Human parietal retrieval states prioritize an absent temporal reference to reconstruct event order

Abstract

How the brain judges when something happened is thought to involve reconstruction--deriving temporal judgments from information recovered from memory rather than simply reading out a fixed temporal code. Testing this has been difficult because conventional tasks present both compared items at retrieval, so reinstatement could reflect cue processing as much as memory recovery. Here we dissociated what a judgment requires from what its cue supplies: during fMRI scanning, participants (n = 55) judged a targets temporal position relative to a milestone that was never shown at retrieval. We found that retrieval patterns in the precuneus and angular gyrus resembled the absent milestone more than the target, a bias strongest in the precuneus. Moreover, trial-by-trial similarity to the encoded path linking milestone to target--rather than to either alone--predicted correct judgments independently of retrieval activation. Human parietal retrieval is thus configured more by what a judgment requires than by what the cue supplies, providing content-specific representational evidence for reconstructive temporal-order memory.