Dinesh's photos with the keyword: Stanislas Dehaene

www.groundsforsculpture.org The amazing efficiency of our reading process only serves to thicken the mystery surrounding its origins. How can our brain be so well adapted to a problem for which it could not possibly have evolved? How can the brain architecture of a strange bipedal primate turned hunter-gatherer have adjusted so perfectly, and in only a few thousand years, to to the challenges of visual word recognition? To clarify this problem, we will now turn to the cerebral circuits for reading. An amazing recent discovery shows that there is a specific cortical area for written words, much like the primary auditory area or the motor cortex that exist in all our brains. Even more surprisingly perhaps, this reading area seems to be identical in readers of English, Japanese, and Italian. Does this mean that there are universal brain mechanisms for reading?

The visual slippage induced by our own motion is just one of many cues that our brain edits out of our conscious belief. Many other features set our conscious world apart from the blurry signals that reach our senses. When we watch TV, for instance, the image flickers 50 to 60 times per second, and recordings show that this hidden rhythm enters our primary visual cortex, where neurons flicker at the same frequency. Fortunately we do not perceive those rhythmic flashes; the fine-grained temporal information that is present in our visual areas is filtered out before it reaches our awareness. Likewise, a very fine mesh of lines is encoded by our primary visual cortex, even though it cannot be seen. But our consciousness is not just nearly blind: it is an active observer that dramatically enhances and transforms the incoming image. On the retina and at the earliest stages of cortical processing, the center of our vision is massively expanded relative to the periphery: many more neurons care about the center of our gaze than about the surroundings. Yet we do not perceive the world as though giant magnifying lens; nor do we experience a sudden expansion of whichever face or word we decide to look at. Consciousness ceaselessly stabilizes our perception. ~ Page 144

A visual illusion called "Troxier fading" illustrates one of the many ways in which the subjective content of consciousness can be manipulated. Stare intently at the central cross. after a few seconds, some of the gray dots should vanish, then return at random moments. the objective stimulus is constant, but its subjective inetrpretation keeps changing. something must be changing inside your brain -- can we track it?