Selectivity in post-encoding connectivity with high-level visual cortex is associated with reward-motivated memory.

Reward motivation has been demonstrated to enhance declarative memory by facilitating systems level consolidation. While high reward information is often intermixed with lower reward information during an experience, memory for those experiences prioritizes high value information. How is this selectivity achieved? One possibility is that post-encoding consolidation processes bias memory strengthening to those representations associated with higher reward. To test this hypothesis, we investigated the influence of differential reward motivation on the selectivity of post-encoding markers of systems-level memory consolidation. Human participants encoded intermixed, trial-unique memoranda that were associated with either high or low value during fMRI acquisition. Encoding was interleaved with periods of rest, allowing us to investigate experience-dependent changes in connectivity as they related to later memory. Behaviorally, we found that reward motivation enhanced 24-hour associative memory. Analysis of patterns of post-encoding connectivity showed that even though learning trials were intermixed, there was significantly greater connectivity with regions of high-level, category-selective visual cortex associated with high reward trials. Specifically, increased connectivity of category-selective visual cortex with both the ventral tegmental area and the anterior hippocampus predicted associative memory for high- but not low-reward memories. Critically, these results were independent of encoding-related connectivity and univariate activity measures. Thus, these findings support a model by which the selective stabilization of memories for salient events is supported by post-encoding interactions with sensory cortex associated with reward.

SIGNIFICANCE STATEMENT: Reward motivation is thought to promote memory by supporting memory consolidation. Yet, little is known as to how brain selects relevant information for subsequent consolidation based on reward. We show that experience-dependent changes in connectivity of both the anterior hippocampus and the ventral tegmental area with high-level visual cortex selectively predicts memory for high-reward memoranda at a 24-hour delay. These findings provide evidence for a novel mechanism guiding the consolidation of memories for valuable events, namely post-encoding interactions between neural systems supporting mesolimbic dopamine activation, episodic memory, and perception.