The hippocampal formation - orbitomedial prefrontal cortex circuit in the attentional control of active memory

The long held view that the hippocampal formation is not only essential, bu t also solely responsible for declarative memory in humans (and by analogy non-human primates) has come into question. Based on extensive reciprocal c onnection patterns between the hippocampal formation and the orbitoventrome dial prefrontal cortex in primates and rats, a central role for the hippoca mpal formation in the attentional control of behavior is emerging. In this paper, evidence is reviewed showing that the hippocampal-orbitomedial prefr ontal cortex circuit may be involved in attentional monitoring of the inter nal sensorium. This attentional monitoring system, in a sense, is the worki ng memory of viscero-emotional processing. The hippocampal formation can th us be viewed as a discrepancy detector with respect to the relative activat ional status of cognitive/emotional set in the orbitomedial prefrontal cort ex. Discrepencies between the current representation of the internal milieu and the 'just-prior' representation held, 'on-line' in orbitomedial prefro ntal cortex associative working memory, are signaled from the hippocampus t o the prefrontal cortex prospective attentional systems to activate, proces s, and reconcile internal (past) with external (present) environments, and finally to effectively alter active working emotional 'sets' to exert cogni tive-emotional control of behavior. (C) 2001 Elsevier Science B.V. All righ ts reserved.