The impact of caffeine and taurine on the the P3 and N1 components of the event-related potential

Although marketed as the core ingredient in energy drinks, taurine's proposed status as a stimulant has only been tested in conjunction with caffeine, another energy drink constituent well-documented as facilitating attention and performance. The current study investigated the independent effect of taurine, and its interactive effect with caffeine, on information processing and resource allocation using the event-related potential (ERP) components P3 and N2. Participants (N=19) discriminated imminent driving accident scenes from standard traffic conditions under four different arousal conditions (placebo-placebo, caffeine-placebo, taurine-placebo, and caffeine-taurine). Caffeine and taurine dosages were equivalent to quantities within a standard 250 ml energy drink. The presence of taurine and/or caffeine did not significantly alter reaction time, N2 amplitude and latency, or P3 latency compared to placebo. Availability of attentional resources was enhanced after drug ingestion, as evidenced by significantly higher P3 amplitude at parietal midline and right hemisphere sites, compared to placebo. However, this effect was found solely in the presence of caffeine as opposed to the independent or interactive effect of taurine. The absence of a synergistic relationship between caffeine and taurine, or facilitative effect of taurine, suggests that the basic premises underlying energy drink consumption are questionable.