\u00e2\u20ac\u0153We created the images by taking random noise and smearing it out across the image in specific patterns. It\u00e2\u20ac\u2122s a bit like finger painting, except it’s done by computer\u00e2\u20ac\u009d, explains Roland Fleming, Professor of Psychology at the University of Giessen. \u00e2\u20ac\u0153The way the texture gets smeared out is not the way texture behaves in the real 3D world. But it allows us to selectively stimulate so-called \u00e2\u20ac\u02dccomplex cells\u00e2\u20ac\u2122 in visual cortex, which measure the local 2D orientation of patterns in the retinal image\u00e2\u20ac\u009d.<\/p>\n These cells \u00e2\u20ac\u201d whose discovery led to a Nobel Prize for David Hubel and Torsten Wiesel \u00e2\u20ac\u201c are often described as \u00e2\u20ac\u02dcedge detectors\u00e2\u20ac\u2122 because they respond to boundaries or edges in the image. What was not known was that these cells could play a key role in estimating 3D shape.<\/p>\n \u00e2\u20ac\u0153We asked people to adjust small probes to report what they saw. The settings allow us to reconstruct exactly which 3D shapes they perceived,\u00e2\u20ac\u009d says Heinrich B\u00c3\u00bclthoff, director of the department of Human Perception, Cognition and Action at the Max Planck Institute for Biological Cybernetics. \u00e2\u20ac\u0153What\u00e2\u20ac\u2122s striking is how close the results are to predictions of a model based on cell responses\u00e2\u20ac\u009d.<\/p>\n The authors suggest the strongest evidence implicating the cells comes from an experiment in which participants stared at patterns for 30 seconds at a time, to change the way the cells respond. The resulting \u00e2\u20ac\u02dcadaptation\u00e2\u20ac\u2122 causes random noise\u00e2\u20ac\u201dwhich normally looks completely flat\u00e2\u20ac\u201dto appear like a specific 3D shape<\/strong>.<\/p>\n \u00e2\u20ac\u0153It\u00e2\u20ac\u2122s a kind of aftereffect, a bit like when you stare at a waterfall for a while, adaptation makes things that are stationary look like they are moving in the opposite direction.\u00c2\u00a0 Except here, the aftereffect makes the noise look 3D<\/strong>,\u00e2\u20ac\u009d says Daniel Holtmann-Rice, who is currently doing his PhD at Yale University. \u00e2\u20ac\u0153We didn\u00e2\u20ac\u2122t think it was going to work.\u00c2\u00a0 It was so exciting to get the first data where we could clearly see the predicted shapes emerging in the participants\u00e2\u20ac\u2122 settings.\u00e2\u20ac\u009d<\/p>\n The authors are currently working on generalizing the findings to other kinds of information about 3D shape, such as shading and highlights.<\/p><\/blockquote>\n","protected":false},"excerpt":{"rendered":" From the Max Planck Institute press release: As dizzying as it may sound, the impression that we are living in a 3D world is actually a continuous fabrication of our… Read more »<\/a><\/p>\n","protected":false},"author":4,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[6],"tags":[42,18,363,12,41],"_links":{"self":[{"href":"https:\/\/therapytoronto.ca\/news\/wp-json\/wp\/v2\/posts\/300"}],"collection":[{"href":"https:\/\/therapytoronto.ca\/news\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/therapytoronto.ca\/news\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/therapytoronto.ca\/news\/wp-json\/wp\/v2\/users\/4"}],"replies":[{"embeddable":true,"href":"https:\/\/therapytoronto.ca\/news\/wp-json\/wp\/v2\/comments?post=300"}],"version-history":[{"count":2,"href":"https:\/\/therapytoronto.ca\/news\/wp-json\/wp\/v2\/posts\/300\/revisions"}],"predecessor-version":[{"id":302,"href":"https:\/\/therapytoronto.ca\/news\/wp-json\/wp\/v2\/posts\/300\/revisions\/302"}],"wp:attachment":[{"href":"https:\/\/therapytoronto.ca\/news\/wp-json\/wp\/v2\/media?parent=300"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/therapytoronto.ca\/news\/wp-json\/wp\/v2\/categories?post=300"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/therapytoronto.ca\/news\/wp-json\/wp\/v2\/tags?post=300"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}![\"\"](\"http:\/\/therapytoronto.ca\/images\/blogpics\/Brain2.jpg\" "\\"brain\\"")
As dizzying as it may sound, the impression that we are living in a 3D world is actually a continuous fabrication of our brains. When we look at things, the world gets projected onto the retina and information about the third dimension is lost\u00e2\u20ac\u201da bit like when a 3D object casts a shadow onto a flat, 2D wall. Somehow the brain is able to reconstruct the third dimension from the image, allowing us to experience a convincing 3D world.<\/strong> A team of scientists from Giessen University, Yale and the Max Planck Institute for Biological Cybernetics in T\u00c3\u00bcbingen has recently discovered how cells in visual cortex might help solve this mystery<\/strong>. They created special 2D patterns designed to stimulate specific nerve cells when we look at them. They find that the result is a vivid illusion of 3D shape, which suggests these cells play an important role in reconstructing 3D shape.<\/p>\n