The hidden light: My new brain column in Discover

Posted on by Matt Kristoffersen

We can see because neurons in our eyes take in visible light and relay electric signals to the brain. But some of the neurons in our retinas detect light that we cannot actually see. In fact, people who lose all their other retinal cells except these neurons are blind. If you shine a light in their eyes and ask them to guess the color, however, they guess very well. It turns out these neurons feed this invisible light to many parts of the brain. In my latest column for Discover, I take a look at this hidden light. Check it out.

[Image: Billy Rowlinson on Flickr via Creative Commons]

Originally published February 17, 2012. Copyright 2012 Carl Zimmer.

Flies and booze: strictly for medicinal purposes

Posted on by Matt Kristoffersen

One mission of the Loom is to champion unjustly neglected forms of life. And so I spend a lot of time blogging about the sinister powers of parasites. But I don’t want to leave you with the impression that hosts are simply helpless bags of grub. Hosts have evolved defenses to ward off parasites, and those defenses can be just as baroque and marvelous as the adaptations of their parasites.

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To Evict Parasite, Canny Fruit Flies Pick Their Poison

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The New York Times, February 16, 2012

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Fruit flies may seem as if they lead an uneventful life. They look for old fruit to lay their eggs. The maggots then hatch and graze on the yeast and bacteria that make the fruit rot.

In reality, however, these flies have to do battle with horrifying enemies. Tiny wasps seek out the maggots and lay eggs inside them. The wasps develop inside the still living flies, feeding on their tissues. When the wasps reach adult size, they crawl out of the dying bodies of their hosts.

The flies are not helpless victims, however. In the journal Current Biology, Todd Schlenke, an Emory University biologist, and his colleagues report a remarkable defense the insects use: To kill their parasites, the flies get drunk.

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Our Strange, Important, Subconscious Light Detectors

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Discover, February 15, 2012

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There was no way the blind mice could see, yet somehow, they could. The year was 1923, and a Harvard grad student named Clyde Keeler had set out to compare eyes from different animals, starting with mice that he bred in his dorm room. Keeler cut open one mouse’s eye and put it under a microscope. Immediately he realized something was wrong. Missing from the eye was the layer of rods and cones, the photoreceptors that catch light. Turning back to his colony, Keeler realized that half of his animals were blind. Somehow a mutation had arisen, wiping out their rods and cones.

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