Severed Gecko Tails Have A Mind Of Their Own
Even after they’re no longer connected to a lizard brain, gecko tails can flip, jump and lunge in response to their environment — and may even be able to evade predators.
Researchers have known for centuries that some animals can voluntarily shed parts of their bodies to keep from being eaten, but few studies have looked at the behavior of disposable body parts once they’ve fallen off.
Now, using high-speed video and a technique called electromyography, scientists have discovered that severed gecko tails exhibit complex behavior and even seem to react to environmental cues.
The scientists say that figuring out what controls the jumping gecko tail may help us understand why the paralyzed muscles of spinal cord injured patients sometimes exhibit spontaneous muscle contractions, which they hope could someday lead to treatments that restore some control over such movements.
After attaching electrodes to the tails of four adult leopard geckos, the researchers gently pinched the lizards to encourage them to shed their tails.
As soon as a gecko felt threatened, its tail began to twitch and eventually detached from the rest of its body in an amazing, but nearly bloodless, feat.
Rather than using up all their energy in a single short burst, the gecko tails seemed to modulate their muscle movement to conserve energy and maximize the unpredictability of their behavior.
The tails also changed direction and speed depending on what they bumped into, which suggests that the tails can independently sense and respond to their environment.
Although the researchers understand the benefits of a detachable tail with a mind of its own, they don’t yet know what’s controlling the tail’s complex movement.
According to Russell, figuring out what controls severed gecko tails might help us understand and treat some aspects of human spinal cord injury.
“With a spinal cord injury, what tends to happen is skeletal muscles tend to be paralyzed behind that event,” he said.
“For instance, if you injure your mid back, your lower limbs are put out of commission.”
Scientists know that networks of neurons called central pattern generators, or CPGs, can produce rhythmic movements that aren’t controlled by the brain, but they don’t know exactly how these neural networks function.
To study CPGs, scientists usually have to surgically damage an animal’s spinal cord in a procedure called a “spinal preparation“; geckos provide a unique model system because they naturally sever their own spinal cords.
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