Mutual Information Analysis of the EEG before Photon Stimulation and during Photon Stimulation

The aim of the present study was to analysis nonlinear dependence of the electroencephalogram (EEG) during photon stimulation (during-PS) with cross mutual information (CMI). EEGs from during-PS and pre-PS were recorded in the 18 age-matched controls. Statistically significant differences were found for between during-PS and pre-PS using a nonparametric Wilcoxon (matched-pairs) signed-rank test in 16 channels. The results showed that the inter-hemispheric dependence was significantly higher during 5 Hz PS at temporal regions than before PS at delta and beta EEG bands. The intra-hemispheric dependence was significantly increased during 5 Hz PS at left intra-hemisphere parietal-occipital and right hemisphere temporal-parietal brain regions at the alpha EEG bands. In addition, the dependence was also significantly higher during-PS at theta band at the right intra-hemisphere frontal-parietal region in comparison to pre-PS. These results suggest a high functional connectivity during PS at the inter-hemisphere and intra-hemisphere and reveal functional topographic alterations not only present in the spontaneous EEG. This research may also increase the awareness of EEG PS response studies in clinical practice to uncover potential neurophysiologic abnormalities.