Bright lights, not-so-big pupils

piggy submitted, created time 5 days 19 minutes (www.eurekalert.org)

A team of Johns Hopkins neuroscientists has worked out how some newly discovered light sensors in the eye detect light and communicate with the brain. The report appears online this week in Nature.

These light sensors are a small number of nerve cells in the retina that contain melanopsin molecules. Unlike conventional light-sensing cells in the retina—rods and cones—melanopsin-containing cells are not used for seeing images; instead, they monitor light levels to adjust the body's clock and control constriction of the pupils in the eye, among other functions

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Simple Eyes of Only Two Cells Guide Marine Zooplankton to the Light

piggy submitted, created time 1 month 2 weeks (www.sciencedaily.com)

Researchers unravel how the very first eyes in evolution might have worked and how they guide the swimming of marine plankton towards light.

Larvae of marine invertebrates – worms, sponges, jellyfish - have the simplest eyes that exist. They consist of no more than two cells: a photoreceptor cell and a pigment cell. These minimal eyes, called eyespots, resemble the "proto-eyes" suggested by Charles Darwin as the first eyes to appear in animal evolution. They cannot form images but allow the animal to sense the direction of light

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Light Triggers New Code for Brain Cells

piggy submitted, created time 1 month 3 weeks (www.sciencedaily.com)

Brain cells can adopt a new chemical code in response to cues from the outside world, scientists working with tadpoles at the University of California, San Diego report in the journal Nature.

The discovery opens the possibility that brain chemistry could be selectively altered by stimulating specific circuits to remedy low levels of neural chemicals that underlie some human ailments.

Dark tadpoles don pale camouflage when exposed to bright light

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Metamaterials make hidden doorways possible

Darkfrog submitted, created time 3 months 2 weeks (www.nature.com)

In a writeup rife with references to Harry Potter and Lord of the Rings, Nature writer Dr. Philip Ball speaks of the possibility of creating hidden entranceways similar to the railway platform 9 3/4 from J.K. Rowling's books.

Chinese teams are calling them "superscatterers." The amazing thing that it isn't a cat with epilepsy; it's an object that can bend light to make itself appear bigger than it is. A pillar placed in the middle of a doorway could appear to fill the entire space while in fact leaving openings to each side

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Eyeless Worm Senses Light

sea-maid submitted, created time 5 months 4 weeks (sciencenow.sciencemag.org)

Discovery of light-responsive neurons in a nematode may hold clues about eye evolution.

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Love can be seen in a different light

Sue Wu submitted, created time 8 months 3 days (sciencenow.sciencemag.org)

For people, ultraviolet B (UVB) is an invisible, cancer-causing ray to be blocked with sunscreen and dark glasses, but for a species of jumping spider, the light sets a romantic mood.

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Circadian control by the reduction/oxidation pathway: Catalase represses light-dependent clock gene expression in the zebrafish

sumsung submitted, created time 1 year 3 months (www.pnas.org)

Light is the key entraining stimulus for the circadian clock, but several features of the signaling pathways that convert the photic signal to clock entrainment remain to be deciphered. Here, we show that light induces the production of hydrogen peroxide (H2O2) that acts as the second messenger coupling photoreception to the zebrafish circadian clock.

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