The functional neuroanatomy of event-based and time-based prospective memory, and its improvement

Prospective memory anchors upcoming activities in future time and space either cued externally (event-based prospective memory) or internally (time-based prospective memory). It is key to remain autonomous and can be enhanced using incentives. To examine the neuronal underpinnings of prospective memory and any performance improvement, we randomly assigned 58 healthy older participants (60-75 years old, 36 women) to time-based and focal event-based prospective memory tasks using 7T-fMRI, with or without incentives. Event-based and time-based prospective memory differ in their functional neuroanatomy. The focal event-based task required activity important for the perception of relevant changes in the environment and for adapting the focus of attention to then respond swiftly. The time-based task, in contrast, involved regions supporting cognitive control or serving as a multimodal information buffer. Incentives had no effect in time-based prospective memory but recruited brain regions important for attention thus improving cue recognition in event-based prospective memory. This highlights the differences between these two prospective memory types and the need for differential approaches depending on the type of memory demand.