OBJECTIVE: To investigate the effects of acute Panax quinquefolius (American ginseng) administration on steady state visually evoked potentials (SSVEPs) during completion of working memory and continuous performance tasks. METHODS: A randomised, double-blind, placebo controlled, balanced, cross-over trial was conducted in middle-aged volunteers aged between 40 and 60 years. Participants were administered 200 mg P. quinquefolius and placebo on two separate testing sessions. Six-h post-dose participants completed spatial working memory (SWM) and continuous performance (CP) tasks while SSVEP from a diffuse task-irrelevant 13 Hz flicker was recorded. RESULTS: During SWM retrieval, P. quinquefolius was associated with significantly reduced prefrontal SSVEP latency. There were no significant treatment effects on CP nor behavioural performance of either task. CONCLUSIONS: These findings provide preliminary evidence of increased recruitment of prefrontal brain regions during working memory processing following a single acute dose of P. quinquefolius
