Analyses of Stroop EEG using Event Related Potentials and Time-Frequency Decomposition

An event-related potential (ERP) measures the brain response that is the direct result of a specific sensory, cognitive, or motor event. In this paper we apply time-frequency analysis to the ERPs to investigate the sub-cognitive processes of the Stroop test. EEG data from 50 healthy participants are collected while performing the Stroop test. The test comprised of congruent and incongruent trials. Response time, response accuracy, and peak amplitudes and latencies are compared between congruent and incongruent trials. It is found that participants took significantly longer time to respond to incongruent trials than the congruent trials. It is also observed that the peak amplitudes in multiple ERPs are significantly higher in the congruent trials than incongruent trials. The time-frequency results revealed that brain oscillations in both congruent and incongruent trials increased in the higher beta range (18–30 Hz). We conclude that brain responses to stimulus are strongly correlated with higher beta band (18–30 Hz).