Neural Map Formation Is A Side-Effect of Cooperative Mechanisms That Exist to Increase the Information Content Of Neural Representations

Tom Anastasio, Associate Professor, Molecular & Integrative Physiology, UIUC

In order to process sensory input, neural systems must first represent sensory information. Most sensory representations in the brain take the form of maps. Well know examples include retinotopic maps in the visual cortex, tonotopic maps in the auditory cortex, and the body-surface map (homunculus) in the primary somatosensory cortex. By simulating processes of competition and cooperation among real neurons, the self- organizing map (SOM) algorithm trains an array of output units so that units near each other in the array respond to similar inputs, thus forming a map. Most lower-order sensory neurons, of the type that provide input to sensory maps, have considerable background activity. We use the SOM to show that competitive mechanisms alone are inadequate to increase output information content in the presence of input background activity. Combining competition with cooperation dramatically increases input-output mutual information and, as a side-effect, forms a neural map.

Slides