News and Tribune

Community News Network

March 4, 2013

Can eyes see outside of the head?

PITTSBURGH — Recently, we have witnessed remarkable, fictional-sounding advancements in science and medicine. There's a guy who can hear color, another with a bionic eye attached to his brain, and a woman fighting back against the debilitating symptoms of multiple sclerosis by placing electrodes on her tongue. But for our next trick, we're going to need a bucket of tadpoles with eyes on their butts and some good old-fashioned alternating current. In other words, things are about to get all kinds of weird.

There's a great deal of wow to unpack here, so let's take it piece by piece. Using embryos from the African clawed frog (Xenopus), scientists at Tufts' Center for Regenerative and Developmental Biology were able to transplant eye primordia — basically, the little nubs of flesh that will eventually grow into an eye — from one tadpole's head to another's posterior, flank or tail. They don't play around with nerve endings or "wiring" or anything like that. They just cut out the cells from the head, slice open a bit of the tail, and jam them in.

As the eyes grow, they send out snaking tendrils of nerve fiber, or axons. We know this because the "tissue donor" tadpoles — a term that makes it sound like they had a choice — were injected with tdTomato, a fluorescent red protein. This allowed the researchers to watch innervation, or nerve growth, as it happened. Of those eye primordia that sent out feelers, nearly half hardwired directly into the spine, while the other half built connections to the nearby stomach. None of the tadpoles grew tdTomato-marked pathways to the brain.

Before they could test the ectopic eyes however, the native ones had to be severed and removed. Otherwise, how would the scientists know which of the tadpole's three eyes was truly seeing? (Note: Severing optical nerves sounds like nasty business, but even these partially-developed tadpoles received anesthesia via fish sedative. Wounds healed completely within 24 hours.)

Text Only | Photo Reprints
Community News Network
LOCAL MAGAZINES
Easter 2014 photos


Click on any photo to purchase it.

SPECIAL CONTENT
Twitter Updates
Follow us on twitter
Hyperlocal Search
Premier Guide
Find a business

Walking Fingers
Maps, Menus, Store hours, Coupons, and more...
Premier Guide
AP Video
Crashed Air Algerie Plane Found in Mali Israel Mulls Ceasefire Amid Gaza Offensive In Case of Fire, Oxygen Masks for Pets Mobile App Gives Tour of Battle of Atlanta Sites Anti-violence Advocate Killed, but Not Silenced. Dempsey: Putin May Light Fire and Lose Control Arizona Prison Chief: Execution Wasn't Botched Calif. Police Investigate Peacock Shooting Death Raw: Protesters, Soldiers Clash in West Bank Police: Doctor Who Shot Gunman 'Saved Lives' 'Modern Family' Star on Gay Athletes Coming Out MN Twins Debut Beer Vending Machine DA: Pa. Doctor Fired Back at Hospital Gunman Raw: Iowa Police Dash Cam Shows Wild Chase Obama Seeks Limits on US Company Mergers Abroad Large Family to Share NJ Lottery Winnings U.S. Flights to Israel Resume After Ban Lifted Official: Air Algerie Flight 'probably Crashed' TSA Administrator on Politics and Flight Bans Raw: National Guard Helps Battle WA Wildfires
2013 Photos of the year


Take a look at our most memorable photos from 2013.