Neural Representations of Reward-Related Memories Shift across Development

Rewards signal information in the environment that is valuable and thus useful to remember. Rewards benefit memory across development, but how reward-associated memories are represented in the brain has not been well characterized. Here we conducted pattern similarity analyses of fMRI data in male and female participants aged 8-25 to elucidate how neural representations in key memory-related brain areas are influenced by reward and how these relationships change across childhood and adolescence. We found that reward information was reflected in pattern similarity during encoding in the ventral temporal cortex and in changes in similarity from encoding to retrieval in anterior hippocampus (aHC). Strikingly, aHC reward-sensitive representations also varied with age such that adults' memory benefitted from stability of hippocampal representations, whereas younger participants' memory improvements were associated with greater drift in representations over time. Moreover, across all participants, reward-related univariate activation in the ventral tegmental area was associated with a greater tendency toward representational drift in aHC. Taken together, our findings demonstrate that reward modulates neural memory representations and that the representational patterns supporting reward-motivated memory shift with age.