EVENT -RELATED POTENTIAL (ERP) SIGNALS ANALYSIS

The Event-Related Potential (ERP) components, PlOO and P300 are
thought to reflect visual and cognitive information processing, respectively.
Recent studies suggested that these ERPs are influenced by natural or
environmentally induced variables. The present study investigated the efficiency
of visual and cognitive information processing over time and also the effect of
caffeine intake on both visual and cognitive functions. The sample consisting of
ten healthy individuals (five female and five male), was submitted to a visual
discrimination task (oddball paradigm) at three different times (i.e., morning,
afternoon and evening) within the same day. Also, subjects were required to
undergo the same visual test after the administration of caffeine (65 mg). The
main components of interest; PIOO and P300 are studied and analyzed based on
two variables used to quantity the components: latency and amplitude. Results
suggest that visual and cognitive efficiency degrade over time (as observed by an
increase in latency and a decrease in amplitude in most subjects). After the
caffeine administration, the visual and cognitive efficiency for most subjects
seemed to improve (a decrease in latency while an increase in amplitude).
However, the caffeine effect was more prominent in a fatigue condition compared
to well-rest condition. Though partially confirmed the hypotheses, this study
provides evidences for the time-of-day and caffeine effects on both visual and
cognitive processing efficiency as proposed in the current literature.