Clay Davenport
Cerebral Nomad
Pit vipers and boid snakes strike with paradoxical precision even when blindfolded, although their heat-sensing organs should not allow the formation of a sharp infrared image. A team at Technical University of Munich may have figured out this seemingly impossible feat.
Their skill has impressed scientists: "blindfolded snakes can strike a running rat behind the ears to avoid its sharp teeth," says physicist Leo van Hemmen of the Technical University of Munich. On each side of their face, these creatures have a pit organ that is basically a hole with a heat-sensitive membrane stretched across it.
It had been supposed that focusing worked as in a pinhole camera, except that the one-millimeter holes are too big. The answer may lie in image-processing algorithms. Van Hemmen's team have built a computational model that takes into account both the infrared noise created by moving prey and errors generated by the sensor membrane itself.
In their model, the signal reaching each receptor causes a neuron to fire, but the firing rate depends on the input received by all the other receptors. By tweaking how the receptors interact, the team could create precise images, even when there was a lot of background noise.
To minimize the errors caused by sensor noise the model required the membrane to be no more than 15 micrometers thick, which turns out to be exactly the thickness of the real membrane.
"We've found a simple way that something seemingly impossible could work in the snake," Van Hemmen says, replying to questions about whether the model describes what really happens. "If we could work it out, we're sure that nature could too."
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Their skill has impressed scientists: "blindfolded snakes can strike a running rat behind the ears to avoid its sharp teeth," says physicist Leo van Hemmen of the Technical University of Munich. On each side of their face, these creatures have a pit organ that is basically a hole with a heat-sensitive membrane stretched across it.
It had been supposed that focusing worked as in a pinhole camera, except that the one-millimeter holes are too big. The answer may lie in image-processing algorithms. Van Hemmen's team have built a computational model that takes into account both the infrared noise created by moving prey and errors generated by the sensor membrane itself.
In their model, the signal reaching each receptor causes a neuron to fire, but the firing rate depends on the input received by all the other receptors. By tweaking how the receptors interact, the team could create precise images, even when there was a lot of background noise.
To minimize the errors caused by sensor noise the model required the membrane to be no more than 15 micrometers thick, which turns out to be exactly the thickness of the real membrane.
"We've found a simple way that something seemingly impossible could work in the snake," Van Hemmen says, replying to questions about whether the model describes what really happens. "If we could work it out, we're sure that nature could too."
Link