The effect of repetition priming on implicit recognition memory as measured by Fast Periodic Visual Stimulation and EEG

Introduction: The development of rapid and reliable neural measures of memory is an important goal of cognitive neuroscience research and clinical practice. Fast Periodic Visual Stimulation (FPVS) is a recently developed electroencephalography (EEG) method that involves presenting a mix of novel and previously-learnt stimuli at a fast rate. Recent work has shown that implicit recognition memory can be measured using FPVS, however the role of repetition priming remains unclear. Here, we attempted to separate out the effects of recognition memory and repetition priming by manipulating the degree of repetition of the stimuli to be remembered. Method: Twenty-two participants with a mean age of 20.8 (+/- 4.3) yrs. completed an FPVS-oddball paradigm with a varying number of repetitions of the oddball stimuli, ranging from very high repetition to no repetition. In addition to the EEG task, participants completed a behavioural recognition task and visual memory subtests from the Wechsler Memory Scale - 4th edition (WMS-IV). Results: An oddball memory response was observed in all four experimental conditions (very high repetition to no repetition) compared to the control condition (no oddball stimuli). The oddball memory response was largest in the very high repetition condition and smaller, but still significant, in conditions with less/no oddball repetition. Behavioural recognition performance was at ceiling, suggesting that all images were encoded successfully. There was no correlation with either behavioural memory performance or WMS-IV scores, suggesting the FPVS-oddball paradigm captures different memory processes than behavioural measures. Conclusion: Repetition priming significantly modulates the FPVS recognition memory response, however recognition is still detectable even in the total absence of repetition priming. The FPVS-oddball paradigm could potentially be developed into an objective and easy-to-administer memory assessment tool.