The role of the ventromedial prefrontal cortex in memory consolidation

Abstract

"System-level memory consolidation theory" posits that the hippocampus an initially links the neocortical representations, followed by a shift to a hippocampus-independent neocortical network. With consolidation, an increase in activity in the human subgenual ventromedial prefrontal cortex (vmPFC) has repeatedly been shown. Previously we and others have proposed that this area might link the neocortical representational areas in remote memory, similarly as has been proposed for the rodent anterior cingulate cortex (ACC). Here, we review literature involving the human vmPFC to investigate if the results in other cognitive domains are in line with this proposal. We have taken into account reports on patients with lesions in this area, findings in reward and valuation, fear extinction, and confabulation studies, and integrated these with findings in consolidation studies. We conclude: Firstly, it is unlikely that the rodent ACC is homolog to the human subgenual vmPFC. It is more likely that the rodent infralimbic cortex is, as proposed in the fear extinction literature. Secondly, we propose that the function of the subgenual vmPFC is to integrate information which is represented in separate parts of the limbic system (the hippocampus, the amygdala, and the ventral striatum) and that the integrated representation in the subgenual vmPFC might subsequently be used to suppress irrelevant representations in the limbic system. With the progression of time, the importance of the integrated representation in the subgenual vmPFC increases, because it may replace some direct connectivity across the limbic areas which decays with time.