Individual alpha frequency modulates prediction error-driven memory encoding

Abstract

AbstractPrediction and memory are strongly intertwined, with predictions relying on memory retrieval, whilst also influencing memory encoding. However, it is unclear how prediction errors during learning, as measured by the N400 event-related potential (ERP), influence explicit memory performance, and how individual neural factors may modulate this relationship. The current study sought to investigate the effect of prediction and individual neural variability on memory processing, whilst exploring the N400 as a prediction error signal in a context extending beyond language. Participants (N= 48, females = 33) completed a study-test paradigm where they first viewed predictable and unpredictable four-item ‘ABCD’ sequences of outdoor scene images, whilst their brain activity was recorded using electroencephalography (EEG). Subsequently, their memory for the images was tested, and N400 patterns during learning were compared with memory outcomes. Strikingly, greater N400 amplitudes during learning were associated with enhanced memory at test for individuals with low versus high individual alpha frequencies (IAFs). This indicates that IAF may influence stimulus precision weightings and the extent to which prediction errors drive memory encoding. Memory was also strongest for predictable images in the ‘B’ position, suggesting that when processing longer sequences, the brain may prioritise the data deemed most informative for predictive model updating. Ultimately, the results provide novel insight into the effect of prediction on memory, by highlighting the role of inter-subject variability, whilst shedding light on the accumulation of predictions across sequences.