Lateral inhibition
Encyclopedia
In neurobiology, lateral inhibition is the capacity of an excited neuron
to reduce the activity of its neighbors. Lateral inhibition sharpens the spatial profile of excitation in response to a localized stimulus.
, in his book Sensory Inhibition, 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 creates the Mach band visual effect.
Artificial lateral inhibition has been incorporated into artificial sensory systems, such as vision chips, hearing systems, and optical mice.
Sensory inhibition in vision was inferred by Ernst Mach
in 1865.
Inhibition in single sensory neurons was discovered and investigated starting in 1949 by Hartline,
and 1956 by Hartline, Wagner, and Ratliff.
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.
Neuron
A neuron is an electrically excitable cell that processes and transmits information by electrical and chemical signaling. Chemical signaling occurs via synapses, specialized connections with other cells. Neurons connect to each other to form networks. Neurons are the core components of the nervous...
to reduce the activity of its neighbors. Lateral inhibition sharpens the spatial profile of excitation in response to a localized stimulus.
Sensory inhibition
Georg von BékésyGeorg von Békésy
Georg von Békésy was a Hungarian biophysicist born in Budapest, Hungary.In 1961, he was awarded the Nobel Prize in Physiology or Medicine for his research on the function of the cochlea in the mammalian hearing organ.-Research:Békésy developed a method for dissecting the inner ear of human...
, in his book Sensory Inhibition, 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
Contrast (vision)
Contrast is the difference in visual properties that makes an object distinguishable from other objects and the background. In visual perception of the real world, contrast is determined by the difference in the color and brightness of the object and other objects within the same field of view...
and sharpness in visual response. This phenomenon occurs in the mammalian retina
Retina
The vertebrate retina is a light-sensitive tissue lining the inner surface of the eye. The optics of the eye create an image of the visual world on the retina, which serves much the same function as the film in a camera. Light striking the retina initiates a cascade of chemical and electrical...
, 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
Signal transduction
Signal transduction occurs when an extracellular signaling molecule activates a cell surface receptor. In turn, this receptor alters intracellular molecules creating a response...
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 creates the Mach band visual effect.
Artificial lateral inhibition has been incorporated into artificial sensory systems, such as vision chips, hearing systems, and optical mice.
History
The concept of neural inhibition (in motor systems) was well known to Descartes and his contemporaries.Sensory inhibition in vision was inferred by Ernst Mach
Ernst Mach
Ernst Mach was an Austrian physicist and philosopher, noted for his contributions to physics such as the Mach number and the study of shock waves...
in 1865.
Inhibition in single sensory neurons was discovered and investigated starting in 1949 by Hartline,
and 1956 by Hartline, Wagner, and Ratliff.
Embryology
In embryology, the concept of lateral inhibition has been adapted to describe processes in the development of cell types. 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.