Lateral inhibition


Lateral inhibition

In neurobiology, lateral inhibition is the capacity of an excited neuron to reduce the activity of its neighbors.

ensory inhibition

Georg von Békésy, in his book "Sensory Inhibition", [cite book | title = Sensory Inhibition | author = Georg Von Békésy | year = 1967 | publisher = Princeton University Press ] explores a wide range of inhibitory phenomena in sensory systems, and interprets them in terms of sharpening.

When, for instance, the skin is touched by an object, several sensory neurons in the skin next to one another are stimulated. Neurons that are firing suppress the stimulation of neighbouring neurons. In the face of inhibition, only the neurons that are most stimulated and least inhibited will fire, so the firing pattern tends to concentrate at stimulus peaks.

Lateral inhibition increases the contrast and sharpness in visual response. This phenomenon occurs in the mammalian retina, for example. In the dark, a small light stimulus will be enhanced by the different photoreceptors (rod cells). The rods in the center of the stimulus will transduce the "light" signal to the brain, whereas different rods on the outside of the stimulus will send a "dark" signal to the brain. This contrast between the light and dark creates a sharper image. This mechanism also create the Mach band visual effect.

Artificial lateral inhibition has been incorporated into artificial sensory systems, such as vision chips, [cite book | title = Vision Chips | author = Alireza Moini | publisher = Springer | year = 2000 | ibsn = 0792386647 | url = http://books.google.com/books?id=iuxqcj7IwbYC&pg=PA19&dq=lateral-inhibition+vision+chips&lr=&as_brr=3&ei=WRPFR6OqGYqqswOcoMW4CA&sig=zu_KlfFfMR6kD4TMhK021J8uBaM ] hearing systems, [cite book | title = Artificial Neural Networks: ICANN 96 | author = Christoph von der Malsburg et al. (editors) | publisher = Springer | year = 1996 | ibsn = 3540615105 | url = http://books.google.com/books?id=gp6wX1J4FFoC&pg=PA679&dq=lateral-inhibition+electronic+cochlea&lr=&as_brr=3&ei=GBXFR6eNJYPYsQOgyJigCA&sig=5QhIiXWh6sdNbhsRypmfQhpbjdU#PPA679,M1 ] and optical mice. [cite web | url = http://sl-div-bi-pb.web.cern.ch/sl-div-bi-pb/PrivatePBpage/Electronics/Electronics-Misc/Vision/vis_new.pdf | title = Vision Chips | author = Alireza Moini | year = 1997 ]

History

The concept of neural inhibition dates at least back to Descartes.Fact|date=February 2008 Sensory inhibition in vision was described by Ernst Mach.Fact|date=February 2008 Inhibition in single sensory neurons was discovered and investigated starting in 1949 by Hartline, [cite book | title = Brain Theory: Reprint Volume | author = Gordon L. Shaw and G. Palm (editors) | publisher = World Scientific | year = 1988 | ibsn = 9971504847 | url = http://books.google.com/books?id=Wi549-09eZcC&pg=PA711&dq=lateral-inhibition+hartline+1949&lr=&as_brr=3&ei=HwzFR-jMF46IswOQibmpCA&sig=-VJ2U25-NBow3EmNgz1ui11A_eo ] and 1956 by Hartline, Wagner, and Ratliff. [cite journal | title = Cognitive Psychology and Information Processing: An Introduction | author = Roy Lachman, Janet Lachman, Earl C. Butterfield | publisher = Lawrence ErlbaumAssociates | year = 1979 | isbn = 0898591317 | url = http://books.google.com/books?id=W4GPnZ2qeWkC&pg=PA496&dq=lateral-inhibition+1956&lr=&as_brr=3&ei=t5uKR7_zLZu4sgPhjLTQBQ&sig=kNT9PzKIxI7R12WfL2t2x8JFluc] Lateral inhibition sharpens the spatial profile of excitation in response to a localized stimulus.

Embryology

In embryology, the concept of lateral inhibition has been adapted to describe processes in the development of cell types. [cite journal | title = Biological Pattern Formation Involving Lateral Inhibition | author = Alfred Gierer and Hans Meinhardt | journal = Some Mathematical Questions in Biology VI: Mathematical Aspects of Chemical and Biochemical Problems and Quantum Chemistry | editor = Donald S. Cohen | publisher = American Mathematical Society | date = 1974 | volume = 7 | url = http://books.google.com/books?id=JQ-ME8oY1agC&pg=PA164&dq=embryology++lateral-inhibition+date:0-1995&lr=&as_brr=3&ei=VaGKR-KUGIzitQPomLHQBQ&sig=CD00Ioho1uiE9noFIxw--QxXLhg#PPA163,M1 ] It is a type of cell–cell interaction whereby a cell that adopts a particular fate inhibits its immediate neighbours from doing likewise. Lateral inhibition is well documented in flies, worms and vertebrates. In all of these organisms, the transmembrane proteins Notch and Delta (or their homologues) have been identified as mediators of the interaction

Neuroblast with slightly more Delta protein on its cell surface will inhibit its neighboring cells from becoming neurons. In flies, frogs, and chicks, Delta is found in those cells that will become neurons, while Notch is elevated in those cells that become the glial cells.

ee also

* Mach band
* Cornsweet illusion
* Grid illusion

References

External links

* [http://www.michaelbach.de/ot/lum_herGrid/index.html Refutation of classical explanation of Hermann Grid Illusion]


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