News tagged with retina

Related topics: cells · brain · eye · neurons · stem cells

New drug could help AMD sufferers

There is no cure for age-related macular degeneration, an eye disease that is the leading cause of vision loss and blindness in older Americans. Last year, the National Institutes of Health reported that two drugs injected ...

Jun 18, 2013
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Temporal processing in the olfactory system

The neural machinery underlying our olfactory sense continues to be an enigma for neuroscience. A recent review in Neuron seeks to expand traditional ideas about how neurons in the olfactory bulb might encode information ...

May 17, 2013
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One-two punch could be key in treating blindness

Researchers have discovered that using two kinds of therapy in tandem may be a knockout combo against inherited disorders that cause blindness. While their study focused on man's best friend, the treatment could help restore ...

Apr 09, 2013
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How rats see things

The image of an object, when projected into the eyes, may take on the most diverse shapes depending on the chosen point of view, as this can change its distance, perspective and so on, yet generally we have no difficulty ...

Apr 04, 2013
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New view of origins of eye diseases

Using new technology and new approaches, researchers at Lund University in Sweden hope to be able to explain why people suffer vision loss in eye diseases such as retinal detachment and glaucoma.

Apr 03, 2013
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Switching night vision on or off

Neurobiologists at the Friedrich Miescher Institute have been able to dissect a mechanism in the retina that facilitates our ability to see both in the dark and in the light. They identified a cellular switch that activates ...

Mar 27, 2013
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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 events that ultimately trigger nerve impulses. These are sent to various visual centers of the brain through the fibers of the optic nerve.

In vertebrate embryonic development, the retina and the optic nerve originate as outgrowths of the developing brain, so the retina is considered part of the central nervous system (CNS).. It is the only part of the CNS that can be imaged non-invasively in the living organism.

The retina is a complex, layered structure with several layers of neurons interconnected by synapses. The only neurons that are directly sensitive to light are the photoreceptor cells. These are mainly of two types: the rods and cones. Rods function mainly in dim light and provide black-and-white vision, while cones support daytime vision and the perception of colour. A third, much rarer type of photoreceptor, the photosensitive ganglion cell, is important for reflexive responses to bright daylight.

Neural signals from the rods and cones undergo complex processing by other neurons of the retina. The output takes the form of action potentials in retinal ganglion cells whose axons form the optic nerve. Several important features of visual perception can be traced to the retinal encoding and processing of light.

This text uses material from Wikipedia, licensed under CC BY-SA

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