%0 Journal Article %A Raphael Kaplan %A Karl J Friston %T Hippocampal-entorhinal transformations in abstract frames of reference %D 2018 %R 10.1101/414524 %J bioRxiv %P 414524 %X Knowing how another’s preferences relate to our own is a central aspect of everyday decision-making, yet how the brain performs this transformation is unclear. Here, we ask whether the putative role of the hippocampal-entorhinal system in transforming first person and extra-personal spatial cues during navigation extends to transformations in abstract decision spaces. In our functional magnetic resonance imaging study, subjects learned a stranger’s preference for an everyday activity – relative to a personally known individual – and subsequently decided how the stranger’s preference relates to other familiar people’s preferences. Across reference frames, we observed signals in the retrosplenial cortex and hippocampal body during decisions that require precise memories for preferences. In contrast, the entorhinal cortex/subiculum exhibited reference frame-sensitive responses to the relative distance between the ratings of the stranger and the familiar choice options. Taken together, these data implicate the hippocampal-entorhinal system in the assimilation of knowledge in an abstract metric space. %U https://www.biorxiv.org/content/biorxiv/early/2018/09/11/414524.full.pdf