In a paper published this week in npj Regenerative Medicine, researchers led by Michael Levin, Ph.D., grafted eyes onto the trunks of tails of blind tadpoles. They then administered a neurotransmitter drug, already approved for use in humans, to encourage nerves to connect to the new eye. They tested the tadpoles’ potential new ability to distinguish color through a test in which they had to swim toward a red space rather than a blue one. While blind tadpoles passed the test only three percent of the time, tadpoles with grafted eyes that had also been treated with the neurotransmitter passed a whopping 29 percent of the time.

“The plasticity of the brain in recognizing that this new, weirdly placed patch of tissue on its back is providing visual data and is able to use that in the normal behavioral repertoire for learning and memory is just striking,” says Levin.

Demonstrating that blind tadpoles can now process visual information provides a potentially valuable roadmap for encouraging nerves to serve various parts of the body: a key milestone in regenerative medicine.

“The other amazing thing is that these animals were able to see with their eyes connected to the spinal cord, not the brain. This suggests that some of these kinds of implants… don’t necessarily require brain surgery for functional innervation.”

Press Coverage

• Fierce Biotech – Migraine drug activates transplanted eyes in tadpoles
• STAT – Transplanted eyes let tadpoles see through their tails
• New Scientist – Tadpoles learn to see with new eyes transplanted on their tails
• Live Science – Hind Sight: Blind Tadpoles See Via Eyes in Tails
• Research Gate – Blind tadpoles learn visually with eye grafted on tail