News tagged with retina

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

Distribution of photoreceptors in the retina of mice

Guppies, hyenas and mice share one particular retinal specialization in their eye: Photoreceptors ("cones") sensitive to 'green' light are largely located in the top half of the eye, whereas cones sensitive to 'blue' light ...

Dec 05, 2013
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Vision trumps hearing in study

A Duke University study used puppet-based comedy to demonstrate the complicated inner-workings of the brain and shows what every ventriloquist knows: The eye is more convincing than the ear.

Sep 11, 2013
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A vision exam for mice

How can one use simple means to investigate the visual abilities of animals? This question is being pursued by the research group of Dr. Thomas Münch at the Centre for Integrative Neuroscience at the University of Tübingen. ...

Aug 21, 2013
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Beating blindness with vegetable oil

Scientists working at the Research Center on Aging at the Health and Social Services Centre—University Institute of Geriatrics of Sherbrooke (CSSS-IUGS) have been studying strategies for protecting retinal ...

Aug 15, 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