Variable binding by synaptic strength change

Abstract

Copyright and moral rights to this thesis/research project are retained by the author and/or other copyright owners. The work is supplied on the understanding that any use for commercial gain is strictly forbidden. A copy may be downloaded for personal, non-commercial, research or study without prior permission and without charge. Any use of the thesis/research project for private study or research must be properly acknowledged with reference to the work's full bibliographic details.This thesis/research project may not be reproduced in any format or medium, or extensive quotations taken from it, or its content changed in any way, without first obtaining permission in writing from the copyright holder(s).If you believe that any material held in the repository infringes copyright law, please contact the Repository Team at Middlesex University via the following email address:eprints@mdx.ac.ukThe item will be removed from the repository while any claim is being investigated. Journal …Connection ScienceArticle ID … CCOS395590 Variable binding is a difficult problem for neural networks. Two new mechanisms for binding by synaptic change are presented, and in both, bindings are erased and can be reused. The first is based on the commonly used learning mechanism of permanent change of synaptic weight, and the second on synaptic change which decays. Both are biologically motivated models. Simulations of binding on a paired association task are shown with the first mechanism succeeding with a 97.5% F-Score, and the second performing perfectly.Further simulations show that binding by decaying synaptic change copes with cross talk, and can be used for compositional semantics. It can be inferred that binding by permanent change accounts for these, but it faces the stability plasticity dilemma. Two other existing binding mechanisms, synchrony and active links, are compatible with these new mechanisms. All four mechanisms are compared and integrated in a Cell Assembly theory.

A neural cognitive architecture

“…The key problem is variable binding, and there are several solutions (e.g. (Shastri and Aijanagadde 1993;van der Velde and de Kamps 2006;Huyck 2009b)). It should be possible to directly translate a particular rule base automatically to neurons.…”

Conditions for cognitive self-organisation implied by visual-word processing

“…The role of neural binding in perception and cognition has long been recognised. Several authors have argued its theoretical necessity: von der Malsburg (1981), Dalenoort (1985), Smolensky (1990), Singer (1999), Treisman (1996), van der Velde and de Kamps (2006), and Huyck (2009), whereas various versions of the associated binding problem were analysed by Feldman (2013).…”

“…The state of temporary resonance may then be carried by neurons not involved in the actual task. Also, fast changes in the strength of synapses, distinct from the slowly developing synapses in Tanzi-Hebb learning, may play a role (Huyck, 2009).…”

“…An important issue in binding, consolidation, and learning is an adequate balance between robustness and plasticity, cf. (Huyck, 2009). To ensure stable, yet flexible binding, we will distinguish between outward and inward contexts.…”