the subject of scientific research, parapsychology research, and art. Paranormal claims have been made about Kirlian photography, but these claims are rejected by the scientific co ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Word Sense
In linguistics, a word sense is one of the meanings of a word. For example, a dictionary may have over 50 different senses of the word "play", each of these having a different meaning based on the context of the word's usage in a sentence, as follows: In each sentence different collocates of "play" signal its different meanings. People and computers, as they read words, must use a process called word-sense disambiguationR. Navigli''Word Sense Disambiguation: A Survey'' ACM Computing Surveys, 41(2), 2009, pp. 1-69. to reconstruct the likely intended meaning of a word. This process uses context to narrow the possible senses down to the probable ones. The context includes such things as the ideas conveyed by adjacent words and nearby phrases, the known or probable purpose and register of the conversation or document, and the orientation (time and place) implied or expressed. The disambiguation is thus context-sensitive. Advanced semantic analysis has resulted in a sub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
-graphy
The English suffix -graphy means a "field of study" or related to "writing" a book, and is an anglicization of the French inherited from the Latin , which is a transliterated direct borrowing from Greek. Arts * Cartography – the art and field of making maps. * Choreography – the art of creating and arranging dances or ballets. * Cinematography – the art of making lighting and camera choices when recording photographic images for the cinema. * Collagraphy - In printmaking, a fine art technique in which collage materials are used as ink-carrying imagery on a printing plate. * Iconography – the art of interpreting the content by icons. * Klecksography – the art of making images from inkblots. * Lexicography – the study lexicons and the art of compiling dictionaries. * Lithography Lithography () is a planographic method of printing originally based on the miscibility, immiscibility of oil and water. The printing is from a stone (lithographic limestone ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Amperometry
Amperometry in chemistry is the detection of ions in a solution based on electric current or changes in electric current. Amperometry is used in electrophysiology to study vesicle release events using a carbon fiber electrode. Unlike patch clamp techniques, the electrode used for amperometry is not inserted into or attached to the cell but brought nearby of the cell. The measurements from the electrode originate from an oxidizing reaction of a vesicle cargo released into the medium. Another technique used to measure vesicle release is capacitive measurements. It is the electric current measured between a pair of electrodes. The measured current is directly proportional to the concentration of the analyte. Example: Blood glucose monitor Carbon is used as a working electrode which is coated with mediator and glucose oxidase. Ag/AgCl is used as the reference electrode. The enzyme oxidase catalyzes the reaction of glucose with oxygen. Hydrogen peroxide concentration is measured b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Local Field Potentials
Local field potentials (LFP) are transient electrical signals generated in nerves and other tissues by the summed and synchronous electrical activity of the individual cells (e.g. neurons) in that tissue. LFP are "extracellular" signals, meaning that they are generated by transient imbalances in ion concentrations in the spaces outside the cells, that result from cellular electrical activity. LFP are 'local' because they are recorded by an electrode placed nearby the generating cells. As a result of the Inverse-square law, such electrodes can only 'see' potentials in a spatially limited radius. They are 'potentials' because they are generated by the voltage that results from charge separation in the extracellular space. They are 'field' because those extracellular charge separations essentially create a local electric field. LFP are typically recorded with a high-impedance microelectrode placed in the midst of the population of cells generating it. They can be recorded, for exam ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Multielectrode Array
Microelectrode arrays (MEAs) (also referred to as multielectrode arrays) are devices that contain multiple (tens to thousands) microelectrodes through which neural signals are obtained or delivered, essentially serving as neural interfaces that connect neurons to electronic circuitry. There are two general classes of MEAs: implantable MEAs, used ''in vivo'', and non-implantable MEAs, used ''in vitro''. In each class, there are rigid, flexible, and stretchable microelectrode array. Theory Neurons and muscle cells create ion currents through their membranes when excited, causing a change in voltage between the inside and the outside of the cell. When recording, the electrodes on an MEA transduce the change in voltage from the environment carried by ions into currents carried by electrons (electronic currents). When stimulating, electrodes transduce electronic currents into ionic currents through the media. This triggers the voltage-gated ion channels on the membranes of the excit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Single-unit Recording
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. 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 interfa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Patch Clamp
The patch clamp technique is a laboratory technique in electrophysiology used to study ionic currents in individual Cell isolation, isolated living cells, tissue sections, or patches of cell membrane. The technique is especially useful in the study of excitable cells such as neurons, cardiomyocytes, muscle fibers, and pancreas, pancreatic beta cells, and can also be applied to the study of bacterial ion channels in specially prepared giant spheroplasts. Patch clamping can be performed using the voltage clamp technique. In this case, the voltage across the cell membrane is controlled by the experimenter and the resulting currents are recorded. Alternatively, the Electrophysiology, current clamp technique can be used. In this case, the current passing across the membrane is controlled by the experimenter and the resulting changes in voltage are recorded, generally in the form of action potentials. Erwin Neher and Bert Sakmann developed the patch clamp in the late 1970s and earl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Intracellular
This glossary of biology terms is a list of definitions of fundamental terms and concepts used in biology, the study of life and of living organisms. It is intended as introductory material for novices; for more specific and technical definitions from sub-disciplines and related fields, see Glossary of cell biology, Glossary of genetics, Glossary of evolutionary biology, Glossary of ecology, Glossary of environmental science and Glossary of scientific naming, or any of the organism-specific glossaries in :Glossaries of biology. A B C D E ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
