Friday, November 25, 2005
Three Forms of Binding and their Neural Substrates: Alternatives to Temporal Synchrony
Three Forms of Binding and their Neural Substrates: Alternatives to Temporal Synchrony(PDF) by Randall C. O’Reilly, Richard S. Busby, and Rodolfo Soto, June 23, 2001
"Abstract
This paper presents three different ways of addressing the binding problem in different brain areas: generic neocortex,
hippocampus, and prefrontal cortex. None of these approaches involve the popular mechanism of temporal synchrony.
The first two involve conjunctive representations that bind by ensuring that different neural units are activated for
different combinations of input features. Specifically, we think the cortex constructs low-order conjunctions using
coarse-coded distributed representations to avoid the combinatorial explosion usually associated with conjunctive
solutions to the binding problem. We present a model that learns these representations in a challenging relational
binding task, and furthermore is capable of considerable generalization to novel inputs. Next, we review the idea that
the hippocampus performs conjunctive binding in long term memory through the use of higher-order conjunctions that
are much more specific to particular events than those in the cortex. Finally, we present a model of a very different form
of binding that involves the phonological loop — a mechanism for maintaining arbitrary sequences of phonemes in
active memory. This phonological system can be used to bind by continuously repeating the to-be-bound information
(e.g., “press left key for green X’s,...”). In total, this work suggests that instead of one simple and generic solution
to the binding problem, the brain has developed a number of specialized mechanisms that build on the strengths of
existing neural hardware in different brain areas."
"Abstract
This paper presents three different ways of addressing the binding problem in different brain areas: generic neocortex,
hippocampus, and prefrontal cortex. None of these approaches involve the popular mechanism of temporal synchrony.
The first two involve conjunctive representations that bind by ensuring that different neural units are activated for
different combinations of input features. Specifically, we think the cortex constructs low-order conjunctions using
coarse-coded distributed representations to avoid the combinatorial explosion usually associated with conjunctive
solutions to the binding problem. We present a model that learns these representations in a challenging relational
binding task, and furthermore is capable of considerable generalization to novel inputs. Next, we review the idea that
the hippocampus performs conjunctive binding in long term memory through the use of higher-order conjunctions that
are much more specific to particular events than those in the cortex. Finally, we present a model of a very different form
of binding that involves the phonological loop — a mechanism for maintaining arbitrary sequences of phonemes in
active memory. This phonological system can be used to bind by continuously repeating the to-be-bound information
(e.g., “press left key for green X’s,...”). In total, this work suggests that instead of one simple and generic solution
to the binding problem, the brain has developed a number of specialized mechanisms that build on the strengths of
existing neural hardware in different brain areas."
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