Effects of caffeine on visual evoked potencial (P300) and neuromotor performance

Abstract

-The stimulant effects of caffeine on cognitive performance have been widely investigated. The visual evoked potential, specially the P300 component, has been used in studies that explain the stimulant mechanisms of caffeine through neurophysiological methods. In this context, the present study aimed to investigate electrophysiological changes (P300 latency) and modification of cognitive and motor performance produced by caffeine. Fifteen healthy volunteers, 9 women and 6 men (26 ± 5 years, 67 ± 12.5 kg) were submitted three times to the following procedure: electroencefalographic recording, Word Color Stroop Test, and visual discrimination task. Subjects took a gelatin caffeine capsule (400 mg) or a placebo (P1 and P2), in a randomized, crossover, double-blind design. A one-factor ANOVA and Tukey' post hoc test were used to compare dependent variables on the C, P1 and P2 moments. The statistical analyses indicated a non-significant decrease in reaction time, Stroop execution time and latency at Cz on the caffeine moment when compared to the others. Moreover, a non-significant increase in Stroop raw score and latency at Pz could be observed.The only significant result was found at Fz.These findings suggest that the positive tendency of caffeine to improve cognitive performance is probably associated with changes in the frontal cortex, a widely recognized attention area.KEY WORDS: P300, caffeine, neuromotor performance. Efeitos da ingestão de cafeína no potencial evocado visual (p300) e no desempenho neuromotorRESUMO -Os efeitos estimulantes da cafeína no desempenho cognitivo vêm sendo amplamente investigados. O potencial evocado visual (P300) tem sido empregado em estudos recentes que buscam elucidar os mecanismos excitatórios da cafeína através de métodos neurofisiológicos. Neste contexto, o presente estudo objetivou examinar as variações geradas pela cafeína em respostas eletrofisiológicas (latência do P300) e determinar modificações no desempenho cognitivo e motor. Para tanto, 15 indivíduos hígi-dos, sendo 9 mulheres e 6 homens (26 ± 5 anos, 67 ± 12,5 kg) foram submetidos por três vezes à seguinte rotina: aquisição de sinais eletroencefalográficos, Word Color Stroop Test e tarefa de discriminação visual. Foi administrada uma cápsula gelatinosa de 400 mg de cafeína ou de placebo (P1 e P2) em um desenho randomizado duplo-cego cruzado. Foi empregada a ANOVA com um fator e post hoc de Tukey -HSD para a comparação das variáveis nos momentos C, P1 e P2. O momento cafeína apresentou redução não significativa no tempo de reação, no tempo de execução do Stroop e na latência em Cz. Observou-se também aumento não significativo no escore bruto do Stroop e na latência em Pz. O único resultado significativo encontrado foi na latência em Fz.Assim, pode-se concluir que a tendência favorável à ingestão de cafeína na melhora das respostas cognitivas pode estar relacionada a mudanças em regiões específicas do cérebro, como o córtex frontal, área amplamente relacionada com os processos de atenção. PALAVRAS-CHAVE: P300, ...

Effects of caffeine on the electrophysiological, cognitive and motor responses of the central nervous system

“…Other studies that have analyzed the interaction between ERPs and caffeine are not conclusive. Some studies indicate a shortening of latency (17,18,(29)(30)(31), while others show an increase in amplitude (28,32). However, the use of different experimental conditions makes it impossible to compare the results.…”

“…Few ERP experiments have attempted to correlate the modulatory effects of caffeine on cognitive processes, attention and arousal in terms of P300 amplitude and latency (16,(29)(30)(31)(32). A combination of peripheral behavioral responses such as reaction time and attention together with central electrophysiological responses may contribute to the understanding of caffeine's mechanisms of action.…”

Effects of Caffeine on Electrophysiological and Neuropsychological Indices after Sleep Deprivation

“…However, other studies failed to demonstrate caffeine effects on cognitive functions, such as attention and memory [9][10][11] . This can be partially explained by the experimental design adopted, where subjects were physically and mentally rested.…”

Neuromodulatory effects of caffeine and bromazepam on visual event-related potential (P300): a comparative study

“…In a rec e n t s t u d y, a shorter P300 latency and higher amplitude, specifically at Fz, were observed after the administration of caffeine when compared to placebo. T h ese findings suggest that the tendency of caffeine to improve cognitive perf o rmance is pro b ably associated with changes in the frontal cortex, a widely recognized attention area 14 . Given some inconsistencies and contradictions in the current lite r a t ure, the effects of caffeine on ERPs have not been entirely clarified.…”