Modern, high sensitivity, magnetic resonance (MR) imaging now allows non-invasive methods to resolve how the human brain responds to the three-dimensional structure of the visual world. A new paper in PNAS from an international collaborative team shows how these complex MR-signals can be resolved into basic elements of processing that are activated when human volunteers look at visual patterns that systematically change in perceived depth.
Hard problems are often solved by breaking them down into a set of smaller problems, each of which is individually easier to solve. This approach, sometimes called "divide and conquer", underlies the efficiency of many processes in modern business and manufacturing and is responsible for the surprising performance of modern artificial intelligence systems. Our own brains also use this strategy. Unsurprisingly, if a path to a solution is available, biological evolution and lifetime learning will discover it. Modern neuroscientific studies have contributed substantially to the identification of basic units that support the 'divide and conquer' approach.
For biological vision, the basic units of processing are called receptive fields, because they were initially defined by a limited surface area or field over which the neuron is receptive. Stimuli in the receptive field cause the neuron to respond with electrical impulses called action potentials, whereas stimuli outside this area cause no response. In the initial stages of visual processing in the cerebral cortex, the receptive fields are responsive not only to where the visual stimulus is positioned, but also its shape, orientation, movement, colour, texture and other properties.
Read the full story on the Department of Physiology, Anatomy and Genetics website.