Hippocampal involvement in glucose facilitation of recognition memory: Event-related potential components in a dual-task paradigm

Background - Glucose administration may facilitate hippocampus-mediated recognition memory (‘remember’ rather than familiarity ‘know’ responses). Objective - This study aimed to investigate the electrophysiological correlates of this phenomenon in a cohort of older individuals. Methods - In this double-blind placebo-controlled cross-over study, 12 older participants (mean age = 69.33 ± 1.69 years) completed the remember-know paradigm both with and without a concurrent tracking task while recording event-related potentials (ERPs). Results - Counter to predictions, glucose reduced overall accuracy. No treatment effects were found for proportion of Remember, Know and Guess responses, although there was a trend towards greater accuracy for ‘Remember’ responses following glucose. There was weak evidence for dissociation of drink effects on tracking with glucose being associated with preferential allocation of resources to ‘Remember’ over ‘Know’ responses. At P3 and F3 electrode sites, a significantly greater left parietal (LP) recollection effect and greater FN400 effect respectively were found for glucose. Conclusions - These findings do not support task effort modulation of the memory-enhancing effects of glucose. There was evidence of a greater glucose facilitatory effect for hippocampus-mediated LP recollection.