Event-Related Spectral Signatures of Prospective Memory

Prospective memory (PM) relies on the ability to form, maintain, and retrieve intentions during an ongoing activity. In this study we examined the neural oscillatory dynamics underlying distinct PM stages: intention formation (Cue trials), intention retention (Ongoing trials), and intention retrieval (PM Retrieval trials). These stages were investigated using two newly developed PM tasks: the Animal-cued Prospective Retrieval Task (Ac-PRT) and the Object-cued Prospective Retrieval Task (Oc-PRT).

In this cross-sectional observational study, twenty-three young adults (mean age = 20.50 years, standard deviation = 2.35) completed the tasks while electroencephalography (EEG) data were recorded.

Behavioral results showed that participants responded more slowly during the Ongoing trials compared with the Cue and PM Retrieval trials and were less accurate during PM Retrieval trials across both tasks. Event-related spectral perturbation (ERSP) analyses revealed differences in PM stages in both tasks. PM Retrieval trials had significantly greater alpha (8-12 Hz) and low beta (12-20 Hz) desynchronization within 350-650 ms relative to the Ongoing trials, potentially reflecting increased attentional control and task-set reconfiguration during intention retrieval. Cue trials showed enhanced alpha and low beta desynchronization relative to Ongoing trials, suggesting preparatory attentional engagement triggered by the cue. Task-specific effects included lower theta synchronization in addition to greater alpha and beta desynchronization in the Oc-PRT compared with the Ac-PRT, which may reflect differential engagement of cognitive control and semantic processing mechanisms.

The observed patterns in theta, alpha, and beta activity suggest that these oscillations are associated with task demands that vary across PM stages. Together, these findings identify neurophysiological signatures that may guide future research on age-related changes in prospective memory.