Related topics: brain · nerve cells · current biology · retina

Gene found that causes eyes to wither in cavefish

Mexican cavefish spend their entire lives in the dark. With no need for vision, many of them lost functional eyes. In more than 30 varieties of Mexican cavefish, the eyes stop developing as embryos grow into larvae. Although ...

Coming to a sky near you: Comet SWAN at its best

Comet C/2020 F8 (SWAN), perhaps the brightest comet we will see this year, is at its best from now until mid-June. It should be visible in from the UK in the northwestern sky after sunset, close to the horizon.

New insights into vitamin A recycling and daytime vision

Many people remember been told as kids when they refused to eat their vegetables that "carrots are good for your eyes." Although parents may not have fully understood it at the time, there is some truth to this. Carrots are ...

In the far future, the universe will be mostly invisible

If you look out on the sky on a nice clear dark night, you'll see thousands of intense points of light. Those stars are incredibly far away, but bright enough to be seen with the naked eye from that great distance—a considerable ...

An artificial 'tongue' of gold to taste maple syrup

It's said that maple syrup is Quebec's liquid gold. Now scientists at Université de Montréal have found a way to use real gold—in the form of nanoparticles—to quickly find out how the syrup tastes.

Hubble captures breakup of comet ATLAS

The NASA/ESA Hubble Space Telescope has provided astronomers with the sharpest view yet of the breakup of Comet C/2019 Y4 (ATLAS). The telescope resolved roughly 30 fragments of the fragile comet on 20 April and 25 pieces ...

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Eyes are organs that detect light, and send signals along the optic nerve to the visual and other areas of the brain[citation needed]. Complex optical systems with resolving power have come in ten fundamentally different forms, and 96% of animal species possess a complex optical system. Image-resolving eyes are present in cnidaria, molluscs, chordates, annelids and arthropods.

The simplest "eyes", such as those in unicellular organisms, do nothing but detect whether the surroundings are light or dark, which is sufficient for the entrainment of circadian rhythms. From more complex eyes, retinal photosensitive ganglion cells send signals along the retinohypothalamic tract to the suprachiasmatic nuclei to effect circadian adjustment.

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