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Mass Action Principle (neuroscience)
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. Early theories In the 19th century, animal researchers and scientists were divided into two main groups in terms of how they believe the brain compensated for induced brain damage. The redundancy theorists hypothesized that any lesioned section of cerebral mass had an almost duplicate section, usually on the opposing hemisphere. This "back-up" area was considered to be what takes over the functions of the lesioned area. On the other hand, vicariation theorists believed that different areas of the brain with different functions co ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Functional Specialization (brain)
In neuroscience, functional specialization is a theory which suggests that different areas in the brain are specialized for different functions.Flourens, M. J. P. (1824) Recherces experimentales sur les propretes et les fonctions du systeme nerveux dans les animaux vertebres. Paris: J.B. Balliere.Lashley, K. S. (1929) Brain mechanisms and intelligence. Chicago: Chicago University Press. Historical origins Phrenology, created by Franz Joseph Gall (1758–1828) and Johann Gaspar Spurzheim (1776–1832) and best known for the idea that one's personality could be determined by the variation of bumps on their skull, proposed that different regions in one's brain have different functions and may very well be associated with different behaviours. Gall and Spurzheim were the first to observe the crossing of pyramidal tracts, thus explaining why lesions in one hemisphere are manifested in the opposite side of the body. However, Gall and Spurzheim did not attempt to justify phrenolo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Karl Lashley
Karl Spencer Lashley (June 7, 1890 – August 7, 1958) was a psychologist and behaviorist remembered for his contributions to the study of learning and memory. A ''Review of General Psychology'' survey, published in 2002, ranked Lashley as the 61st most cited psychologist of the 20th century. Early life and education Lashley was born on June 7, 1890 in the town of Davis, West Virginia. He was the only child of Charles and Maggie Lashley. He grew up in a middle-class family with a reasonably comfortable life. Lashley's father held various local political positions. His mother was a stay-at-home parent, and had a vast collection of books in the home. She brought in women from the community, whom she would teach various subjects. This is no doubt what gave Lashley his love of learning. Lashley has always held his family in high regard. He has said that his father was a kind man. Lashley's mother was a strong advocate of schooling, and she encouraged Lashley intellectually from an ea ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Equipotentiality
Equipotentiality refers to a psychological theory in both neuropsychology and behaviorism. Karl Spencer Lashley defined equipotentiality as "The apparent capacity of any intact part of a functional brain to carry out… the emoryfunctions which are lost by the destruction of ther parts.Fancher, R.E., & Rutherford, A. (2012). Pioneers of Psychology. New York, NY: W.W. Norton & Company, Inc. In other words, the brain can co-opt other areas to take over the role of the damaged part.Garrett, H. (1941). R. Elliott (Ed.), Great experiments in psychology, New York: D. Appleton-century Company. Equipotentiality is subject to the other term Lashley coined, the law of mass action. The law of mass action says that the efficiency of any complex function of the brain is reduced proportionately to how much damage the brain as a whole has sustained, but not to the damage of any particular area of the brain. In this context when we use our brains we are referring to the cortex. Historical context ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neuroplasticity
Neuroplasticity, also known as neural plasticity, or brain plasticity, is the ability of Neural circuit, neural networks in the brain to change through growth and reorganization. It is when the brain is rewired to function in some way that differs from how it previously functioned. These changes range from individual neuron pathways making new connections, to systematic adjustments like cortical remapping. Examples of neuroplasticity include circuit and network changes that result from learning a new ability, environmental influences, practice, and psychological stress. Neuroplasticity was once thought by neuroscientists to manifest only during childhood, but research in the latter half of the 20th century showed that many aspects of the brain can be altered (or are "plastic") even through adulthood. However, the developing brain exhibits a higher degree of plasticity than the adult brain. Activity-dependent plasticity can have significant implications for healthy development, le ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Jean Pierre Flourens
Marie Jean Pierre Flourens (13 April 1794 – 6 December 1867), father of Gustave Flourens, was a French physiologist, the founder of experimental brain science, and a pioneer in anesthesia. Biography Flourens was born at Maureilhan, near Béziers, in the ''département'' of Hérault. At fifteen he began studying medicine at Montpellier, where he received the degree of doctor in 1813. In the following year he went to Paris, carrying an introduction from A. P. de Candolle, the botanist, to Georges Cuvier, who received him kindly, and took an interest in him. In Paris, Flourens engaged in physiological research, occasionally contributing to publications; and, in 1821, at the Athénée, he gave a course of lectures on the physiological theory of the sensations, which attracted much attention amongst men of science. In 1815, Flourens pioneered the experimental method of carrying out localized lesions of the brain in living rabbits and pigeons and carefully observing their effects o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Engram (neuropsychology)
An engram is a unit of cognitive information imprinted in a physical substance, theorized to be the means by which memories are stored as biophysical or biochemical changes in the brain or other biological tissue, in response to external stimuli. Demonstrating the existence of, and the exact mechanism and location of, neurologically defined engrams has been a focus of persistent research for many decades. History The term "engram" was coined by memory researcher Richard Semon in reference to the physical substrate of memory in the organism. Semon warned, however: "In animals, during the evolutionary process, one organic system—the nervous system—has become specialised for the reception and transmission of stimuli. No monopoly of this function by the nervous system, however, can be deduced from this specialisation, not even in its highest state of evolution, as in Man." One of the first ventures on identifying the location of a memory in the brain was undertaken by Karl S. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thomas Willis
Thomas Willis FRS (27 January 1621 – 11 November 1675) was an English doctor who played an important part in the history of anatomy, neurology and psychiatry, and was a founding member of the Royal Society. Life Willis was born on his parents' farm in Great Bedwyn, Wiltshire, where his father held the stewardship of the manor. He was a kinsman of the Willys baronets of Fen Ditton, Cambridgeshire. He graduated M.A. from Christ Church, Oxford in 1642.Willis, Thomas The Galileo Project. Galileo.rice.edu. Retrieved on 17 July 2012. In the Civil War years he was a royalist, dispossessed of the family farm at by Parliamentary forces. In the 1640s, Willis was one of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
François Pourfour Du Petit
François Pourfour du Petit (24 June 1664 – 18 June 1741) was a French anatomist, ophthalmologist and surgeon who conducted careful anatomical studies of the human eye. He also conducted early experiments in neurology. Petit was born in Paris and was orphaned at an early age. He studied the classics at the College de Beauvais before studies in Belgium and Germany. He then studied medicine at the University of Montpellier, and afterwards surgery at the Hôpital de la Charité in Paris. During this period of time he also attended lectures by Guichard Joseph Duverney (1648–1730) in anatomy and Joseph Pitton de Tournefort (1656–1708) in botany. Between 1693 and 1713 he was a military physician in the armies of Louis XIV, and after the Peace of Utrecht (1713), he returned to Paris as an eye specialist. He conducted many cataract surgeries using the technique of displacing the lens using a needle and influenced Jacques Daviel approach to cataract treatment. He made careful measure ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hughlings Jackson
John Hughlings Jackson, FRS (4 April 1835 – 7 October 1911) was an English neurologist. He is best known for his research on epilepsy. Biography He was born at Providence Green, Green Hammerton, near Harrogate, Yorkshire, the youngest son of Samuel Jackson, a brewer and yeoman who owned and farmed his land, and Sarah Jackson (née Hughlings), the daughter of a Welsh revenue collector. His mother died just over a year after giving birth to him. He had three brothers and a sister; his brothers emigrated to New Zealand and his sister married a physician. He was educated at Tadcaster, Yorkshire and Nailsworth, Gloucestershire before attending the York Medical and Surgical School. After qualifying at St Barts in 1856 he became house physician to the York Dispensary. In 1859 he returned to London to work at the Metropolitan Free Hospital and the London Hospital. In 1862 he was appointed Assistant Physician, later (1869) full Physician at the National Hospital for Paralysis and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alexander Bain (philosopher)
Alexander Bain (11 June 1818 – 18 September 1903) was a Scottish philosopher and educationalist in the British school of empiricism and a prominent and innovative figure in the fields of psychology, linguistics, logic, moral philosophy and education reform. He founded ''Mind'', the first ever journal of psychology and analytical philosophy, and was the leading figure in establishing and applying the scientific method to psychology. Bain was the inaugural Regius Chair in Logic and Professor of Logic at the University of Aberdeen, where he also held Professorships in Moral Philosophy and English Literature and was twice elected Lord Rector of the University of Aberdeen. Early life and education Alexander Bain was born in Aberdeen to George Bain, a weaver and veteran soldier, and Margaret Paul. At age eleven he left school to work as a weaver (occupation), weaver hence the description of him as Weevir, ''rex philosophorum''. He also attended lectures at the Mechanics' Insti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electrical Excitability
Electricity is the set of physical phenomena associated with the presence and motion of matter that has a property of electric charge. Electricity is related to magnetism, both being part of the phenomenon of electromagnetism, as described by Maxwell's equations. Various common phenomena are related to electricity, including lightning, static electricity, electric heating, electric discharges and many others. The presence of an electric charge, which can be either positive or negative, produces an electric field. The movement of electric charges is an electric current and produces a magnetic field. When a charge is placed in a location with a non-zero electric field, a force will act on it. The magnitude of this force is given by Coulomb's law. If the charge moves, the electric field would be doing work on the electric charge. Thus we can speak of electric potential at a certain point in space, which is equal to the work done by an external agent in carrying a unit of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gustav Theodor Fritsch
Gustav Theodor Fritsch (5 March 1838 – 12 June 1927) was a German anatomist, anthropologist, traveller and physiologist from Cottbus. Fritsch studied natural science and medicine in Berlin, Breslau and Heidelberg. In 1874 he became an associate professor of physiology at the University of Berlin, where he was later appointed head of the histological department at the physiological institute. He is known for his work with neuropsychiatrist Eduard Hitzig (1839–1907) involving the localization of the motor areas of the brain. In 1870, the two scientists probed the cerebral cortex of a dog to discover that electrical stimulation of different areas of the cerebrum caused involuntary muscular contractions of specific parts of the dog's body. Along with his medical studies, Fritsch was also known for his ethnographical research in southern Africa (1863–66), during which time he traveled from Cape Town through the Orange Free State, Basutoland, Natal and Bechuanaland. In 1 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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