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Grid Cell
A grid cell is a type of neuron within the entorhinal cortex that fires at regular intervals as an animal navigates an open area, allowing it to understand its position in space by storing and integrating information about location, distance, and direction. Grid cells have been found in many animals, including rats, mice, bats, monkeys, and humans. Grid cells were discovered in 2005 by Edvard Moser, May-Britt Moser, and their students Torkel Hafting, Marianne Fyhn, and Sturla Molden at the Centre for the Biology of Memory (CBM) in Norway. They were awarded the 2014 Nobel Prize in Physiology or Medicine together with John O'Keefe for their discoveries of cells that constitute a positioning system in the brain. The arrangement of spatial firing fields, all at equal distances from their neighbors, led to a hypothesis that these cells encode a neural representation of Euclidean space. The discovery also suggested a mechanism for dynamic computation of self-position based on contin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Grid Cell Image V2
Grid, The Grid, or GRID may refer to: Common usage * Cattle grid or stock grid, a type of obstacle is used to prevent livestock from crossing the road * Grid reference, used to define a location on a map Arts, entertainment, and media * News grid, used in communications/public relations Fictional entities * Grid (comics), a fictional character in the DC Comics Universe * Grid (Jotun), Gríðr, a giantess in Norse mythology * The grid, the virtual environment of the game ''Second Life'' * ''The Grid'', the computerized virtual world in which the Tron franchise exists Games and gaming * Nvidia GRID, a cloud gaming platform for Nvidia Tegra products * ''Power Grid'', the English-language edition of the multiplayer German-style board game ''Funkenschlag'' * Grid (series), a series of racing video games developed by Codemasters * Spooks 3 Games - ''The Grid'', a video game based on the television show ''Spooks'' * ''The Grid'' (video game), a 2001 third-person shooter Music * ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lynn Nadel
Lynn Nadel (born November 12, 1942) is an American psychologist who is the Regents' Professor of psychology at the University of Arizona. Nadel specializes in memory, and has investigated the role of the hippocampus in memory formation. Together with John O'Keefe, he coauthored the influential 1978 book ''The Hippocampus as a Cognitive Map'', which defended the theory that the hippocampus learns and stores cognitive maps of portions of space. With Morris Moscovitch, he advanced the multiple trace theory that the hippocampus is always involved in storage and retrieval of episodic memory, but that semantic memory can be established in the neocortex. Nadel received a Ph.D. from McGill University in 1967, and joined the faculty of the University of Arizona in 1985, where he is now an Emeritus Professor of Psychology and Cognitive Science. Nadel, together with John O'Keefe, received the 2006 Grawemeyer Award for their work in identifying the brain's mapping system. He was named rec ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Equilateral Triangle Lattice
In geometry, an equilateral triangle is a triangle in which all three sides have the same length. In the familiar Euclidean geometry, an equilateral triangle is also equiangular; that is, all three internal angles are also congruent to each other and are each 60°. It is also a regular polygon, so it is also referred to as a regular triangle. Principal properties Denoting the common length of the sides of the equilateral triangle as a, we can determine using the Pythagorean theorem that: *The area is A=\frac a^2, *The perimeter is p=3a\,\! *The radius of the circumscribed circle is R = \frac *The radius of the inscribed circle is r=\frac a or r=\frac *The geometric center of the triangle is the center of the circumscribed and inscribed circles *The altitude (height) from any side is h=\frac a Denoting the radius of the circumscribed circle as ''R'', we can determine using trigonometry that: *The area of the triangle is \mathrm=\fracR^2 Many of these quantities have simp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Path Integration
Path integration is the method thought to be used by animals for dead reckoning. History Charles Darwin first postulated an inertially-based navigation system in animals in 1873.The Complete Work of Charles Darwin Online. ''Origin of Certain Instincts'': full text and facsimile Retrieved 28 February 2012 Studies beginning in the middle of the 20th century confirmed that animals could return directly to a starting point, such as a nest, in the absence of and having taken a circuitous outwards journey. This shows that they can use cues to track distance and direction in order t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Attractor Network
An attractor network is a type of recurrent dynamical network, that evolves toward a stable pattern over time. Nodes in the attractor network converge toward a pattern that may either be fixed-point (a single state), cyclic (with regularly recurring states), chaotic (locally but not globally unstable) or random ( stochastic).* Attractor networks have largely been used in computational neuroscience to model neuronal processes such as associative memory* and motor behavior, as well as in biologically inspired methods of machine learning. An attractor network contains a set of ''n'' nodes, which can be represented as vectors in a ''d''-dimensional space where ''n''>''d''. Over time, the network state tends toward one of a set of predefined states on a ''d''-manifold; these are the attractors. Overview In attractor networks, an ''attractor'' (or ''attracting set'') is a closed subset of states ''A'' toward which the system of nodes evolves. A stationary attractor is a state or sets of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phase Precession
Phase precession is a neurophysiological process in which the time of firing of action potentials by individual neurons occurs progressively earlier in relation to the phase of the local field potential oscillation with each successive cycle. In place cells, a type of neuron found in the hippocampal region of the brain, phase precession is believed to play a major role in the neural coding of information. John O'Keefe, who later shared the 2014 Nobel Prize in Physiology or Medicine for his discovery that place cells help form a "map" of the body's position in space, co-discovered phase precession with Michael Recce in 1993. Place cells Pyramidal cells in the hippocampus called place cells play a significant role in self-location during movement over short distances. As a rat moves along a path, individual place cells fire action potentials at an increased rate at particular positions along the path, termed "place fields". Each place cell's maximum firing ratewith action pote ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Medial Septum
The medial septal nucleus (MS) is one of the septal nuclei. Neurons in this nucleus give rise to the bulk of efferents from the septal nuclei. A major projection from the medial septal nucleus terminates in the hippocampal formation. It plays a role in the generation of theta waves in the hippocampus. Specifically, the GABAergic cells of the medial septum that act as theta pacemakers target dentate gyrus The dentate gyrus (DG) is part of the hippocampal formation in the temporal lobe of the brain, which also includes the hippocampus and the subiculum. The dentate gyrus is part of the hippocampal trisynaptic circuit and is thought to contribute t ..., CA3, and CA1 interneurons. Pacemaking MS interneurons express hyperpolarization-activated cyclic nucleotide-gated (HCN) channels which likely, at least partially, mediate their pacemaker properties. It is composed of GABAergic cells, glutamatergic cells, and cholinergic cells. Each cell-type carries out different functions. In ad ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acetylcholine
Acetylcholine (ACh) is an organic chemical that functions in the brain and body of many types of animals (including humans) as a neurotransmitter. Its name is derived from its chemical structure: it is an ester of acetic acid and choline. Parts in the body that use or are affected by acetylcholine are referred to as cholinergic. Substances that increase or decrease the overall activity of the cholinergic system are called cholinergics and anticholinergics, respectively. Acetylcholine is the neurotransmitter used at the neuromuscular junction—in other words, it is the chemical that motor neurons of the nervous system release in order to activate muscles. This property means that drugs that affect cholinergic systems can have very dangerous effects ranging from paralysis to convulsions. Acetylcholine is also a neurotransmitter in the autonomic nervous system, both as an internal transmitter for the sympathetic nervous system and as the final product released by the par ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hippocampal Theta Rhythm
The hippocampus (via Latin from Greek , 'seahorse') is a major component of the brain of humans and other vertebrates. Humans and other mammals have two hippocampi, one in each side of the brain. The hippocampus is part of the limbic system, and plays important roles in the consolidation of information from short-term memory to long-term memory, and in spatial memory that enables navigation. The hippocampus is located in the allocortex, with neural projections into the neocortex in humans, as well as primates. The hippocampus, as the medial pallium, is a structure found in all vertebrates. In humans, it contains two main interlocking parts: the hippocampus proper (also called ''Ammon's horn''), and the dentate gyrus. In Alzheimer's disease (and other forms of dementia), the hippocampus is one of the first regions of the brain to suffer damage; short-term memory loss and disorientation are included among the early symptoms. Damage to the hippocampus can also result from oxygen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Head Direction Cells
Head direction (HD) cells are neurons found in a number of brain regions that increase their firing rates above baseline levels only when the animal's head points in a specific direction. They have been reported in rats, monkeys, mice, chinchillas and bats, but are thought to be common to all mammals, perhaps all vertebrates and perhaps even some invertebrates, and to underlie the "sense of direction". When the animal's head is facing in the cell's "preferred firing direction" these neurons fire at a steady rate (i.e., they do not show adaptation), but firing decreases back to baseline rates as the animal's head turns away from the preferred direction (usually about 45° away from this direction). HD cells are found in many brain areas, including the cortical regions of postsubiculum (also known as the dorsal presubiculum), retrosplenial cortex, and entorhinal cortex, and subcortical regions including the thalamus (the anterior dorsal and the lateral dorsal thalamic nuclei), la ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Autocorrelation Image
Autocorrelation, sometimes known as serial correlation in the discrete time case, is the correlation of a signal with a delayed copy of itself as a function of delay. Informally, it is the similarity between observations of a random variable as a function of the time lag between them. The analysis of autocorrelation is a mathematical tool for finding repeating patterns, such as the presence of a periodic signal obscured by noise, or identifying the missing fundamental frequency in a signal implied by its harmonic frequencies. It is often used in signal processing for analyzing functions or series of values, such as time domain signals. Different fields of study define autocorrelation differently, and not all of these definitions are equivalent. In some fields, the term is used interchangeably with autocovariance. Unit root processes, trend-stationary processes, autoregressive processes, and moving average processes are specific forms of processes with autocorrelation. Au ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
