A dynamic neural field mechanism for self-organization

Abstract

As introduced by Amari, dynamic neural fields (DNF) are a mathematical formalism aiming to describe the spatio-temporal evolution of the electrical potential of a population of cortical neurons. Various cognitive tasks have been successfully solved using this paradigm, but nevertheless, tasks requiring learning and self-organizing abilities have rarely been addressed. Aiming to extend the applicative area of DNF, we are hereby interested in using this computational model to implement such self-organizing mechanisms. Adapting the Kohonen's classical algorithm for developing self-organizing maps (SOM), we propose a DNF-driven architecture that may deploy also a self-organizing mechanism. Benefiting from the biologically-inspired features of the DNF, the advantage of such structure is that the computation is fully-distributed among its entities. Unlike the classical SOM algorithm, that requires a centralized computation of the global maximum, our proposed architecture implements a distributed decision computation, based on the local competition mechanism deployed by neural fields. Once the architecture implemented, we investigate the capacity of different neural field equations to solve simple self-organization tasks. Our analysis concludes that the considered classical equations do not perform satisfactory. Highlighting the deficiencies of these equations that impeded them to behave as expected, we propose a new system of equations, enhancing the current models, in order to handle the observed undesired effects. In summary, the novelty of these equations consist in introducing an adaptive term that triggers the re-inhibition of a so-called “unsustainable” bump of the field's activity (one that no longer is stimulated by strong input, but only by strong lateral excitation). As a conclusion, a field driven by the new equations achieves good results in solving the considered self-organizing task. Our research opens thus the way to new approaches that aim using dynamic neural field to solve more complex cognitive tasks.