Ventromedial prefrontal cortex supports affective future simulation by integrating distributed knowledge

Abstract

Although the future often seems intangible, we can make it more concrete by imagining prospective events. Here, using functional MRI, we demonstrate a mechanism by which the ventromedial prefrontal cortex supports such episodic simulations, and thereby contributes to affective foresight: This region supports processes that (i) integrate knowledge related to the elements that constitute an episode and (ii) represent the episode's emergent affective quality. The ventromedial prefrontal cortex achieves such integration via interactions with distributed cortical regions that process the individual elements. Its activation then signals the affective quality of the ensuing episode, which goes beyond the combined affective quality of its constituting elements. The integrative process further augments long-term retention of the episode, making it available at later time points. This mechanism thus renders the future tangible, providing a basis for farsighted behavior.episodic future thinking | episodic memory | functional MRI | ventromedial prefrontal cortex | subjective value

Reducing future fears by suppressing the brain mechanisms underlying episodic simulation

“…Retrieval suppression is typically associated with modulation of hippocampal activity. We tested the further idea that suppressing recurring imaginings involves an additional modulation of vmPFC activation, consistent with this region's putative contribution to the facilitation of typical details of simulated scenarios (25,26). The findings strongly support these hypotheses.…”

“…The mPFC fosters the integration of overlapping memories into a common representation (56,57), presumably by representing past experiences during new learning (57) and by interacting with distributed brain regions that code for the shared elements (26). Over time, the mPFC thus binds typical features of similar episodes into a schematic model of the respective scenario (23,24,58).…”

“…Second, this context-dependent modulation should affect the effective connectivity of dlPFC with both the HC and the vmPFC (rather than with just the HC), given the proposed role of the vmPFC in recurrent simulations (23,24,26). Third, given the presumed inhibitory nature of the dlPFC signal, the top-down connectivity should be negative, so that activation in the dlPFC causes deactivation in the target regions.…”

“…Accumulating evidence suggests that this region comes to represent features that are shared across similar episodes, thus creating a schematic model of the respective scenario (23,24). Reactivation of such a model, in turn, can facilitate simulations by providing the details that are typical for the imagined situation (25,26). Accordingly, the vmPFC may especially contribute to simulations that share recurring features such as when someone persistently reimagines particular fears they have about their future.…”

“…Such "future suppression" may require the down-regulation of the HC, given its fundamental contribution to both the retrieval of past episodes and the mental construction of future events (20,21). Critically, however, unlike the suppression of recently acquired and unique memories, which has been the focus of most pertinent studies, the suppression of recurrent imaginings may also involve down-regulation of the vmPFC, given this region's putative involvement in facilitating access to typical, repeated event details that are part of a schematic model of the dreaded situation (23,24,26).…”