A new visual illusion has shed light on a long-standing mystery
about how the brain works out the 3-D shapes of objects. 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 a 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. A team
of scientists from Giessen University, Yale and the Max Planck
Institute for Biological Cybernetics in Tübingen has recently
discovered how cells in visual cortex might help solve this
mystery. 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. "We
created the images by taking