Cross-Correlation Analysis of After Emotional Stimulation in EEG Using a Smartphone

Abstract

[Objective] The purpose of this study was to investigate the information processing process in the brain by cross-correlation analysis of brain waves after emotional stimulation with a smartphone. [Methods] The subjects were 23 healthy adults that were divided into two groups, namely stress and non-stress groups, via psychological examination. In the experiment, stimuli of relaxation, pleasant, unpleasant, pleasant sentence, and unpleasant sentence were displayed on a smartphone for the subject, and the brain waves were measured concurrently. To record the EEG data, the electrodes (19 channels) were placed according to the international 10/20 system. Coherence analysis was performed on the EEG, and the coherence values and time lag in 171 combinations among all channels in the alpha 1 band (8–10 Hz) were calculated. [Results] The time-lag between unpleasant, pleasant, and unpleasant sentences in the non-stress group was higher than that for the rest and pleasant stimuli. The stress group showed higher time-lag than the non-stress group at all stimulation times. [Discussion] The results imply that the stress group has slower information propagation compared to the non-stress group. Additionally, it can be suggested that text stimulation received from a smartphone has slow information propagation, regardless of its content.