Lateral inhibition

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Lateral inhibition is a mechanism by which neurons are able to determine more precisely the origin of a stimulus.

When, for instance, the skin is touched by an object, several sensory neurons in the skin next to one another are stimulated. To determine more exactly the origin of the stimulus, neurons that are stimulated suppress the stimulation of neighbouring neurons. The amount of inhibition is greater when its own stimulation is more powerful. By doing so, only the neurons that are stimulated will fire. These neurons are more in the center of the stimulus, while the suppressed neurons lie sidewards. hence, lateral inhibition.

Lateral inhibition can be compared with increasing the contrast in images. This phenomenon occurs in the mammalian retina, for example. In the dark, a small light stimulus will be enhanced by the different photoreceptors (rods). 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.

Embryology

Lateral inhibition 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

See also

External links

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