Radiation ruling the nation
Scientists are attempting to clarify the path that leads to consciousness by following a single, bite-sized piece of information — the redness of an apple, for instance — as it moves into a person’s inner mind.
Recent research into the visual system suggests that a sight simply passing through the requisite vision channels in the brain isn’t enough for an experience to form. Studies that delicately divorce awareness from the related, but distinct, process of attention call into question the role of one of the key stops on the vision pipeline in creating conscious experience.
Other experiments that create the sensation of touch or hearing through sight alone hint at the way in which different kinds of inputs come together. So far, scientists haven’t followed enough individual paths to get a full picture. But they are hot on the trail, finding clues to how the brain builds conscious experience.
One of the best-understood systems in the brain is the complex network of nerve cells and structures that allow a person to see. Imprints on cells in the eye’s retina get shuttled to the thalamus, to the back of the brain and then up the ranks to increasingly specialized cells where color, motion, location and identity of objects are discerned.
After decades of research, today’s map of the vision system looks like a bowl of spaghetti thrown on the floor, with long, elegant lines connected by knotty tangles. But there’s an underlying method in this ocular madness: Information appears to flow in a prescribed direction.
After planting a vision in a person’s retina, scientists can then watch how one image moves through the brain. By asking viewers when they become aware of the vision, researchers may pinpoint where along the pipeline it pops into consciousness.
