Temporal binding within and across events

• Serial recall transitions are reduced across context boundaries versus within events.
• Hippocampus and vlPFC show activation at boundaries related to later serial recall.
• Within-event serial recall is associated with enhanced hippocampal-vmPFC coupling.

Remembering the order in which events occur is a fundamental component of episodic memory. However, the neural mechanisms supporting serial recall remain unclear. Behaviorally, serial recall is greater for information encountered within the same event compared to across event boundaries, raising the possibility that contextual stability may modulate the cognitive and neural processes supporting serial encoding. In the present study, we used fMRI during the encoding of consecutive face and object stimuli to elucidate the neural encoding signatures supporting subsequent serial recall behavior both within and across events. We found that univariate BOLD activation in both the middle hippocampus and left ventrolateral prefrontal cortex (PFC) was associated with subsequent serial recall of items that occur across event boundaries. By contrast, successful serial encoding within events was associated with increased functional connectivity between the hippocampus and ventromedial PFC, but not with univariate activation in these or other regions. These findings build on evidence implicating hippocampal and PFC processes in encoding temporal aspects of memory. They further suggest that these encoding processes are influenced by whether binding occurs within a stable context or bridges two adjacent but distinct events.