Our sense of sight is arguably our most important sense. Imagine how different your life would be if soon after birth, you lost the ability to see. For over 1.4 million children worldwide, that is their life. Being blind in developing countries like India has a costly impact: over 90% of blind children do not go to school, less than 50% make it to adulthood, and for those that do, only 20% are employed. But the real tragedy is that many of these cases of childhood blindness are completely avoidable and even treatable.
Snap! Crackle! Pop!
Those are the sounds that Professors David Hubel and Torsten Wiesel heard in the early 1950s when they recorded from neurons in the visual cortex of a cat, as they moved a bright line across its retina. During their recordings, they noticed a few interesting things: (1) the neurons fired only when the line was in a particular place on the retina, (2) the activity of these neurons changed depending on the orientation of the line, and (3) sometimes the neurons fired only when the line was moving in a particular direction.Continue reading
Envision this scenario. It’s the end of a grueling hike and you’re racing back to civilization along a trail in the mountains as darkness falls. You’ve become separated from your fellow hikers when all of a sudden the last beams of sunlight fade and the moonless night descends. You reach into your backpack for your flashlight only to realize that the batteries are dead. Accustomed to relying on your visual system, you panic upon being plunged into temporary blindness. But wait! All of a sudden the previously inaudible footsteps of your companions become heightened as you discriminate where they are and race off in the direction of their voices.Continue reading