A role for the hippocampal system in the learning of distal cortical associations

Clarification is required of the origins and capabilities of subsymbolic processing proceeding within local cortical areas and of the connections providing distal access between them. In tackling problems of distal association we focus on local neural areas engaging in integrated subsymbolic processing. Synchronization of responses of spatially separated local cortical areas with zero-phase lag provides the definition of association. Synchronous modulation of the excitability of local areas is adopted as a means of influencing the probability of them engaging in synchronous firing. The source of the modulation is a proposed mechanism for resolving the problems posed by cortical separation of local areas and the determination of their shared, specific contextual relevance. The mechanism involves the assumption that, in human cognition, local cortical areas can be substituted for sensory input from portions of the environment and via entorhinal cortex become represented as place fields in the hippocampus. This proposal conforms to the definition of `co-option´ in that preexisting structures which perform a particular function are presumed to be enlisted for a new use that is selectively advantageous in evolutionary terms. The proposed mechanism and its potential contribution to solution of the problem of identification of appropriate distal cortical associations are described