The retina actively seeks out new sights and ignores the commonplace, report Harvard University scientists. The researchers presented salamanders and rabbits with various visual scenes and studied the neural signals from retinal ganglion cells that deliver images to the brain. The sensitivity of the individual cells spiked when the animals were faced with things they hadn't seen before. From a press release about the work, published in this week's issue of the scientific journal Nature:
"Apparently our thirst for novelty begins in the eye itself," says Markus Meister, the Jeff C. Tarr Professor of Molecular and Cellular Biology in Harvard's Faculty of Arts and Sciences. "Our eyes report the visual world to the brain, but not very faithfully. Instead, the retina creates a cartoonist's sketch of the visual scene, highlighting key features while suppressing the less interesting regions."
These findings provide evidence that the ultimate goal of the visual system is not simply to construct internally an exact reproduction of the external world, Meister and his colleagues write in Nature. Rather, the system seeks to extract from the onslaught of raw visual information the few bits of data that are relevant to behavior. This entails the discarding of signals that are less useful, and dynamic retinal adaptation provides a means of stripping from the visual stream predictable and therefore less newsworthy signals.
