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

Hidden danger from pet dogs in Africa

Dogs in tropical Africa run the risk of contracting canine trypanosomosis if they are bitten by bloodsucking tsetse flies carrying trypanosomes—microscopic, single-celled organisms found in the bloodstream. In dogs, this ...

It's not aurora, it's STEVE

Aurora-watchers gazing at spectacular displays over the Labor Day weekend may have been seeing more than the northern lights. They may have been dazzled by STEVE as well.

Could the Loch Ness monster be a giant eel?

Is the Loch Ness monster a shark? A giant catfish? A sturgeon? No, it's a giant eel! Or at least it could be, according to a study published on Thursday.

NASA catches the eye of Typhoon Lingling

Typhoon Lingling continues to strengthen in the Northwestern Pacific Ocean and NASA's Terra satellite imagery revealed the eye is now visible.

How worms snare their hosts

Acanthocephala are parasitic worms that reproduce in the intestines of various animals, including fish. However, only certain species of fish are suitable as hosts. A study by the University of Bonn now shows how the parasites ...

Nanoparticles could someday give humans built-in night vision

Movies featuring heroes with superpowers, such as flight, X-ray vision or extraordinary strength, are all the rage. But while these popular characters are mere flights of fancy, scientists have used nanoparticles to confer ...

Tracing the evolution of vision in fruit flies

The function of the visual photopigment rhodopsin and its action in the retina to facilitate vision is well understood. However, there remain questions about other biological functions of this family of proteins (opsins) ...

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Eye

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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