Nonnegative Predictive coding: New approaches to modeling cortical microcircuit function.

I present a modification of the Predictive Coding Model (PC, Rao & Ballard, 1999) to nonnegative mappings and representations. The new model retains the advantages of PC but claims to be biologically more plausible. Its major limitations yet is the iterative character of the bottom-up mapping (recognition) which is a consequence of the fact, that the bottom-up synaptic weight matrix and the top-down generative mapping are transposes of each other.

I finally present a new promising approach to learning an inverse of the generative mapping in the bottom-up path using biologically plausible mechanisms. In the new model in development top-down predictions are critically involved in neural self organization.