Aims: 

Caffeine is known as the most widely consumed stimulant of the central nervous system. Here, we investigated the acute effects of 3 mg/kg caffeine on human event related potentials (ERPs) in auditory and visual oddball paradigms.

Methods: 

We obtained ERPs from 11 university students in a double-blind, placebo-controlled target-detection paradigm. In the auditory task pitch was used as deviant feature. The standard tone (P=0.8) was 1 kHz, and the deviant tone (P=0.2) was 1.5 kHz. In the visual task a disc and a square were used as standard (P=0.8) and deviant (P=0.2), respectively. In both conditions, the SOA varied randomly between 1000–2000 ms. The effects of experimental conditions (Caffeine/Sham and Fz/Cz/Pz electrodes) were analysed with two-way ANOVAs on reaction times and amplitudes and latencies of both auditory and visual N100 and P300 components.

Results: 

Caffeine consumption shortened reaction time in both conditions, and decreased latencies of the deviant visual (but not the auditory) N100 and P300 components.

Conclusion: 

Caffeine caused positive effects on neural processing of target stimuli in the visual but not in the auditory task. Preliminary data suggests that caffeine may exert differential action in visual and auditory task conditions.