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Your Eye Sees Trouble Before You Do

• Creation Safaris
In slapstick comedy, the fall guy gets the pie in the face when the clown in front of him ducks. It’s funny because most of us instinctively duck when we see something coming. But two recent experimental studies are revealing new automated capabilities built into the eye and brain that are quicker and more automatic than our reflexes or the brain’s visual center. A team from the Canadian Institutes of Health, publishing in PNAS,1 ran experiments on a subject that had damage to the visual cortex. They were surprised to learn that the subject could still avoid obstacles in the way during hand-reach experiments. Another experiment showed that the obstacle avoidance was nullified when a 2-second delay was introduced, providing “compelling evidence that these mechanisms can operate in ‘real-time’ without direct input from primary visual cortex (V1),” they said. What does this mean? The subject “was able to code the position of the obstacles despite being unaware of their presence.” The researchers said scientists are in the dark about how this works. The visual inputs that are necessary for obstacle avoidance have remained unknown, and remain so now. “These findings have far-reaching implications, not only for our understanding of the time constraints under which different visual pathways operate, but also in relation to how these seemingly ‘primitive’ subcortical visual pathways can control complex everyday behavior without recourse to conscious vision.” The paper did not mention evolution. On the contrary, it ended, “the results of the current study clearly indicate that we have to rethink the role of what are often considered primitive visual pathways in the mediation of complex motor behavior.” It would seem evolutionists might call them primitive, but now we are learning they are surprisingly complex. An even more up-front mechanism was discovered by a Swiss team. New Scientist reported on a paper published in Nature Neuroscience that demonstrates the “eye sees trouble before the brain notices.” Certain neurons in the brain have been known to respond to sensations of approaching objects. Now, those neurons have been found in the retina itself. This means that eye cells can warn us of approaching danger without the brain’s help. It’s “an alarm system that’s as close to the front end of the organism as possible,” said Botond Roska (Friedrich Miescher Institute for Biomedical Research in Basel, Switzerland), because waiting for the brain to respond might take too long. The study was done with mice but is assumed to operate in all mammals. (For a related story, see Science Daily on news about the hippocampus, eye movements and memory.) Reporter Sanjida O'Connell of New Scientist speculated how this came about: “This ability may have evolved to speed escape from predators.”

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