Blind cave fish can not ZZZ's

Many grad students can sympathize with the blind form of Astyanax mexicanus. Scholars speculate that they only a few hours a night, sleep, because they not simply to rest.

"These fish live in an environment where food is generally scarce and episodic and unpredictable," Richard Borowsky of New York University in a press release from the school. "If you asleep food are a bit of hovering, you are out of luck and a meal."

BLOG: Fish feel pain to

Borowsky and his colleagues Erik Duboué and Alex Keene discovered that sightless form of Astyanax mexicanus (Mexican Mexicanus) needs less sleep as their sighted cousins of the same type. Their observation of fish in the dark can shed light on human sleep disorders.

"In a sense the sleep phenotypes cave fish of people with sleep disorders, are similar to," explained Borowsky. "they go to sleep, but only for relatively short, then they wake up and stay awake for a relatively long period of time."

BLOG: Alcohol exposure makes fish anti-social

"The next individual operation is to identify the genes that change in the cave fish are responsible for sleep." "You good candidates for the genes for insomnia and other sleep disorders in humans would be responsible," said Borowsky.

The researchers noticed first while working on a study looking back in the blind form of fish to breed the Tetra's sleeping habits.

In a study in 2008 in current biology published it that the fish crossing the blind populations of various caves in Northeast Mexico work found again eyes in just one generation. This happened because the different populations have developed independently of the other blindness. Different genetic changes blindness in each population causes, so that if they were crossed offspring was partially restored to see the ability in their.

BLOG: Fish talk to each other

In the course of this study, they noticed that the blind version of Tetra spent less time inactive below their aquariums in the night as their sighted relatives.

How to determine whether what they saw was a real difference in the sleep pattern, they used two methods. One was, wait until the fish were inactive, then type for your aquarium and see if she slow reacting. A slow response meant a sleepy fish.

The other was to deprive the fish to see sleep for a whole night, as they responded the next day. When she took many NAP on the next day, they were interpreted as deprived of sleep.

The sighted fish responded to this torment over her blind cousins.

The researchers found that over a period of 24 hours, an average of more than 800 minutes (over 13 hours) slept sighted fish while blind fish slept only an average 110 to 250 minutes.

To test their observations, the researchers then cross the fish bred. She found that, like blindness, insomnia genetic. The hybrid fish sleep disorders, such as parents were blind. This led the researchers to the conclusion that it was a dominant gene, caused insomnia.

The blind fish were of different population groups. They came from three unrelated Mexican cave systems Pachón, Tinaja and Molino. This is an indication that the fish of the same evolutionary conclusion to a problem arrived by separate genetic ways, a phenomenon known as convergent evolution.

"We a cave associated with phenotype unsuspected until documented now, be that have the basic adaptation of aquatic vertebrates cave entrance could be life," Borowsky said.

Another experiment on the researchers list is exactly what evolutionary forces drove the biological convergence of the different Tetra populations found.

The results from the fish sleep experiment were published in the journal current biology.

Figure 1: Blind and sighted forms of Astyanax mexicanus (courtesy: NYU Press release)

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"Bionic Eye" implant offers hope the blind

An ocular prosthesis is "a gross level of vision" for blind people give. At least a patient improves his ability to interpret the light flashes and identify them as lines and shapes.

Elias k. runs through an optics test with his glasses "bionic" eye during a session in the Lions vision research and Rehabilation Center of the Johns Hopkins University in Baltimore, Maryland. Elias is blind but work with Johns Hopkins University he was implanted with a microchip and given a set of glasses that allow him to distinguish between light and dark.

For a man whose view of the world slowly to black over 30 years has faded a device that's him to see his hope has flashes of light, one day face looks on his grandson enkindled allows.

A career electrician grew of in Greece and in the United States as a young man came, noticed first he could see his vision ever poorer when at the age of 43 on a related glasses tried he absentmindedly and found Elias with them as clear without.

Soon after, he visited a doctor, his eyesight tested and discovered that he could no longer see his outstretched arms from the corners to his eyes. See his peripheral was deteriorating.

He was known as retinitis pigmentosa, which influenced diagnosed 100,000 people or one in 3,000 in the United States with an incurable condition.

A leading form of hereditary blindness, the disease eats gradually away in the retina rods and cones, the photoreceptors, the people help light and color and detail to identify.

About 10 years later could he not more well see enough to keep working.

"You lose your sight, you pretty much lose everything," said Elias, who now last 72 and his little vision five years ago lost.

When his doctor to demand that he attend a three year study of a futuristic technology, an electrode array in his eye and a wireless camera to a few glasses in 2009, Elias was excited to take part.

Now every morning, that he at the glasses, providing a wireless device belt around his waist and stands at the window or on the court waiting to hear the sound of a car approach to. When it comes, he says he go through a block of light can see.

He can distinguish even bright objects against dark backgrounds, and he can orient himself in a room to see, where it is an open window or door let the Sun in from outside.

The device, known as the Argus II, is made by a California company called second sight. It was approved recently for use in Europe, and in the United States there were a handful of test patients such as Elias cause for optimism.

"Without system, I can see anything." With the system, it is a kind of hope. "Something exists, he said."

"Later who with technology knows what it can do?" "Everything is little by little."

The device is similar to the cochlear implants, the hundreds of thousands of deaf people could hear again, and part of a growing field is known as Neuromodulation or science, the people again lost skills such as sight hearing and movement through the stimulation of the brain helps, Spinal cord or nerves.

Ear implants work by through a small microphone captures the sound and then convert these signals into electrical impulses and send implanted at an electrode array in the patients. The electrodes collect the impulses and deliver them to the auditory nerve, who hears it as sounds.

The retinal prosthesis follows a similar process. A tiny video camera on the glasses captures images and convert them into electrical signals which are fed in an electrode array that is surgically implanted in the eye of the patient.

The Visual signals to the brain of the optic nerve and then transmitted, and the patient sees them as flashes of light and blurred shapes.

"It is still a very rough level of vision but it is the beginning of an improvement," said Gislin Dagnelie, a doctor of working with Elias and other blind patients at the Johns Hopkins University in Baltimore, Maryland. "We have to learn to speak like the retina, in fact."

The implant is imperceptible. The operation took about three hours, causing no pain, Elias said.

Having second sight Vice President business development Brian Mech, which had 60 electrodes, compared to an earlier version, the 16 latest generation of technology has.

"Surgery is much shorter and requires only a specialist (Argus I 3 required)," Mech said.

All in all 14 devices are used in the United States and 16 in Europe. The Argus II costs about US $100,000.

The company plans, request a humanitarian device exemption with the food and drug administration and hopes for approval soon in 2012.

In the meantime Elias practices with the device one day a week in the laboratory with Dagnelie. With each meeting, Elias keeps track of objects he sees on a computer screen. Sometimes they go try arm in arm to the medical complex, certain objects on the ground.

He gradual improvement is in its ability to interpret the flashes of light and they identify as lines and shapes, the doctor said.

Among other clients, the answer "varies but quite a bit."

"People who blindly probably have for a long time use so much,", Dagnelie said.

Time goes on, doctors hope that the device for people who suffer from macular degeneration, could extend the primary cause of vision loss in people over 60.

"We hope that 10-15 years something must we, that is quite useful, clinical,", the Dutch American doctor said.

Elias managed to do much work around the House. He recently the bathroom floor is equipped and visitors as he was still his table saw in the garage can hold several times to questions whether his 18-month old grandson, Anthony, was under the feet.

"He does everything." He said such a proud man, "his wife Dina."

Back in the living room of Konstantopoulos was sitting in his chair and drew the chubby-cheeked little boy who calls him "Papou."

"That was my biggest complaint." I never face have seen, "he said, weighs the young on the lap."

"I can see not his face." "Still."

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